Floor Insulation - Cutting Poly-Iso

10602 Views 13 Replies 9 Participants Last post by mdem1989, Apr 15, 2020

cargovanconversion

Discussion Starter · Jun 13, 2016

I've been meticulously documenting my van conversion as a reference tool for others, for them to know what every little step of a conversion really means and whether they might be able to do it.
Currently I'm working on the sub-floor and have just published part three of the installation.
I've been laying poly-iso boards between the ribs of the floor of my Ford Transit.

You can read about all the details, see photos and view the video here.

Or part 2: Paper Plywood Templates
Or part 1: Tie Downs & Wheel Wells

Enjoy!

Van Williams

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cargovanconversion

Discussion Starter · #3 · Jun 13, 2016

Not having seen the 2017 model yet, I doubt whether Ford will make any changes to the floor. My experiences with my 2016 T250 LWB MR are that the metal used in the walls, roof, floor and doors are relatively thin (probably because of weight restraints). The ribs in the floor (and roof) give more strength to the structure.
Because I have a medium high roof, I choose to fill up those 'rib cavities' with poly-iso and not compromise the standing height inside the van. Some fill it with plywood strips with insulation on top followed by the underlayment.

Have fun with your conversion and post some pictures if you can.

Van Williams

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cargovanconversion

Discussion Starter · #5 · Jun 13, 2016

rene12341 said:
What is the height of the ribs compared to the surrounding floor?

Slightly less than 1/2 inch. I put 1/2" poly-iso in between and filled up with a spray foam including some on top of the ribs.

Van Williams

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cargovanconversion

Discussion Starter · #11 · Jun 14, 2016

Hein said:
Is there any concern for squeaks with the hard foam under the floor? We prefer minicell closed cell polyethylene to fill the ribs and then a full layer. Minicell is used under dance floors for comfort and noise reduction.

As with all things, it's a balance between wants, can do's, price, properties and feasibility. I have no experience with the closed cell foam, but it will very likely have less issues with squeaks. In general I haven't heard of any major issues with poly-iso which is also much more affordable with afaik a higher R-value. In my case, I'm working with a medium roof Transit where I barely have an interior standing height available. Putting on an extra layer of insulation, may just compromise the height issue.

Van Williams

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cargovanconversion

Discussion Starter · #13 · Jun 15, 2016

First of all I don't have Ford's black plastic flooring, so I cannot advise you on that, but I'm sure someone else will be kicking in and give you an answer on that.

I think Poly-Iso is perfect for this application. You don't often hear about squeaking, but just in case, I use the spray glue for that. I wouldn't worry too much.

(My) Common sense tells me, that long term the chance of sagging is likely to happen and that will cause the entire floor and everything on it to move. Yuck. Whether it's wood, insulation or an other material, I would seriously consider to fill these voids.

Reusing Ford's plastic floor is a good idea and if you have a high roof model or you are very short, a full sheet of Poly-Iso on top will give you perfect insulation. I have a medium roof and have not much interior height to spare, so I reluctantly left out this step.

The 5mm ply depends on your application. I used ½ inch plywood because I want to secure all the cabinets to the floor. I even prefer ¾ inch ply, but the extra weight is also a consideration.

It's probably not the perfect answer, but you catch my drift?

Van Williams

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