Gluing Polyiso Foam to Metal and Plywood
![](https://secure.gravatar.com/avatar/03f2c8b2ec3439eb5b750f8d87c0461f?s=52&d=https%3A%2F%2Fimages.greenbuildingadvisor.com%2Fapp%2Favatars%2F200x200%2Fb.png&r=g)
Hey everyone –
I’m planning to convert the floor of a van, adding polyiso insulation and plywood
My question is about the best product(s) to use – I’d rather not screw the plywood into the van floor so glue will have to provide all the needed support (and survive through all of the vibrations and bumps)
First layer: 1/2″ polyiso, glued to the van floor (metal)
Second layer: 1″ polyiso glued to the bottom polyiso layer
Third layer: 1/2″ plywood glued to the second polyiso layer
So far considering 3M 90, The Great Stuff, and / or the Loctite PL300 Foam Board Adhesive
Let me know what you think – thanks!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
![](https://www.greenbuildingadvisor.com/app/themes/greenbuildingadvisor/dist/img/modules/detail-library/thumb1.png)
![](https://www.greenbuildingadvisor.com/app/themes/greenbuildingadvisor/dist/img/modules/detail-library/thumb2.png)
Replies
Is your polyiso foil faced? If so, your glue joint is metal-to-metal, so a glue that works on metal is good.
Brian,
My guess is that a canned spray foam adhesive might stand up better to road vibrations, expansion, and contraction than a metal-to-metal adhesive. But I'm not an expert on this type of work, by any means.
You might want to post your question on a forum focusing on van conversions.
Dear Dr. Holladay,
We're in the process of designing a house such as your's, rafter overhangs applied after the self-adhered membrane ( Vaproshield). Rather than use Roxul outboard, we have access to 4"to 7" thick sheets of polyiso. Although Iso-clips will be the primary weight/force resisting attachment we would also like to glue the polyiso to the membrane.
Any thoughts on this configuration?
Best regards, Ted Chabane
Deleted