Tiny House, Tiny Living, The Tiny Life.

Tiny House Sheathing

Playing catch up with the posts about building the house.   I went and ordered my sheathing for the walls and roof.  There is a newish product that I am using called the Zip system.  (zipsystem.com)  Basically it is wall and roof sheathing with the house wrap/roof felt already on it, which is pretty fancy.

It also has these little nubs on the edges so you don’t have to worry about expansion gaps like you would with traditional sheathing.  Along with the spacers, the board is printed with markers so if you do your walls correctly, you can just follow the guide on the boards and you hit a stud every time while securing it from the outside where you can’t see where the studs are.  The kicker is that not only does it have some major time and labor saving factors, it costs a lot less!  You have to use their special tape, but its about 1/2 the price of tyvek tape, so that isn’t a big deal.

photo

I priced it out and its much cheaper and then you don’t have to spend all that time house wrapping.  The vapor barrier on the zip panels does the exact same thing as tyvek, but its more durable and isn’t prone to being pulled off by inclement weather.    It also apparently makes a much better air seal and is LEED Credit Certified.

 

Traditional sheathing: 18 sheets @$28
Tyvek Wrap: 1 roll $150
Tyvek tape: $100
Roof Felt: $19
Capped Nails: $7
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Total: $780

zip boards: 12 @ $19.50  and 6 @ $26
Zip Tape: 2 rolls @ $27
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Total: $444.00

Me happy about saving money and getting the sheathing done!

Me happy about saving money and getting the sheathing done!

So when it comes to sheathing (which is what the plywood on the outside of the house are called) the trick with it all isn’t the actual plywood, but that you did your framing correctly.  If you have done your framing correctly, then the seams of each of your pieces of plywood will land right on the stud.  This is important because you need to be able to nail the edge of the sheathing to that stud.  There will be some cases where a panel lands on a window, so you will need to place an extra 2×4 piece to have something to nail into, you can see below an example of this.

photo 1

This photo also shows how in tiny houses we screw and glue our sheathing.  Here I used liquid nail on the studs.  A piece of advice for anyone who is doing this, help yourself and spring for a air powered caulk gun.  I tried to do this for one day and by the end of it I swore I gave myself arthritis because how hard you have to squeeze this stuff.  They have a lot of better powered caulk guns for $150-$350, but this gun is $35 and well worth it.  To give you an idea of how much you’ll be doing this, I went through about 40 tubes of this stuff while building my tiny house.  As far as fastening the sheathing, I used 2.5″ exterior grade screws, every 6 inches on the edges and 12″ in the center (field).

In the video and some of the photos you can see that the sheathing is actually larger than the wall frame.  I had the sheathing extend below the wall framing to hide the trailer so that you’d really only see the tongue and fenders, the rest of the trailer is hidden behind, once finished, nice looking cedar siding.  I also had it extend above the framing because I could wanted the sheathing to tie into the loft beams, flooring of the lofts, and the silplate.  So I carefully calculated the height of all the components listed and a few others, so that when I installed the silplate (that the roof rafters sit on) it was perfectly flush.  This

The other key thing to know about the overhang and extension was that this then tied all three systems together to be a very strong unit.  Effectively the floor framing, the wall framing and the roof became a unified piece because they all were brought together by the sheathing.

photo 3

photo 4

14 Comments
  1. Im not sure where you live but your material prices are completely backwards …… 7/16″ OSB (which is more than enough for a tiny house!) at Lowes is right around $12 NOT $28 ……. 1/2″ 4×8 Zip OSB is around $30 a sheet

    18 sheets of 7/16″ OSB is around $216 not the $500+ you stated ….
    And ZIP panel is around $576 for 18 sheets …..
    And those are the current prices right now on Lowes.com nationwide website ……

    • Hey Dave,

      I just pulled up the prices for those 7/16″ OSB sheets you mentioned and they are $8 here locally for Lowes, so obviously there is a big difference in prices depending on the location. When I got these prices, which was about a month or two ago, I was looking at 19/32 OSB Sheathing which is going for $22 right now at Lowes. I also used 5/8″ on the roof which was able to get cheaper than the other OSB equivalent.

      So it sounds like location impacts the prices a lot and also know that I used thicker pieces than 7/16th.

      • YES the prices do fluctuate but 19/32nds” for roof and wall sheathing isnt need at all for these little houses ….. 7/16″ horizontal is more than enough for strength and weight reduction also

        • The Sheer Schedule from my plans stated that I needed the bigger thicknesses and that the boards should be oriented in that way. That schedule was determined by a structural engineer, so I decided to go by their directions because they are more qualified than I am in those areas. I know that doing it horizontal would make things stronger, but the plans specifically had the panels in this orientation, so I went with that. I think its because then you can tie the the floor framing in with the sil-plate.

          I wonder, in a traditional home, since it’s too tall to span floor framing to sil-plate with one sheet, so is a horizontal staggered board the next best thing? Maybe not though, I’ve seen some figures on the horizontal vs vertical boards, the numbers seem to add up in favor of horizontal. Conversely not everyone (maybe not most) don’t glue it like tiny houses do, so I would think (just a guess though) that the glue + screwing would at least approach the same strength as horizontal boards, but with the added benefit of tying in the floor, wall, and sil with one board. Thoughts Dave?

  2. AND if you really want to add rigidity and strength to the home try running your sheathing horizontally instead of vertical and stagger the joints >> then you wont need a billion screws and 40 tubes of adhesive >>>>>> Also try a 7/16″ crown air stapler for fastening the sheathing on the studs ….. Just as strong as those screws and 1/2 the time to do

  3. Hi Ryan,
    Loving the new pictures, and interesting comments by all. I’ve never heard of the Zip system, and am going to check it out. Looks much easier than separate sheathing and wrap, but I’m sure it’s very much a risk for off-gassing….
    I’ve been thinking a lot about the whole sheathing/wrap issue for days, and your post is very timely.
    Nice work :)
    Parker

    • Hey Parker,

      You really should be using treated OSB / plywood for this stuff because of how close it is to the outside layer. I’m not keen on the stuff, but there are benefits to it. Most of the off gassing will occur in the first month or so and being that I have taken my time with this step, the bulk of the off gassing has already happened before I close up the walls.

      There are some alternatives, but nothing that really stands out as viable or having reached market. I did find this paper which shows that brand new boards can’t exceed .2 parts per million of off gassing at time of manufacturing. I feel pretty good about .2 ppm and add in a month of time to off gas, I feel even better.
      Paper: http://www.chimarhellas.com/wp-content/uploads/2009/10/athanassiadou-tsiantzi-markessini-paper-2.pdf

      The other thing to consider is that these boards are on the outside of your house, you’ll have quite a few layers between you and it. Certainly something to consider.

      Another good link: http://www.professional-laboratory.com/product_43.html

  4. Ryan, Just a hint with the calking gun, you are going to be using that many times in the future, even for preventative maintenance. Try cutting the tip a little closer to the end and cut it square, not on the angle everyone seems to think is the proper way. (is that angle printed on the directions, stupid if it is) Depending on the adhesive, more is not always better but more difficult to work with and has some detrimental results.

    By cutting the tip square, you will be able to see a little or as big a bubble you want ahead of you all the time regardless of the direction you are travelling (if you get to a corner, and want to come back in the other direction, this works great) and with very little practice you will see the benefit of the square cut. If you’re not getting enough product, cut it back a little further until you are comfortable you are getting even displacement and by cut it back I am talking about a 32nd at a time, when I first cut the tip on the tube, I can just get the little probe or coat hanger rod in the hole, for calking baseboards and filling trim cracks, that amount is perfect or just shy of enough to do the job, just shave your cut back if that’s not enough and if you need more, shave it again.

    It’s pretty common to see those high (the clumps) or excessive places where you squeezed the trigger; those can give you a bit of difficulty flattening the sheet to the stud and could result in access points for moisture behind the panel, it only takes a pin hole. That little trick gives you full control over the amount you are putting on and you will find it cleaner to work with. I would love to have seen your hands when you finished that day.

    The objective of installing an “effective seal” is met with ease and a power or air gun is not required. Doing it by hand gives you full control and you won’t be squeezing it 10% of the time you did here. As dear old granddad used to say, don’t blame the tool bud, learn how to use it. (I hated hearing that “lol” but he was a craftsman)

    Sounds like you have a good tutor in Dave and his point on the 7/16″ crown air stapler for fastening the sheathing on the studs is one I would take, I also have an air pin nailer, I use for a 3rd hand or when doing mock ups. Easy for “by hand pulling apart” and no or little scoring on wood. I get impatient and want to see what it looks like up so do many mock ups. You sound like me with a screw gun, I use it far too often but over the last few years have started using the pocket hole screw system and when you are doing your interior, have a look at that, “turns a want to be into a doer”. http://www.kregtool.com/pocket-hole-jigs-prodlist.html the basic kit starts around $100.00 but by the whole kit, everything they have to offer, you will be happy you did. I had a 10 bedroom rooming house and built all the furniture with one of these in no time at all and I am far from a competent finish carpenter or cabinet maker. YouTube will show you how versatile this is and a novas can be as good as the instructor, I know that for sure.

    I am not a novas with a calking gun thou so defiantly try my advice with that. 40 tubes, oh Ryan, you have too much money LOL, can’t tell you how many times I did the same thing until my brother in law showed me this.

    • Hey Ralph!

      The “clumps” were intentional, I would go a few inches, then pause a second, then go again. But to your point/advice, I might want to use a more consistent bead. The air gun I have is very consistent in the rate it pushed the glue out, but I’ll give your tip about cutting it square next time.

      I actually picked up one the kreg kits for the interior over the holidays, it’s awesome!

      With the staples there seems to be some contention on those vs screws vs ring shank nails. I heard, don’t know if it is true, that Florida doesn’t allow the use of staples and I have looked to their standards on a few occasions because they are geared to heavy storms and their wind considerations are similar to towing a tiny house down a highway at 60mph. Thoughts?

  5. Lookin’ good! Instead of Liquid Nails we used PL 375 on everything. That stuff is amazing! You can glue anything with it. Can’t say enough about the importance of high quality screws and adhesives.

  6. Doesn’t off gassing have at least 3 steps?
    – at point of manufacture
    – at use
    – dispersed

    While the products that you don’t want to inhale may leave your immediate area they don’t go “away”. Consider the people who work with these products every day, the waste produced and the ultimate fate of these products.

    • That’s exactly what I worry about. I’ve been wracking my brain to find both sheathing and the indoor wall covering that is neutral/natural. I don’t want to take over the comments section, but my search for natural, safe, lightweight and strong materials for those two important components has been rocky.

      I’d appreciate any thought or ideas.
      Parker

  7. Looks like an interesting system for those who do the sheathing and siding option but it looks like a lot depends on local pricing. I was hoping to just get away with a combined sheathing/siding using T111 (the properly rated stuff)and update with a rain screen covering in a year or whenever I save up enough money for it but that may change. It’s always good to learn about these new things from somebody that’s used the stuff in real life. I tend to disbelieve a lot of the bumf on company websites. It may or may not work as stated there but they sometimes don’t point out problems that actual users run into. Sometimes a good outcome depends too much on a perfect installation which isn’t always as easy in the field as in the lab.

  8. Horizontal sheathing is quicker and probably better due to needing blocking at 4′ joint to meet shear specs. Screws aren’t necessary when gluing panels.just nail them with a 2-3/8 full round .or a ton of staples are fine too . From what I read on these tiny houses is over build to ridiculousness. I have a 1958 shasta trailer talk about cheap framing still together.

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