Making Homemade SIP (insulated panels)

[Anthony Whitesell]

OK well not exactly a SIP, but I need to adhere XPS insulation to plywood. What adhesive will work? I have some epoxy on hand that I was hoping to use. I will try it unless some knows that it will react.

[Paul F Franklin]

Any good construction adhesive works well. I use PL Premium; it's compatible with most foams. I've used a lot of it with XPS. It takes a while to set up, so the foam may need temporary support to keep it in place, depending on whether it's horizontal or vertical, etc.

Epoxy will probably work, but seems like overkill. Fast setting epoxy can generate a lot of heat, so that may damage the foam even if the epoxy doesn't dissolve or soften the foam.

[Mike Kees]

Use the PL product made for foam , I think it is PL300 .

[Mark Bolton]

I agree with mike with the PL 300. Most of the urethanes will eat the foam if its raw. I believe epoxy will eat it as well. An outdoor rated vinyl mastic (waterbased) would be better than the PL300 though because you will need a ton of tubes if your doing a panel of any size. We laminate hardboard to XPS both sides and use mastic with a notched trowel. We've used the PL300 a few times but it takes almost a case of tubes to cover a 4x8 sheet with a notched trowel and that gets super spendy.

[johnny means]

We literally made hundreds of these for use as trade show walls. PL was the adhesive of choice. Like mentioned earlier, it doesn't go far, so it does get expensive. We didn't bother with toweling, just a 2x4 square grid drawn on each panel.

[johnny means]

Contact adhesive also works well. Though, if you use a solvent based adhesive it must be sprayed on using multiple light coats.

[Mark Bolton]

For a non structural panel dabs or grids of adhesive would be fine. We stick xps and iso on walls like that all the time but for a SIP or in our case we machine the panels after so 100% coverage is necessary. Depending on how many it may be worth buying a DIY foam kit and building a quick form and spray filling the core. Youd get a better panel, no adhesive, and higher R value.

[Dave Lewis]

I also used Loctite PL 300. Just make sure you / or props need to apply pressure during application.

[Anthony Whitesell]

3M Spray adhesive works well too. Read the can. Works on foam. Tried it on a test piece and didn't melt. Project is complete. Thanks all.