When shopping for SIPS , verify that panel mfg. does not use "re-grind" foam.

It is also better to use 1# minimum density instead of 1# nominal

We see tons of "re-grind" coming back across the border into El Paso and folks who manufacture SIPs to ship back into Mexico use it. But the de-lam problems are scary. We manufacture the glue they use and have seen the tinsel strength decrease considerably with this foam.

Any foam used should be, at a minimum, rated in accordance with certification guidelines and most of us as manufacturers use them. We would compromise our testing and certification to do otherwise. Buyer beware and be proactive.

Greg;

Exactly!  re-grind is good packaging or insulation that is not used in a structural laminated panel.

just as a 2 x 4 is no longer 2" x 4" it is "nominal" actually being 1-1/2" x 3-1/2"

the same is for 1# "nominal" density foam it can be as little as .90#

The problem we see is an inconsistent size and an inconsistent melt of the recycled EPS. It is not binding in such a way as to ensure a good strong bond. And that's a weak bond of both the EPS and the glue bond of EPS to OSB.

We have tried a hybrid glue to accommodate these problems but have found no solution. It is just a substandard product. If 1# is 3.84-3.85 R-Value, then we can assume the recycled, re-grind, is going to provide an inconsistent R-Value as well.

For me there are enough naysayers already trying to buck the SIPs upswing, all we need is the introduction of a substandard EPS to fuel their fires.

Greg;

you are certainly right, I know there is at least one company out there indiscrimanantly selling "Jumbo's" with regrind, it looks like tightly packed popcorn. It is one of those accidents waiting to happen, especially when price is the main goal of the purchaser without regard for end use.

We prefer Type VIII - EPS, which is 1.15 to 1.34 lbs. density per cu ft., it also obtains the greatest bond.