Well I recently was introduced to sip construction from a co-worker. I am looking to build a garage/shop, hoping to hit 24x32 at 10' tall may do 9' to save on money. I have received a couple quotes for conventional and sip so I am at an understanding of cost. I have been researching and looking for better information on the actual construction of the sip panels. Looking for Lbs/cubic ft for the EPS foam used, osb thickness, the adhesive used to bond the two together. and any other information that is important for the structural integrity of sip construction I currently have 8 blocks of 1lb eps foam, I use this foam to build surfboards and other items. The 1lb foam was a given to me from a previous employer so if I were able to use it to build my own sip panels that would be awesome. I am thinking I would do the walls in sip and a conventional roof system. yes no? I have a good understanding of eps foam. I personally don't feel that 1lb eps foam would be a very structural product, for this application, even thou an adhesive could be applied that would bond permanently to the wood and the foam, the 1lb foam can still easily be torn from itself. I see a few ways to prevent this from happening, but if they are using a higher lb foam I will probably just pass on this idea. The foam I have is the same foam you would bury in the ground around your foundation. thank you in advance for your insight.

Hi Tuf, this topic comes up now and then. There is a big difference between DIY installation of SIP panels and DIY construction of SIP panels. It's not advised to make your own panels, because of the potential for disaster as a result of structural failure.

As you have observed, the foam itself is not structural. The OSB alone is not structural in this application. It is the combination of this sandwich of skin, foam, and glue that creates a structural panel capable of more than it's individual components could achieve by themselves. If you get some component of that equation wrong, for example the amount of pressure applied to the sandwich as the glue is curing, then it's not going to function properly. The other thing to consider is that you will never get a permit for homemade panels.

If the quotes between conventional framing and SIP construction seem too far apart to you, then are you sure you're making an accurate comparison? Is the conventional framing insulated? And if yes is it insulated with fiberglass batts? How much will you save in energy costs? And are you in a zone where the sturdier SIP construction will make your shop safer in weather events?

If you want to go DIY and make use of your foam then you might consider going with conventional framing but applying the foam outside the sheathing and properly detailing it underneath the siding.

thanks for the response Jelly,

the quotes I had should be pretty accurate. it is a little over $2,000 difference for materials. However, like you stated the energy efficiency and the time to build it all would be much better and faster with SIP construction.

I was more interested in knowing the lb of foam that is used, because if they are building these walls with 1lb foam the process really cant be all that technical, and I would imagine that a top and bottom sill holds a lot of the strength along with some other aspects of the build. When they do larger sections than 4x8 is when fancy machines and what not would basically be a must, in my opinion.

it is all pretty neat, I am still curious of what lb eps foam they use and unless others have been successful in building their own panels I don't think I would try.

One-pound foam is typical.

Home-brew panels come up as a topic now and then, and some of the threads devolve unfortunately into a very unpleasant back and forth. This results perhaps from a basic misunderstanding of the engineering behind a SIP structure. Needless to say I haven't heard of anyone succeeding with making their own panels.

But if you've got a lot of foam available to you I think you can definitely put it to good use in other ways.

Simple if you shop Sips can be had for about $4 a sq ft.

Do you calculations with that number for comparison, you can't build your own panels near the structural capacity of a sips manufacturer that compresses the sandwich.