I have had several readers email me and other ask me about SIPs as of late: What are they? Why use them? etc. For one reason or another there seems to be some confusion, for some folks at least, so I figured I would talk about them today.
SIPs stands for Structurally Insulated Panels. If we break down this name we have a structural panel, so a uniform part that can be load bearing, and it is insulated.
Here is the basic structure, nothing fancy, but your should get the idea.
So we can see that it is composed of two boards, sandwiching this foam. Now there are not just any boards, they are OSB, which is a type of wood, often treated, that is made of strands of wood glued together with polymers. OSB stands for Oriented Strand Board, meaning the strands of wood are somewhat organized into a particular direction. You do need to be careful if you are wanting to build a environmentally friendly house that is toxic free. Depending on how the wood is treated and what polymers they used to bind the wood, it can gas off harmful fumes or transmit through surface to hand and hand to mouth. So just remember to ask what they are using.
Next let us talk about the foam. The foam is a very special mix that has to be cured under very specific conditions. The foam is Rigid Foam Core , very similar to that of foam found in bike helmets. The panels typical come in variations of 2 inch thicknesses (so 2″, 4″, 6″) and have some really nice properties. Inherently the foam used is also a vapor barrier, this of course means it servers as stop from water infultration. It inherently also does not mold and is not liked by most bugs.
There is a few really important things I want to point out with SIPs. The first being that it replaces studs, you do not build walls, you simply put these in place. The second thing is that you now have to run the wires differently, because you can’t run wire in a pre assembled panel. Finally SIPs are prefabed then brought to the site, this cuts down on over all cost.
Some other benefits can be found here: click