Fasten Insulation With Glue

Mod: Insulated Floor – Part Four

Insulation forms an important part of this conversion and gluing the boards to the floor of the van may not be necessary, it may prevent any future squeaking.

Project Insulated Floor Content

Tie Downs & Wheel Wells
Paper Plywood Templates
Floor Insulation
Fasten Insulation With Glue
Spray Foam Application
Plywood Installation
Hardware & Soft-Ware

What You’ll Learn:

  • Why to glue these boards to the floor.
  • What glue to use.
  • Glue spraying technique.

What You’ll Use:

  • Vacuum/Broom & Dust Pan.
  • Building Paper.

What You’ll Need:

  • One 17.6oz Bottle of 3M 90 glue.

Approximate Duration For This Project: 2 hrs.


Gluing the insulation boards to the floor and walls isn’t absolutely necessary, but it may prevent squeaking and it certainly keeps the insulation in place.
I use 3M 90 as a hi-strength spray glue, that sprays like string confetti and you can buy it in your local DIY superstore. Cheaper versions, like 3M 77 are also available and should do a similar good job. There is a variety of glues, that you can use, but being a spray glue makes things so much easier.
I used one 17.6oz bottle, which was sufficient for the entire floor of my Ford Transit LWB cargo van.

The nozzle can be turned to spray horizontally or vertically and the spray head turns left and right for a wider or narrower spray width. As always, shake the bottle well before using!

Spray both surfaces at about a foot distance and let it dry until tacky. There is no room for error when you put both surfaces together; once in contact, adjusting is not possible.

I used building paper as a background for the insulation to be sprayed, but newspapers work well too.

Gluing Poly-Iso

Gather your tools and materials before proceeding. Regularly shake the spray bottle during the application.

  • Turn the nozzle vertical, to spray from left to right or horizontal, for top to bottom, v.v.
  • Turn the nozzle head around its axle for a wider or narrower spray..
  • Remove the precut insulation boards.
  • Clean the floor.
  • Shake the glue bottle well before using and repeat this regularly.
  • Spray glue on the floor and let it dry for a minute, until it’s tacky.
  • In the meantime, also spray a layer of glue on the underside of the insulation boards.
  • When both floor and boards are tacky, lay the poly-iso on the floor and press lightly.
  • The insulation instantly bonds with the floor.
  • Adjust the spray width constantly.
  • Let dry overnight.

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A job well-suited for even the most inexperienced DIY-er, and one that will not take more than a couple of hours to finish.

The materials for this part of the project, where acquired locally and the total cost was about $12.00.

Other projects of this Van Conversion:

I’m just a DIY’er with a lot of common sense, but with some of the projects, I use some tools and materials, that require you to really know, what you’re doing. Always read the manual and consult an expert if you’re in doubt.

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  1. I’m trying to insulate my Ford transit high top roof. The van is dark red and the roof gets scalding hot. I need heat resistant glue up there.

    1. Hi Tom,
      I can’t recommend a specific ‘heat-resistant’ glue, but you may not need it to accomplish what you want. While I had good results with the 3M 90 spray glue, I would consider a different method of installation.
      With my Medium High Ford Transit, I had to minimize insulation, both on the floor and ceiling of the van, to retain standing height inside. I would use the additional head space you gain in a High Roof van, to add more insulation at the floor level as well as the ceiling. On the floor, I would use a minimum of one inch (up to two inches) rigid insulation, by laying down a wooden framework and fill it with Poly-Iso panels. Topping it off with a 1/2 inch plywood panel.
      The more vulnerable ceiling, could also have a similar wooden framework, adjusted for the curve in the roofline, to which you can attach the ceiling finish material. Both rigid and non-rigid insulation materials can be applied between the roof studs without or with minimal use of glue and held in place by the actual ceiling. Since you have enough height available inside the van, I would use a minimum of three inches of insulation, with the bottom sheet run continuously over the ceiling cross members.
      Let me know, what you decide to do!
      Van Williams

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