GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Gluing Polyiso Foam to Metal and Plywood

Brian Keefe | Posted in General Questions on

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 Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. Charlie Sullivan | | #1

    Is your polyiso foil faced? If so, your glue joint is metal-to-metal, so a glue that works on metal is good.

  2. GBA Editor
    Martin Holladay | | #2

    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.

  3. Theodore Chabane | | #3

    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

  4. Deleted | | #4


Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |