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Tiny House Plumbing: A Simple DIY Guide Including Tanks, Diagrams, And Costs

Tiny House Plumbing: A Simple DIY Guide Including Tanks, Diagrams, And Costs

tiny house plumbing
Plumbing in a tiny house can seem daunting at first — I know when I built my tiny house it seemed that way. But what I came to realize after learning a few tricks about how plumbing works in a tiny house is that it wasn’t as hard as it first seemed.

So in this guide, I wanted to lay out how to install pluming in your tiny house, how to connect things like a shower, sink, and toilet, and considerations around water tanks if you want to take your tiny house on the road. I’ll also dig into some of the costs to install plumbing into a tiny house as a DIYer and if you decide to hire a plumber.

How Does Tiny House Plumbing Work?

How Does Tiny House Plumbing Work

There are three main differences between a traditional house and a tiny house when it comes to plumbing: how the water comes into the house, dealing with a trailer, and the optional on-board water tank.

The great thing about tiny houses is that because your home is so small, you don’t need any long runs.If you design it right, the plumbing can be super easy to execute. Take time to plan ahead so that you don’t overcomplicate things.

Much like a traditional home, you’re going to have your water supply come into the house, then it usually forks, one line to the hot water heater, the other direct to your sink and shower. The line coming out of the hot water heater will then be your hot supply to your sink and shower.

I’ll give more details on this below.

Tiny House Plumbing Diagram

Tiny House Plumbing Diagram

If you’re anything like me, you need to see a general layout of how all the pipes and drains are laid out and connected in your tiny house plumbing system. Here is a diagram I put together of my tiny house’s plumbing system.

Tiny House Plumbing hot and cold water diagram


Hot and Cold Water Lines

hot and cold water lines in a tiny house

Drain Lines

drain lines in a tiny house

All my water supply lines were made out of PEX, which I color coded. I purchased a roll of red PEX line for hot water and my cold water line was blue colored PEX. This helped me keep things straight in my head. All my drain lines were 2”PVC pipes.

As you can see, the water enters my house near the tongue of my tiny house trailer. The line splits here, with the cold line going directly into my house from the bottom and the other line going up to my tankless hot water heater, which is mounted on the outside.

The cold water line entered into my house behind my kitchen cabinets where it T’ed [???] off. The water line to the left went to the cold water line for the shower. The line to the right followed the wall, turned the corner and came up to feed it’s way to my sink.

The hot water followed a similar path right next to the cold water line using red PEX line.

Drain lines come down in two places: one under my shower, the other from my kitchen sink. Both of these drop through the floor, through my trailer and hang just below the bottom of my trailer. They are connected into one drain line so I have one central point where the water comes out the side. It can then be connected to a septic or RV sewer line connection.

PEX Plumbing Makes Tiny House Plumbing Easy

PEX Plumbing Makes Tiny House Plumbing Easy

For many years we used copper and PVC lines for plumbing which were complicated to connect and would split at the slightest sign of freezing. Today, modern plumbing has brought in the use of PEX, and for us tiny house folks, this is a god send.

PEX is the name for Cross-Linked Polyethylene water lines. This stuff is awesome: pretty inexpensive, super easy to work with, can withstand freezing temperatures, and is perfect for the DIYer. It’s risen in popularity over the past few decades and is now the staple of any new plumbing system.

pex 90 degree fittingThe great part about PEX is that it’s super easy to connect with quick-connect fittings. These fittings allow you to cut your PEX tubing, clean up the ends, push it into the fitting, and lock it into place with a water-tight connection. Gone are the days of sweating a copper pipe to add flux, and you can forget about gluing up PVC.

Quick connectors or “push fittings” are often referred to as “Shark Bites” (a brand name of a popular quick connector) and they are amazing. You literally just take the pipe and push it in and small metal teeth grip the pipe to create a water tight seal.

What’s even better is that if you make a mistake, you just use a little magnet to quickly disconnect the fitting with ease. Most quick connectors will also allow you to connect PEX lines to other types of lines: copper, PVC, etc.

The PEX line itself comes in several sizes, colors and lengths. Typically, new homes are plumbed with ¾” PEX, but my house was ½” line. PEX tubing can be bought just about anywhere. At the time of writing this post, I can buy two rolls of 50-foot PEX (one blue and one red) for around $50 online or about $60 at your local big box hardware store. That will be more than enough to do your tiny house.

why you should consider a tankless hot water heaterAs mentioned before, you can purchase colored lines to help you color code your water lines as you route them through your house — usually blue for the cold supply lines and red for the hot supply lines. There is no difference between the colors, people just use them to make it easy to identify different lines.

The last thing you should know about PEX is that, unlike other water line options, you can actually bend it around corners. There are limits to this of course, as you don’t want to kink the PEX line. For ¾” PEX line, you’re not supposed to bend it more than 7” in diameter. That doesn’t usually mean much to people, which is why they actually sell PEX bend supports to make sure you get it right.

pex tubing bendcorrect bend radius for pex tubing
Tubing Size Minimum Bend Radius Minimum Bend Diameter
3/8″ 4″ 8″
1/2″ 85″ 10″
5/8″ 6″ 12″
3/4″ 7″ 14″
1″ 9″ 18″

Minimum recommended bending radius is 8 times the outside diameter of PEX (8 x OD). For 1/2″ PEX with OD of 5/8″, minimum bending radius is 8 x 5/8″ = 5″. Over-bending the PEX pipe, deforms its’ round shape, restricts flow and over-stresses the pipe. Note: minimum bending diameter only refers to the 90-degree and 180-degree (U shaped) bends. Parallel runs of pipe can be spaced as close as necessary.

As a side note, if you do kink the PEX line, it’s often recommended to discard it and use a new section.

Tiny House Water Hookups

Tiny House Water Hookups

There are two main ways to hook up water to your tiny house. One is for more longer term, the other is for short term connections if you want to stay mobile. Either method will face one main challenge: freezing as it goes from the water source to your tiny house. Whatever method you use, make sure to insulate it well.

RV Water Inlet

RV Water Inlet on a tiny house

The first method is using a spigot as your water source. Make sure you use a drink safe hose, as a regular hose will leech a lot of nasty chemicals into your drinking water. From the hose, you’re going to want to use an RV water inlet to allow the water to enter your tiny house.

RV Water Inlet fitting

Off the back of this inlet, you can tie in your PEX tubing and run it wherever you need to go.

PROS

  • Simple to hook up
  • Works at most campgrounds
  • Quick to connect and disconnect
  • Good or mobile tiny houses

CONS

  • More prone to freezing
  • Slightly more expensive
  • Leaky hose connections common
  • Can snag hose and damage inlet

Direct Connection

Direct Connection for pex fitting

This is a more permanent method for tiny houses that aren’t as mobile or not mobile at all. I initially started with the above method on my house, but found the hose froze pretty often, even in my moderate climate. Recently, I switched over to having a buried PEX line that came right below my hitch, then brought it up to my house. I added insulation to the PEX line, insulating the small span between the ground and the house.

I also should note that I actually extended my insulation a foot beneath the ground for good measure.

PROS

  • Less prone to freezing
  • Loks neater on outside
  • Cheapest method
  • Lasts long term

CONS

  • Not meant to be moved
  • Needs to be cut if you do move
  • Requires you to bury water line
  • More technical skill required

Tiny House Water Tanks

Tiny House Water Tanks

Many people want to be able to live in their tiny house while traveling around or live off the grid in their tiny house. A water tank is a great way to make your tiny house more livable when you don’t have a direct connection.

The average American uses around 100 gallons of water per day, so if you’re going to use a water tank as your primary water source, you’re going to have to adjust your relationship with water in a big way. After living in my tiny house for years, I’ve averaged out to around 11 gallons per day.

Water Tanks in a tiny houseYou’ll need water to cook with, take a shower, wash your dishes, drink and general cleaning tasks. It can add up quickly when you remember that water is 8 lbs. a gallon. I like the option of having a tank, but realistically, you’re going to need a reliable water source from a well or city connection.

The biggest tank I’ve seen in a tiny house was around 80 gallons, which accounts for 640 extra pounds of weight on your trailer. What is more, you can’t just have your tank on one side of your trailer or your weight will be distributed unevenly side to side.

You also want your tank to be located directly over your axels, if at all possible. This is because too much weight on the tongue or in the rear (lifting up at the tongue) can be very dangerous. Properly balancing the load on your trailer is critical, and that can be difficult when a water tank is involved. Water tanks can also slosh, throwing around the weight. Your load and calculations need to take into account that your water tank will get lighter as you use water, too.

You have two options to pump water from a storage tank to your sink.

12 Volt Sink Pump From Water Tank

12 Volt Sink Pump From Water Tank

This is the more advanced option, where you’ll have a 12-volt pump that draws water out from your tiny house water tank and up to your sink faucet. This option usually is only good for cold water, because you’d have to draw so much water through your lines and hot water heater that you’d waste a lot of water waiting for hot water to come through.

12 Volt Sink Pump From Water Tank diagram


Simple Foot Pump Sink From Water Tank

Simple Foot Pump Sink From Water Tank

For those who don’t want to get into complicated 12-volt pumps, a foot pump can be a really great option. This is a dead simple system that only requires a few connections and a few parts.
Simple Foot Pump Sink From Water Tank diagram


How Much Does It Cost To Put Plumbing In A Tiny House?

How Much Does It Cost To Put Plumbing In A Tiny House

Plumbing your tiny house doesn’t cost a whole lot unless you hire a plumber. Luckily, PEX makes this very approachable and your drain lines, which will be PVC, are going to be very short runs. If you’re able to avoid hiring a plumber, then you can save big. If you do end up hiring a plumber, expect to pay anywhere between $100-$200 an hour for their work, plus materials.

Here is an example of plumbing costs from my tiny house build:


  • 25-foot roll of RED PEX: $13.78
  • 25-foot roll of BLUE PEX: $13.78
  • Five right-angle elbow push fittings: $51.40
  • One Tee-style push fitting: $13.45
  • Name brand shower faucet: $89.95
  • Name brand kitchen faucet: $105.95
  • 20 feet schedule 40 PVC drain line: $11.56
  • PVC assorted fittings: $3.48
  • Sink P trap: $8.37
  • Shower P trap: $4.38
  • PVC pipe cement: $8.98
  • PEX pipe cutter: $9.71
  • PEX deburring tool: $11.56
  • Sharkbite removal tool: $1.98
  • One bag nail clamp (50 pieces): $12.04

Total Cost To Plumb My Tiny House: $351.39

Other Tiny House Plumbing Costs

Other Tiny House Plumbing Costs

I also wanted to share a few things that you might want to factor into your own plans and budget that aren’t included in the above list.

The biggest one, of course, is any labor costs if you hire a plumber. A plumber will cost anywhere from $100-$200 an hour. You can expect about five to ten hours of work for your entire house including your hot water heater, sinks, showers, drain lines, etc.

Not included in my list most notably is any toilets, as I opted for a composting toilet. Going the route of a traditional toilet will add a good bit of work and cost on your part. Not because they are overly difficult or expensive, but because you’ll have to get the city involved to have a flush toilet.

The “tap fee” to tie into the city sewer line and the water line is very expensive. My city charges a whopping $11,582 just to connect to the lines at the street. After that, you’re still responsible for connecting that line from the street to your house, which will run you about $10 per foot for the water line and $15 per foot for the sewer line. Alternatively, you may be able to install a septic system, starting around $5,000.

how to install a septic system

Another cost I didn’t include here was a water heater. I use a Rinnai v53e tankless hot water heater, which after 5 years, I still love. Having endless hot water when I need it means I can take long hot showers without worry or running out of hot water and not having to account for a lot of extra weight in water storage.

Since I only heat water as I use it, I use propane for this, which is a great option for me because I live off the grid. While I don’t love relying on a fossil fuel (propane), it’s the most practical way for me to heat water off the grid.

tankless hot water heater

The last thing you might want to consider is if you are going to have a bathroom sink, tub, dishwasher or laundry machine. These will all add material costs and labor, so just be sure to account for them in your budget, plans and in calculations for weight!

Tiny House Plumbing Tips

Tiny House Plumbing Tips

From someone who did a lot of things wrong and a few things right, here are some of my best tiny house plumbing tips for when you build your own tiny house.
The biggest tip I’d give is to have your shower and kitchen sink be as close to each other as possible. If you have the shower on one side of an interior wall and the sink on the other side of that same wall, you’ll save a lot of extra work.

Plan Your System

An hour of planning ahead will save you a ton of time down the road, not to mention a lot of headaches.

Consider Venting

Venting your plumbing system is a big deal, without it your drain lines won’t drain properly. I used an in-line “air admittance vale” which allows air to enter the water line without a full drain going through the roof. These vales are contentious because they can fail, but it worked for my purposes.

Plan Your Drains Carefully

I didn’t do this and, when I went to installe my shower drain line, I discovered a metal beam from my trailer right below where the drain needed to be.

Plan Exhaust Venting

Make sure you have the proper space to vent your exhaust vents for your hot water heater, stove and shower fans. I had a lot of trouble with these because the vent tubes were so big. That lead me to getting an exterior mounted hot water heater, which is designed to be outside and vent directly from the unit to the outside.

Slope Drain Lines Properly

Drain lines need to be sloped in a very specific way — ¼ of an inch per foot. Too shallow of a slope and you’ll have clogs, but too steep and your solids will not drain. Getting this right is very important.

Not Leveling Your Tiny House

If your tiny house isn’t perfectly level, all your drain lines will not be slopped right, leading to clogs. You want to make sure your sinks drain properly and that water won’t pool in them. A properly installed drain line will not work if the whole house is off kilter.

Think About Freezing Lines

You want to take frost prevention seriously. Wherever possible, keep your water lines on the inside of your heated envelope, running the lines within interior walls vs. exterior walls. For the connection from your water source to your tiny house, insulate and use heater tape when possible.

Have A Whole House Shut Off

The best addition to my system was a $5 ball valve to help me turn off my water to the house when I go out of town, need to service my plumbing system, or if a leak were to ever happen.

Always Have Access

Make sure you always have a way to access the water lines in your tiny house. It doesn’t have to be the most convenient access, but if you can always get at your water lines, you can fix any problems that arise.

Carefully Cut And Deburr PEX

Push fittings are great, but you need to make sure your cuts are perfectly straight so that when you push the tubing into the fitting, it seals well. Also use a deburr tool to make sure the cut is perfectly clean.

Don’t Reuse Fittings Or Tubing

If you have to disassemble a fitting for some reason, best practice is to replace the tubing and fitting all together. Many manufacturers will say their fitting can be reused a few times and some folks don’t mind reusing the fittings, but in my mind, buying a new fitting for $5 is good peace of mind.

If you kink your PEX tubing, you should cut a new piece and replace it. Here again, for a few cents a foot, the cost of knowing you won’t have an issue is well worth it.

Tankless Hot Water Heaters Are Your Friend

If you’ve never heard of or had one, tankless hot water heaters are amazing. I ended up with a Rinnai hot water heater and I love it! Tankless hot water heaters essentially take cold water and run it over a heated coil exchanger to heat the water as it passes through the unit. This is great because you’re not heating water when you’re not using it, which is great for being off the grid. You won’t ever run out of hot water, and since it isn’t a tank, you don’t have the bulk or weight of a tank.

Remember That Water Is Very Heavy

Since we are building on a trailer, we need to make sure we take into account the water that’s in our water lines, in our hot water heaters (if we have a tank hot water heater) and in a tiny house water tank.

Water is very heavy, weighing in at around 8 lbs. per gallon. If we have a water tank in our tiny house that holds 50 gallons of water, that’s over 400 lbs! And if our hot water heater has a tank of 40 gallons, that’s 320 lbs. So if you have either of these, you need to work it into your weight calculations for your trailer.

Consider RV Parts

RV’s have a few features around connecting to utilities when at a campground which are very helpful to tiny house folks. Fresh water inlets, access doors, sprayers, RV plugs, etc., all are useful when connecting tiny houses to the grid.

Your Turn!

  • What are you planning for in your tiny house plumbing?
  • What tiny house water hookup will you use?
  • Are you going to have a tiny house water tank?

Tiny House Dimensions: What Size Can A Tiny House Be Without Breaking The Law?

Tiny House Dimensions: What Size Can A Tiny House Be Without Breaking The Law?

tiny house dimensionsOne of the first questions I asked when building my own tiny house was how big should a tiny house be? There are several ways to answer this question, but it really comes down to whether you’re going to build your tiny house on a trailer or on the ground.

Most people want a tiny house they can tow down the road to travel or move if the need arises. So the focus here will be on tiny houses built on a trailer.

The Height Of A Tiny House: 13.5 Feet Tall

The Height Of A Tiny House

How high a tiny house can be is really governed by the height limitations of the Department of Transportation (DOT). More specifically, you want a tiny house that can fit under bridges and overheads while you drive down the road.

Most bridges on your major highways and on many side roads are built to have a clearance of at least 13.5 feet. That means you’ll want to consider building your tiny house just shy of that to be on the safe side.

My friend drove his tiny under a bridge where the sign stated it was 13.5 feet tall, but since it’s construction, had been repaved. My friend ended up pealing his ridge cap off his tiny house because of it.

The Width Of A Tiny House: 8.5 Feet Wide

The Width Of A Tiny House

The width of a tiny house is also dictated by the DOT if you’re on a trailer. In most states, you need your trailer to be less than 8.5 feet wide or you’ll need a special wide load permit. Understand that this measurement goes from the two widest points, which is usually your wheel wells. You should measure from the outside of the fender or tire to the opposite side of the fender or tire.

My suggestion is that you build your tiny house to be as wide as you can, but account for any roof overhang that might stick out. Build around the wheel well so that you have just enough insulation around it to maximize internal dimensions.

The Length Of A Tiny House: Up To 30 Feet Long

The Length Of A Tiny House

Here’s the really important thing to understand about tiny house dimensions. Because our height and width are constrained by the maximum size set by the DOT, if we want to increase our square footage, it means we have to extend the length of the trailer because we can’t build in any other direction.

Another element to this is your tow vehicle. In most cases, your maximum length will be 53 feet minus the length of your truck. Trucks suited to tow a large tiny house are typically 20-23 feet long, so your tiny house can be up to 30 feet long.

I should also note that the DOT primarily uses weight as its primary determining factor of upper limits. If your truck and tiny house on a trailer is over a gross vehicle weight (GVW) of 26,000 lbs, you’ll require special permits and a CDL driver.

Tiny House Square Footage

Tiny House Square Footage

Tiny Houses can range from 60 square feet up to 400 square feet when built on a trailer. Of course, you can build bigger if you build on a foundation. Typically your tiny house can be up to 8 feet wide inside, so your length will be the main variable that impacts square footage.

You’ll notice that a lot of tiny houses tend to be around 200 square feet — that’s because most people don’t want to have to tow a really big trailer. A 24-foot or 26-foot trailer is very cumbersome to tow, and since most people are pretty nervous about that size, going bigger isn’t very practical.

Also consider that the higher the square footage of a house, the larger the tow vehicle needs to be.

Here is a chart of the various trailer dimensions and their corresponding square footage sizes:

Trailer Length Trailer Width Square Footage
8 8 64 sq/ft
12 8 96 sq/ft
20 8 160 sq/ft
22 8 176 sq/ft
24 8 192 sq/ft
26 8 208 sq/ft
28 8 224 sq/ft
30 8 240 sq/ft
34* 8 272 sq/ft
36* 8 288 sq/ft
43* 8 344 sq/ft

*Gooseneck trailers only

When Do I Need a CDL To Tow My Tiny House?

When Do I Need a CDL To Tow My Tiny House

A Commercial Drivers Licenses (CDL) is required based on a few rules such as size or weight. While this is set by the federal government, it’s left up to individual states to set their own standards and oversee licensing.

Type of License Description Vehicles You May Drive
Class A CDL Required to operate any combination of vehicles with a gross combination weight rating (GVWR) of 26,001 or more pounds, provided the towed vehicle is heavier than 10,000 pounds. Tractor-trailers (also known as Semi, Big Rig or 18-wheeler), Truck and trailer combos, Tanker vehicles, Livestock carriers, Flatbeds. Most Class B and Class C vehicles, depending on endorsement requirements
Class B CDL Required to operate operate any single vehicle that isn’t hitched to a trailer (commercial trucks that have an attached cab and cargo area with a combined weight greater than 26,000 pounds, as well as trucks with a detached towed cargo vehicle that weighs less than 10,000 pounds). Straight trucks, Large buses (city buses, tourist buses, and school buses), Segmented buses, Box trucks (including delivery trucks and furniture trucks), Dump trucks with small trailers. Some Class C vehicles with the correct endorsements.
Class C CDL Required to operate a single vehicle with GVWR of less than 26,001 pounds or a vehicle towing another vehicle that weighs less than 10,000 pounds, or transports 16 or more passengers, including the driver. Double/Triple Trailers, Buses, Tank Trucks, HazMat Vehicles

Tiny House Trailer Dimensions

Tiny House Trailer Dimensions

An important part of this equation is understanding that the trailer you build your tiny house on is another limiting factor. If you can only build up to 13.5 feet tall, you actually have to subtract the height of the trailer to determine the interior useable space. Also account for wall and roof thickness in your calculations.

What this means is that for every inch of trailer height, you’ll have an inch less of space inside. The biggest determination of trailer height is your trailer style, of which there are three main types. Keep in mind the numbers below are averages and you’ll see some variations between manufacturers.

Utility Trailer Dimensions For A Tiny House

Utility Trailer Dimensions For A Tiny House

The most common trailer style to use is a utility style trailer. These are sometimes referred to as “bumper pull” or a “drop axle trailer.”

tiny house utility trailer

A typical utility trailer is around 13 inches from ground to bottom of trailer, 18 inches from ground to top of trailer deck, and 25 inches from ground to top of the wheel well.

tiny house utility trailer dimensions

Your common utility trailer will be exactly 8.5 feet wide from the outside of the wheel to the outside of the opposite wheel. Your wheels with wheel wells will typically be 15 inches wide, giving you an inside dimension of 72 inches between the wheel wells of your tiny house trailer.

tiny house utitlity trailer width dimensions

Popular Utility Trailer Sizes

Trailer Size Description
8 feet x 20 feet One of the most popular sizes because of its ease in transporting for tiny house dwellers who intend to spend a lot of time on the road.
8 feet x 24 feet This popular size allows more livable space while staying close enough to 20’ to still be comfortable to tow.
8 feet x 30 feet For those who have a family or prefer more room inside your tiny home, this length allows for more livable space while still being relatively easy to pull. Typically preferred for folks planning to live full-time in their homes.

Gooseneck Trailer Dimensions For A Tiny House

goosneck trailer dimensions

A gooseneck trailer uses a fifth wheel attachment point to tow with and is characterized by the hitch going up, over, then down again for towing. People like these because they’re a bit easier to tow and make tighter turns.

gooseneck trailer for tiny house

The other advantage to these is that you can build over the arm of the gooseneck, allowing you to have a longer tiny house. Normally you’d have to subtract the length of your tow vehicle from the maximum of 53 feet. Since the gooseneck actually goes over the truck bed, you regain some of that space.

The downside to goosenecks is their trailer decks are often thicker (but can hold more weight). Your typical gooseneck trailer will measure 17 inches from ground to bottom of trailer, 32 inches from ground to top of the trailer deck, and most often the wheel wells are flush with the deck height, so the top of the wheel well will also be 32 inches from the ground.

tiny house gooseneck trailer dimensions

Your common gooseneck will be exactly 8.5 feet wide from the outside of the wheel to the outside of the opposite wheel. Your wheels with wheel wells will typically be 15 inches wide, but built into or even under the trailer deck, giving you a full width of 8.5 feet since there are no wheels to block your building on it.

tiny house gooseneck trailer width dimensions

How Much Living Space Can You Have In A Gooseneck Trailer Tiny House?

Length of Bed: Trailer Size Length of Goose neck Total Length of Trailer Total Livable length
12′ 8 20′ 19′
14′ 8 22′ 21′
16′ 8 24′ 23′
18′ 8 26′ 25′
20′ 8 28′ 27′
22′ 8 30′ 29′
24′ 8 32′ 31′
26′ 8 34′ 33′
28′ 8 36′ 35′
30′ 8 38′ 37′
32′ 8 40′ 39′
34′ 8 42′ 41′
36′ 8 44′ 43′

Popular Gooseneck Trailer Sizes

Trailer Size Description
8.5 feet x 26 feet The most popular size, a 26-foot gooseneck allows for 33 feet of livable space since the extra length will ride above the vehicle pulling your home.
8.5 feet x 36 feet This is the maximum length for a gooseneck trailer. With the additional living space sitting above the hitch, a tiny house of this size will actually have 43 feet of livable space and 44 feet in total length.

Deck Over Trailer Dimensions For A Tiny House

Deck Over Trailer Dimensions For A Tiny House

While it is an option, a deck over trailer isn’t too popular because of how much vertical height you sacrifice, eating into your inside dimensions for living space. However, some people like this style of trailer because it makes for a simpler building process where you don’t have to worry about building around wheel wells.

tiny house deck over trailer

As mentioned, the downside to deck over trailers are that their trailer decks are much taller to go over the wheel well. Your typical deck over trailer will measure 24 inches from ground to bottom of trailer. It will measure 30 inches from ground to top of the trailer deck. Finally the wheel wells are under the deck, the wheel well right under the bottom of the trailer member, so the top of the wheel well will be 24 inches from ground.

tiny house deck over trailer dimensions

Your deck over trailer will be exactly 8.5 feet wide from the outside of the wheel to the outside of the opposite wheel. Your wheels with wheel wells will typically be 15 inches wide, but built in under the trailer deck, giving you a full width of 8.5 feet since there are no wheels to block your building on it.

deck over trailer width dimensions

Popular Deck Over Trailer Sizes

Trailer Size Description
8.5 feet x 20 feet One of the most popular sizes because of its ease in transporting for tiny house dwellers who intend to spend a lot of time on the road.
8.5 feet x 24 feet This popular size allows more livable space while staying close enough to 20’ to still be comfortable to tow.
8.5 feet x 30 feet For those who have a family or prefer more room inside your tiny home, this length allows for more livable space while still being relatively easy to pull. Typically preferred for folks planning to live full-time in their homes.

10-Foot-Wide Trailer Dimensions For A Tiny House

10-Foot-Wide Trailer Dimensions For A Tiny House

These trailers don’t differ too much from the above style trailer other than measuring 10 feet wide or more. If you decide go with a tiny house that is 10 feet wide, you’ll need to have a special oversized permit to transport it. You might also be required to have a CLD driver with flag escort vehicles depending on the state.

A typical trailer built to be 10 feet wide will be done in the style of a utility trailer. You’ll find that these trailers are typically around 13 inches from ground to bottom of trailer, 18 inches from ground to top of trailer deck, and 25 inches from ground to top of the wheel well.

10-Foot-Wide Trailer For A Tiny House

Your common utility trailer will be exactly 10 feet wide from the outside of the wheel to the outside of the opposite wheel. Your wheels with wheel wells will typically be 15 inches wide, giving you an inside dimension of 90 inches between the wheel wells of your tiny house trailer.

Tiny House 10-Foot-Wide Trailer Dimensions

Popular 10-Foot-Wide Trailer Sizes

Trailer Size Description
10 feet x 26 feet One of the most popular sizes because of its ease in transporting for tiny house dwellers who intend to spend a lot of time on the road.
10 feet x 30 feet For those who have a family or prefer more room inside your tiny home, this length allows for more livable space while still being relatively easy to pull. Typically preferred for folks planning to live full-time in their homes.

Tiny House Interior Dimensions

Tiny House Interior Dimensions

As mentioned, the biggest determination of your interior space will be from the deck height of your trailer, then of course your trailer length. Since you can only build up to 13.5 feet tall, you’ll have to subtract your trailer deck height and then also account for wall and roof thickness.

Tiny House Interior Width: 80 inches wide

Tiny House Interior Width

Because most wheel wells are a pretty standard size, you’ll have 72 inches between the wheel wells themselves. If you choose to build your walls above them, you can achieve a maximum of 80 inches wide from the inside of one wall, to the inside of the wall on the other side.

Tiny House Interior Length: Up To 29 feet long

Tiny House Interior Length

The length of your trailer will determine this dimension. A good rule of thumb is to take your trailer deck length and subtract 8 inches (4 inch thick walls times two).

Tiny House Interior Height: 10.5 feet tall

Tiny House Interior Height

Your inside height will be a function of your trailer deck height, minus your roof thickness, minus your subfloor, minus your flooring.

You can have a tiny house up to 13.5 feet tall. Often trailers are around 24 inches from ground to top of the deck, your sub floor is usually 4 inches thick, your flooring is up to an inch thick, and then your roof will be anywhere from 4-6 inches thick from inside finishes to the top ridge cap of your roofing.

I’d suggest also subtracting 2-4 inches as a safety margin.

Tiny House Loft Interior Dimensions: Up To 4 Feet 2 inches tall

Tiny House Loft Interior Dimensions

Don’t forget to check how your design will impact your tiny house loft height. Your main floor in your tiny house can be just barely taller that you are, giving you clearance for your head as you walk under your loft, but if your roof is too thick or you give yourself too much head room under the loft, you’re going to have a very small loft.

Let’s say, after accounting for roof thickness, trailer height, floor thickness, etc., you have 10.5 feet of inside vertical space. If you are 6 feet tall, your loft inside height will be about 50 inches tall. This is because you need to account for the loft floor supporting beams and decking.

tiny house loft

HOW TO SET UP A

TINY HOUSE

LOFT


Typically, your loft is built on 4x4s with a ½-inch piece of plywood on top. On top of that, you’re going to put your mattress, which can be anywhere from 4-12 inches thick. So crunch your numbers to make sure your loft height is going to work for you.

The final thing to consider is your roof style. If you have a standard hip roof, the peak will be directly in the middle of your bed, which is great if you’re a solo person and can sit up right in the middle. The sides of the hip roof will slope down on either side based on your roof slope, typically a 12:12 or 6:12 pitch.

You could also choose to have a shed style roof running from side to side or front to back. You could put the high end of your shed roof over the loft to maximize your headroom there.

Tiny House Dimensions For Canada

Tiny House Dimensions For Canada

In Canada, the size constraints are pretty much identical to those in the United States. While there are some variations between the provinces of Canada, because there is so much trucking between the two countries, they have pretty much matched each other.

Tiny House Dimensions For Australia In Meters / Metres

Tiny House Dimensions For Australia In Meters

I used to live in Alice Springs, so I’ve always been interested in tiny houses in Australia, particularly because housing costs are so insane there.

Centre-axled trailers (legally known as pig trailers) must not exceed 12.5 metres overall. The maximum distance from tow hitch to centre-line of the axle(s) must not exceed 8.5 metres. The rear overhang must not exceed the lesser of 3.7 metres, or the length of the load carrying area (or body) ahead of the rear overhang line.

Legal maximum towing weights in Australia, for tow vehicles under 4.5 tonne, the maximum laden trailer weight is the lesser of that allowed by the tow vehicle, tow hitch, or the maximum trailer mass. This overrides earlier legislation limiting towed weight to 1.5 times the tow vehicle’s unladen weight.

Determine The Right Size Tiny House For You

Determine The Right Size Tiny House For You

As you can see, there are a lot of variables that come into play determining the size of a tiny house, most of which stems from the trailer you choose. The main variable you can control to size your tiny house is modifying the length. A longer house will give you more square footage.

Your Turn!

  • What size trailer are you going to build on?

Tiny House Stairs: How To Build Them And Clever Design Ideas With Photos

Tiny House Stairs: How To Build Them And Clever Design Ideas With Photos

Tiny House Stairs and How To Build ThemMany people don’t like the idea of climbing a ladder in their tiny house, so building in a set of tiny house stairs is an option that has become more and more popular over the years. Some are even looking to save space by using stairs with storage to make it easier to get up to their tiny house loft.

When I started my build, the idea of stairs in my tiny house never crossed my mind, but with the built-in storage under a set of stairs, this is a really smart option. Like many things, if I had to do it all over again, I might too have built some tiny house stairs with storage.

Why You Should Consider Tiny House Stairs

Why You Should Consider Tiny House Stairs

Take it from me, a guy who has lived in his tiny house for almost 8 years now, climbing a ladder each night and coming down each morning can wear on you. When my ladder is set up to get into my loft, I can’t move between the living room and the kitchen, which means I have to set it up and take it down each time I want to use it. The point is, a set of stairs in my tiny house would be really nice!

When people first started building tiny houses, the houses were much smaller. At the time, the largest tiny home I saw was 150 square feet, built on an 18-foot trailer. These days people are going bigger, usually building off of a 24-foot trailer, or even all the way up to 30+ foot trailers.

If you’re going to build a tiny house on a 20-foot trailer or smaller, you’re most likely going to need to use a ladder because tiny house stairs take up a lot of room. For most people, a set of stairs is a great idea when you have more room in the larger trailer sizes. You’ll need enough run in your stairs to get up to your loft and just enough width to still have a usable living space next to it.

Tiny House Stairs Vs A Loft Ladder

Tiny House Stairs Vs A Loft Ladder

Choosing to go with stairs over a ladder is a big design decision and one that’s not easily fixed in a tiny house. While there are some really great benefits to having stairs, there are also some draw backs. Here are some pros and cons spelled out.

TINY HOUSE STAIRS

PROS

  • Easy to get up into your loft
  • Lots of storage below stairs
  • Allows for bed to be lofted, saving space
  • Adds a visual element to the house
  • No ladder to get in the way

CONS

  • Additional costs in lumber and hardware
  • More complex of a build
  • Takes up a sizeable chunk of space
  • Can’t use space above stairs
  • More complex building process

TINY HOUSE LADDER

PROS

  • Takes up the least amount of space
  • Pretty simple construction
  • Lowest cost method
  • Can be used on multiple lofts
  • Can be stowed away

CONS

  • Harder to get up in the loft
  • Blocks ground floor
  • No built-in storage
  • More risk of falling
  • Requires woodworking skill

 

How To Build Tiny House Stairs For Your Loft

How To Build Tiny House Stairs For Your Loft

The easiest way to approach building stairs for your tiny house is to think of it as a series of boxes that are stacked together to form your stairs. I find this approach to be the simplest for DIYers because trying to figure out all the rise and run calculations of traditional stairs is complicated.

The other benefit of this approach is that using a series of boxes allows you to have the structure ideal for maximizing storage space. Traditional stairs have stringers that block you from fully using the space under the stairs, but using my stacked box method, you can use all the available space. It’s also easy to install shelves or drawers and apply cabinet doors to the front of these, because essentially what you’re creating is a beefed up version of a cabinet carcass.

Finally, this method is great because you have some flexibility in the future, as you could potentially unscrew the boxes from each other and rearrange them to better suit your needs. Now let’s talk about how to actually build these.

Calculate The Dimensions Of A Tiny House Staircase

Calculate The Dimensions Of A Tiny House Staircase

There are a few critical dimensions to your staircase: width, rise and run. The width of the stairs is the dimension across the stair tread. The rise is how much your stairs will gain vertically over the run of the stairs. The total stair run is the longest dimension of the stairs, from the first step to the top of your loft.

Since you’re going to use the box method, I’d suggest taking the total stair run and divide it by how big your steps are going to be. You’ll have to play with the numbers here because you want something large enough to fit your foot comfortably as you walk up and is practical for your storage needs. I’d suggest starting with boxes 12 inches wide on the outside.

Calculating Number Of Steps

Calculating Number Of Steps

The easiest way is to take the total stair run and divide it by how wide you want your boxes to be. Keep in mind you want your stairs big enough to fit your foot and the steps up to be manageable. Ideally each step will be the same height so you don’t trip on varying heights of steps.

Example:

TINY HOUSE STAIRS MEASUREMENT EXAMPLE

MEASUREMENTS

  • Total stair run: 10 feet (120 inches)
  • Total stair height: 7 feet (84 inches)
  • Typical stair step height: 7”

FORMULA

84 inches / 7 inches = 12 steps @ 7” tall

120 inches / 12 steps = 10 inches per stair step run

Layout Your Tiny House Stairs Storage

Layout Your Tiny House Stairs Storage

Because we’re going to use a collection of wooden boxes to actually build the stairs, let’s first start with roughing out the general composition of these boxes, then play with the location.

You might want to make a comprehensive list of what is going to go into your stair storage. Things like your wardrobe, cleaning supplies, pantry, book cases, a place to file important documents, office supplies, etc. Start with your tallest item and your largest item, as you’re going to want to make sure you accommodate these first. You can get a good idea of how I approached this when I designed my tiny house closet.

Once you know what you need to store, mock up the storage boxes with simple graph paper, maybe even cut them out so you can play with different configurations. Think about how often you’re going to use the items, putting things you use everyday in the most easily accessible spots, while lesser used items should be stored down low or up above eye level.

The tops of your boxes are also going to make up the actual steps, so ensure that the dimensions are going to be the proper width for your stair step run and rise. The other boxes that make up the lower parts of the stairs, those not part of the actual step, can be any size, but ideally still standardized boxes so they all fit together.

What I suggest is to come up with a few standard form factors so your steps are modular and can be moved around into different configurations and still fit together into a form factor that gives you the right overall dimensions. Realize that the top steps can only be as wide as a step, but your lower boxes could be double or triple width because they don’t make up the steps, they just support them.

deign your tiny house stair modules

creating tiny house stair modules

Building Your Boxes

Building Boxes for tiny house stairs

Because these boxes are going to be load bearing, we want to make sure they’re very strong. If you’re not skilled at woodworking, simple boxes will do the job. I’d use at least ½-inch thick plywood with a decently smooth finish, even if you’re going to paint it. For my cabinets, I chose a Baltic Birch Plywood that was about $50 a sheet.

The easiest joint to use on your boxes is a standard butt joint — just lay one end onto the other. Use high-quality screws to fasten, but also glue each joint with wood glue. Wood glue will actually hold stronger than the screws will, so don’t skip gluing each joint.

Determine the dimension of the sides of your boxes and cut your lumber to its finished dimensions, and keep in mind your butt joints. You’ll want to account for the material that will be laid on its edge and subtract that material thickness.

Assemble your sides into the box frame, gluing and screwing as you go. Make sure you check that the box is squared up and then attach the bottom (or back) of the box. You’ll want the bottom edge of the sides to rest on the bottom’s wood. Pre-drill your holes, screw and glue.

Tools For Building Boxes


STEP 1

Measure height, length and depth (width of stair treads) where the staircase will fit. The rise and tread width will vary depending on how tall the entire staircase is. Determine size, shape and the placement of individual boxes and how they fit into the overall staircase layout.

measuring size of staircase

STEP 2

Measure and cut the top, bottom and sides of each box.

Construction Tip: Sides should support top board.

right and wrong way to build boxes

step box construction

STEP 3

Glue and screw top, bottom and sides together using simple butt joint. Be sure to double-check that all corners are perfectly square and flush.

glue and screw boxes together

STEP 4

After the glue has dried, cut and attached back to each box with screws.

attach back to boxes

STEP 5

Assemble individual boxes into staircase configuration. Tie boxes together with 1-1/2″ wood screws.  Then, attach entire staircase assembly to wall with longer 3″ screws. Make sure to hit the wall studs so that entire stairs are securely anchored in place.

assemble boxes into stairs and screw together

A nice touch to make your boxes feel a lot nicer and look polished is to use a 1/8-inch round over bit in a hand router. This will round out the edges with the smallest radius so the edge is more comfortable to the touch and helps give it a more finished look. Round over bits should come with a bearing on the end so it can easily be run over the edge for a nice consistent trim.

Clever Stair Storage Ideas

Clever Stair Storage Ideas

Here is are some pretty clever ways to build your stairs with lots of storage for your tiny house.

curved stairs in a tiny houseKeep it simple with curved stairs, a large wardrobe and a few baskets
box storage under stair treadsMake your stairs into drawers! Use this often-wasted space for storage
built in storage for stairsPull-out storage built into tiny house stairs
pantry under stairsPull-out pantry to grab food while you cook
use steep steps to save floor spaceUse steep steps to save space up to your loft
keep space big inside underneath stairsKeep inside space big and open for lots of storage
use color on stair drawersAdd a pop of color with your cabinet faces. Notice the shoe storage?
use minimalistic design for tiny house stairsKeep it minimalistic with a basic plywood for those on a budget
removable stair treadsHave removeable treads for deep storage options
hatch on stair landingTake advantage of awkward spaces with a stair landing hatch
narrow part of stairs for shoe storageUse the narrow part of the stairs for extra shoe storage
pull out shelves on tiny house stairsMake it easy to get at things in the very back with pull out shelves
alternating stair treadsGot a narrow space? Use alternating tread stairs to save space
alternating stiar treads to loftFor smaller tiny houses, use alternating tread to get up to the loft
modified ladder doubles as storage spaceA modified ladder with a shallower angle doubles as storage space
using a loft ladder instead of stairs to save spaceConsider just using a loft ladder instead of stairs to save more space
incorporate a bench seat into your stepsIncorporate a bench seat into your steps as multi-function furniture
using found items to build a stair caseStack found items that add up to a staircase and double as storage
Build in a desk along with your storage for an under-stair officeBuild in a desk along with your storage for an under-stair office
Build in a filing cabinet, stool and desktop under your stairsBuild in a filing cabinet, stool and desktop under your stairs
open shelf storage under your tiny house stairsOpt for open shelf storage under your tiny house stairs
Add kitchen storage under tiny house stairsAdd kitchen storage for cooking and more
Use a mix of drawers, doors and other elements in stair designUse a mix of drawers, doors and other elements
Put kitchen underneath stairs to save roomPut your kitchen underneath your stairs to save more room

Your Turn!

  • What makes you want a tiny house staircase over a ladder?
  • What tiny house stair storage are you drawn to?

Contracts Are Your Friend When Having A Tiny House Built

Contracts Are Your Friend When Having A Tiny House Built

More and more people are turning to builders of tiny homes to build their house.  When I first started the tiny house movement everyone was building their own tiny house, but that isn’t the case today.  Over the years I’ve found several really great builders, but I’ve also found a lot of really terrible builders.  My only advice is that buyer beware is the best advice I can give.

I felt the need to write this post today because there is clearly a need for people to understand how to protect yourself during this process.  I’ve seen countless examples of people not using common sense when it comes to hiring a builder and so here I am making this P.S.A.

When You Hire A Builder, Have This:

  1. Signed contract
  2. Build and payment timeline
  3. Detailed set of plans
  4. Process for changes
  5. Plan for when things go wrong
  6. Vetted references

 

Before I get into what each of these things are, I feel the need to justify the need for these things, not because they require justification, but because people seem to think they’re not needed.  It honestly blows my mind when I hear a horror story of a builder and I always ask, “do you have a contract?” 95% of the time the answer is “no”.

A Tiny House Contract With A Builder Does The Following:

  • Gets people on the same page
  • Reduces disagreements
  • Highlights future problems before they happen
  • Can help ward off bad builders
  • Gives you a leg to stand on in court if need be

If you’re entering into any agreement in life that’s more than $1,000 you should have something signed. The bigger the price tag, the more time you need to spend on the contract.  When I am considering whether to put together a document, I ask myself this: “Am I willing to lose or walk away from this money?”  If the answer is no, I draw up a contract.

I need to put a bit of tough love on all of you here, because most people I’ve run into think contracts aren’t necessary.  You need a contract and several other documents when hiring a professional to build your house.  If you don’t, I have a really hard time feeling sorry for you when it all goes bad.  Being a responsible adult means taking common sense steps like drawing up a contract on things like this.

So let’s get into what is involved with each of these things.

how much does a tiny house cost

You Need A Contract When You Hire A Builder Or Contractor:

Before you give over one dollar, you need to have a contract signed.  Why?  Because a contract is simply a tool to make sure everyone is on the same page.  People shy away from contracts because they sound complicated, they could be expensive, they are so formal or too “corporate.”

This is the exact opposite of how you should feel.  I love contracts, seriously!  I know it’s a little weird, but I really do.

The way I like to think about contracts is, they’re a tool that lets me understand the other person.  That’s it!  In life I’ve found that most disagreements happen when I do something when the other person expected something else.  If we can both agree on what we expect, most disagreements won’t happen.

So we use a contract to carefully outline what we want, what we expect, how we are going to go about it, and what the plan is. What I’ve found is we outline these things, sit down with the person and we suddenly find out we were thinking different things.  That’s great because we can align our thinking and fix it now.

A contract is best to be drawn up by a lawyer, but really any good builder should have a template handy.  You can get free templates online and customize to your needs.  Be wary of anyone who seems hesitant to work with you on a contract.  Bad and dishonest builders shy away from contracts. Quality builders love contracts because a contract lets them understand their customer and prevent disagreements.

You Should Have A Detailed Building Timeline:

contract timelines

In addition to the contract, you need a timeline.  A timeline outlines who does what and when.  You should outline when each phase of the build is to be completed.  Break down the build into milestones: Design finalized, construction starts, walls erected, roof completed, siding/windows/doors, interior finishes, etc.  For each of these things have a due date and tie those due dates to payments.

Along with a build schedule I would recommend insisting on a formal update every 2 weeks. Write this into the contract, along with what defines an “update”.  It can be a simple email with photos, but honestly I’d do it in person or do a virtual check in where they Skype or Face Time you and walk around the in progress house.  You want to see your house – actually lay eyes on it, don’t take their word for it!

For updates I’d stipulate in the contract:

  • Summary of work completed since last update (100 words or so)
  • 5 photos included with each updated, showing work that was completed
  • Summary of any delays and actions to fix it
  • Summary of work to be done by next update
  • Any items that need to be discussed or addressed

An important note here is you need to compare the work done to the timeline you’ve setup. Compare the last set of updates “work to be done” with the subsequent updates list of “work completed.” The update list should match. If it doesn’t, the builder should have a plan to catch up and explanation.  You should build in some time for setbacks. Be reasonable because delays happen, but set expectations for how much of a delay is too much.

Have A Detailed Set Of Plans As Part Of The Contract:

house plansA set of professionally generated plans are an investment to achieve a successful build.  Plans are an effective way to communicate exactly what you want.

Plans will typically cost $1,000 or more, but it’s something that you shouldn’t skimp on.  You want the plans to include specific dimensions, electrical, plumbing, and other utilities.  The other very important aspect to plans is the materials list.  You literally need to spec out every material in the house along with any mechanical or appliances.

Why so much detail in the material list?  Because it will help the builder price correctly and remove any questions when it comes to what needs to go into the house.   Really shady builders will often swap materials for cheaper versions and pocket the difference.

Have A Process For Changes:

changes will happen in buildingThis is typically a good signal of a quality builder, they rely heavily on rigid processes and insist on “change orders”.  In your contract you need to specifically state that any changes not signed off BEFOREHAND are not allowed and you aren’t responsible for paying for them.

A change order is simple document that states that you were planing on doing one thing, but for whatever reason something needs to be changed.  It should outline what the change is very specifically and needs to include the change of charges.  Even if there are no additional charges, it needs to specifically state that the cost is $0.00 in the document.

 

Things to require change orders are:

  • Changes to materials, parts or appliances
  • Agreements on delays
  • Changes in build, layout, design, colors or other elements
  • Any additions
  • Any changes to final billable costs or credits
  • Anything that wasn’t planned for

Plan For When Things Go Wrong:

Building a tiny house is a complex and things will go wrong.  It most likely won’t be a big deal, but it will happen.  Both sides need to be reasonable and considerate, but you also need to know when to draw the line.  The best piece of advice I can give here is that things are best resolved through productive conversations and understanding.

Be clear about what is bothering you, calmly state what you thought was going to happen, what did happen and propose possible solutions.  When you talk about issues, make sure you stop talking and listen when they’re speaking and ask for the same respect.  Do your best to keep your emotions in check.

Before you even start building, while you’re putting together your contract, sit down with the builder and say “I want to figure out a good way for us to resolve issues if they ever come up and want to work together on solutions together.”  If you have a specific conversation about this it can prevent a lot of heartache later on.

Often contracts will have a mediation process, where a third party hears both sides and determines what the fair thing to do is.  I’d suggest having the following:

  • Define a process that can help the situation early on
  • Define a mediation process
  • Define the location or jurisdiction for any legal proceedings if it needs to go to court
  • Define who pays for what in mediation and legal fees

Vet every builder with multiple references

First off, if a builder has never built a tiny house, run away as fast as you can.  Even if they were a builder of normal homes, that’s not good enough.  Why would you take the chance?

Any builder you engage you need to talk to multiple references.  In those interviews I’d strongly suggest you going to meet them in person and ask ahead of time to see the house they had built.  Most homeowners are proud of their house and love to show it off.  It will give you a chance to see the quality of the builder’s work and give you a chance to see real world examples which can be useful in your own build.

If a builder even blinks when you ask for references you should walk away.  If they aren’t quick to provide several references, you need to run away.  Seriously.  Why would any good builder not be willing to have you talk to previous customers?  Quality builders love references because their work will shine through.

A really important note: if there is anything at all, that seems not right about any of the references choose another builder. If your gut says something is off, don’t use that builder.  I’d rather be wrong than sorry.

Good builders love contracts, timelines, and references because it improves the outcome and shows their quality work.  Bad or sketchy builders will shy away from these types of things.

Your Turn!

  • What tips do you have?
  • What lessons have you learned from working with builders?

Framing The Floor Of My Tiny House

Today I wanted to share with you all on how I framed the floor of my house. The floors of your house in the floor is made up of a few sections:

  • Trailer decking
  • Sub floor framing
  • Sub-flooring
  • Finished flooring

Trailer Decking:

The trailer decking is the base that you’re resting your sub-floor framing on, which makes up the bottom portion of your flooring system.  Between the decking and the actual framing you want to have two control layers: a vapor barrier and a animal/bug barrier.  For this I used galvanized flashing sealed with a flashing caulking an stapled down.

This helped to block moisture from engineering in, but also kept road debris out.  Additionally this prevents pests and rodents from coming into too, but having a contiguous layer of metal to block them.

tiny house deck flashing

After that I added a single layer of 10 mil poly plastic sheeting as an extra control layer for vapor and air on top of my flashing.

tiny house floor vapor barrier

Tiny House Sub Floor Framing

My tiny house sub floor framing was done with treated 2×4’s placed on 2 foot centers.  The trick to framing is to have all your joists designed to be on 24″ centers, so when you place sub flooring – which is 4 feet wide – you know exactly where to screw into the floor joists.  The other thing you need to consider is the forces that the floor is going to be encountering, this effectively is your foundation, so it’s important for this to be really strong.

tiny house sub floor framing

To add more strength I used corner braces that are used in hurricane prone area building, I also tied the floor joists to the deck of the trailer using high sheer strength screws.  I screwed from below the trailer, through the trailer decking, into the joists.  In certain key joints  I chiseled out notches for the cross members to sit into, this wasn’t in the plans, but I thought the potential forces seemed to call for it.  Here is a video and then a bunch of photos after that.

My Tiny House Floor Framing:

Framing the Floor

 

Framing the Floor

 

Framing the Floor

 

Framing the Floor

 

Framing the Floor

 

Framing the Floor

 

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how much does a tiny house cost