Installing a floor in a van conversion is one of the first projects that you’ll need to tackle, as it’s the base for many future projects. Our approach will include a layer of polyiso insulation, plywood and vinyl flooring.

Material, Tools, Cost & Labor

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[ebs_toggle active=”active” ocicon=”true” title=”Parts & Material” icon=”fa-gears” icontype=”fa” iconcolor=”#ffffff”]• 3 sheets – 1/2″x4’x8′ Exterior Grade Plywood
• 2 sheets – 1/2″x4’x8′ Polyiso
• 3 sheets – 1″x4’x8′ Polyiso
• 8 – 1/4-20 x 9/16″ Teenuts
• 8 – Grade 8 1/4-20 1-1/2″ Hex Bolts
• 8 – 1/4-20 1″ Stainless Steel Fender Washers
• Locktite
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[ebs_toggle active=”active” ocicon=”true” title=”Tools” icon=”fa-wrench” icontype=”fa” iconcolor=”#ffffff”]• Jigsaw
• Circular Saw
• Socket Wrench
• Hammer
• Drill bits
• Tape Measure
• Black Marker
• Large ruler
• T-square
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[ebs_toggle active=”active” ocicon=”true” title=”Cost & Labor” icon=”fa-clock-o” icontype=”fa” iconcolor=”#ffffff”]Total Project Cost: $TBD
Installation Time: 8 Hours[/ebs_toggle]
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Process

Step 1: First Layer of Insulation

We have a high roof Ford Transit so we have more than enough vertical space to install an insulated floor. We started our floor insulation with a layer of 1/2″ polyiso in between the floor ribs. Polyiso has an R value of 6 for every inch and can stand up to the pressure applied from walking on it, especially when dispersed across a larger area. Installing the polyiso is an easy process as you only need a large blade, tape measure, ruler and writing utensil.

The factory floor ribs are just shorter than a 1/2″ so the polyiso fits nicely between the ribs. Once the additional layers are installed and the floor bolted down it will compress the 1/2″ polyiso slightly before the top layer rests on the ribs. This will hold the polysio in place. We eventually chose not to use an adhesive to hold the insulation in place as the clamping strength of the sub-floor seemed to be enough. If we ever wanted to or had to remove the floor we wouldn’t be stuck with dealing with the adhesives. Time will tell if this will cause issues down the road.

Working from one side of the van, we began measuring the areas between the ribs and translating the dimensions to the polysio. Using a large extendable box cutter made short work of the polysio. Most the pieces are long straight cuts and can quickly be completed. Sections near the wall will require a little more time to stencil and cut around columns, wheel wells and smaller sections of independent ribs.

On our 148″ long-wheelbase Ford Transit we needed two 4’x8′ sheets of polyiso to completely cover the floor.

Step 2: Second Layer of Insulation

On top of the 1/2″ polyiso is a layer of 1″ polyiso. We used 3 – 4′ x 8′ sheets to cover the entire floor of the cargo area. We used the factory rubber floor mat as the basis for the template for cutting the foam. The factory rubber floor mat does have some cutouts that you should not use as is. Before tracing the floor mat exactly you should look at how the mat fits in the van and around all of the walls. Make notes of where the floor mat does not cover the floor fully so you can make the necessary corrections when tracing it to the foam.

After tracing the floor outline to the 3 sheets of polyiso, we cut the pieces out with a large extending box cutter. I cut the foam out with an extra half-inch beyond the outline of the factory floor mat to allow for a tighter fit and additional adjustments once installed in the van. Each sheet was installed and then additional pieces were cut or shaved off until the ideal fit was found.

Step 3: Installing Wood Sub-floor

Since each piece of the 1″ polyiso was cut and proved to fit well we removed it and used it as a template for the sub-floor plywood. We repeated the basic process from the polyiso. Trace, cut, install. We made note of the overlap between the played and the polyiso so the seams would be staggered to help prevent the floor seams becoming uneven in the final floor.

Once traced we used a circular saw and jigsaw to cut out the plywood. Each sheet was fitted and a few additional cuts were made to make a close but not tight fit against the edges of the van. If it’s to tight then you run the risk of causing squeaks when driving down the road or walking on the floor.

In an attempt to prevent future moisture issues from becoming problems we gave the sub-floor plywood a solid coating of shellac on both sides.

We secured the floor using counter sunk teenuts and Grade 8 bolts inserted from below van into the floor. We drilled holes through the sub where the raised floor ribs were. This allowed us to use 1.5″ bolts so when tightened the threads did not raise above the floors height. Allowing for an easy installation of the final vinyl flooring.

We painted the drilled holes of the metal floor to prevent rust and sealed the holes with silicone during the final install.

Our Experience

Installation Process

Installing the polyiso insulation is really easy. The only challenge with the polyiso is once you’ve installed it you have to be careful when installing the subfloor. I was installing the sub floor by myself which is not advised. Trying to lift a sheet of plywood into the back of a van without any corners stabbing a hole in the foam is a challenge.

Performance

So far we are squeak free and the floor feels really solid. We’ll need to take a few more trips and finish the rest of the build and lower cabinets to see if the added weight becomes a problem with the foam insulation.

In Retrospect

The only things we would’ve done differently is being slightly more precise with the 1″ polyiso around some of the pillars and having a second person during the subfloor installation at all times.

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