Building the sub-floor

Utilizing the corrugation hack to reduce time and cost

Difficulty:

Labor:

15 hours

Cost:

$673.85

We recommend completing the prerequisites before continuing your journey through the steps:

Fan and windows cuts are done. This is recommend that way the metal residue can easily be cleaned out and doesn't scratch or get stuck in the sub-floor.
Sound dampening is installed
Plan for support: Decide on materials and thickness of each sub-floor level – you'll want to make sure you can still stand comfortably given the extra height the sub-floor will add.
- Layer 1 consists of (1) support and (2) insulation
  - Insulation -- (XPS foam board) on the top of corrugations
  - Metal cross beams of equal height to the XPS foam boards that will be the support of where the top wood layers meet and sit on top of
- Layer 2: Wood underlayment (PureBond Birch Plywood)
- Layer 3: Finish
Prior to purchasing anything, estimate how much material you will need:
- Measure width and length of the van floor, ignoring the wheel wells – consider your layout and how far you want the floor to come to the front, back, and side door.
- Using these measurements, figure out what size options your local hardware store has of your wood
- Do the math to figure out how many pieces you'll need

Safety Tips:

You'll be on the floor a lot - purchase some kneepads to help save your knees

We were able to skip the step of filling the corrugations by placing the insulation layer perpendicular across the corrugations. This allowed some additional airflow under the floor, as well saving time measuring and filling the uneven parts of the van floor.

Remove Rust

Before you add your sub-floor you want to make sure you don't have any rust problems. Search your van floor and ensure you do not have rust, if you do - follow the guidelines for removing rust from a vehicle.

Clean, clean... clean

If you were storing anything in your van cargo area, remove it so you can access the bare-metal floor. Get down on your hands and knees and use a cleaning solution - start scrubbing!

Note: Be sure you have the pre-requisites finished before following this guide (you'll want to make sure you have the sound dampening material installed).

Found some scratches?

As you're cleaning, you may notice some scratches on the van flooring or lower walls. Grab some Rust-Oleum and ensure you cover up these spots as they're potential rust problems in the future - especially if moisture is getting caught under your flooring.

Take some initial measurements

Starting from either the front or the back, take complete measurements for the width and length of the area you want your flooring to go. Be sure to include any corners, lips, doors, wheel wells, etc. that you will have to account for when cutting the wood.

Note: We started from the front of the van as we wanted the most solid pieces of wood in the front and not in the garage as that is where we would be most of the time.

Note 2: When taking measurements, be sure to take into account that you'll have a 1" layer underneath the flooring you will be cutting.

Cut your flooring

Once you have the measurements written down, mark your flooring material with the correct dimensions. Now that it's all drawn out, go ahead and start cutting!

Fitting the first piece

Now that you've cut your flooring piece, wipe off any debris and bring it into your vehicle. Gently place it onto the ground and make sure it all of the notches align. If it looks good, move onto the next step... if it doesn't quite fit right - go back and adjust your cuts to make sure it fits how you want it to.

Measurements #2

With your first piece of flooring it nice and snug, measure out from the edge of that piece to where the next piece will go. Again, be sure to include measurements for any corners, lips, doors, wheel wells, etc.

Once the measurements are complete, get cutting!

Fitting the second piece

Once your second piece is cut, wipe off any debris and bring it into your vehicle. Place it up against your previous piece and ensure it fits how you want. If it doesn't quite fit right, make the cutting adjustments that are needed.

And again... rinse and repeat

Continue with the steps above until your flooring underlayment pieces fit into your van how you want them to.

Mark the Flooring

With your wood in place, mark the van walls where there are and pieces touching edge-to-edge. You'll utilize these markings in the next phase when placing the aluminum support bars.

Prime that wood!

Take your wood flooring out of the van and add a coat (or two) of mold and mildew primer. Be sure to let it dry as you work through the next phases of thise guide.

Metal measurements

Remember where you made your markings on the van in the last phase? Grab your measuring tape and measure the distance for each of those marks, van wall to van wall. Write the measurements down as they will be used for cutting the lengths of the aluminum support bars that will go underneath the wood.

Cut the aluminum bars

Now that you have the initial measurements needed, take your aluminum bars and cut them to size. Be sure to file down the edges once they're cut as you don't want to hurt yourself.

Note: Tip the aluminum bars and gently tap them on the ground (or other surface) to get some of the debris out of them - you don't want to track this into your vehicle!

Test fit the bars

Bring the aluminum bars into the van and place them into their associated spots on the floor.

Cut more aluminum bars

Notice that there may be large spaces between each of the bars you laid down. To ensure you properly support the flooring that will go on top of these bars, measure and cut additional aluminum support bars to fill these gaps.

Note: Be sure to add a support bar on each of the ends of your flooring (ie, the front and back of the van).

Test fit more bars

Bring the extra aluminum support bars into the van and roughly place them where they should go to help support the flooring. Keep moving the bars around until you think it works for what you'll need. Once you finalize the placement, hold the bars in place and mark both sides of the bar with a sharpie so you know where to glue them in the future. Also, label the bars so you remember which bar goes into which spot to ensure you don't mix up the sizes later.

Note: We placed additional bars on the ground in places we knew would have heavier items on it, or be used more often, think: water tank, electrical area, seats, fridge.

Assess for overhang

Depending on the corrugations and bar placement, there may be some areas where the bar is overhanging and not being properly supported. Figure out where these are at with your bars and remember the spots. We'll fix them in the next step.

Add support shims

To ensure minimal weak spots in the floor due to these gaps, we recommend adding shims (spacers) to add additional support. When adding the spacers, glue them together using Liquid Nails, and then glue them to the floor where the bar will go.

Note: Be sure to get the thickness the same as the corrugation so the aluminum support bar sits even across your floor.

Glue aluminum support bars down

It's time to glue the support bars into place - get your caulk gun and Liquid Nails ready (also kneepads)!

We recommend putting Liquid Nails down across the van corrugation in between the previously marked areas for the bar. Once you run a line across the entire width of the van, gently place the aluminum support bar into place... and then firmly press down.

After your first one, the next installment of support bars should go much quicker. Go ahead and glue down the rest of them.

Note: Be sure to put the correctly labeled bar in the correct spot :).

Note 2: Liquid Nails Fuze It Max has a powerful initial grab in 10 minutes, and completly cures in 12-24 hours.

Secure the support beams

Given the cure time can take up to 24 hours, we decided to let it rest over night. We added our previously cut wood on top of the support bars and then distrubuted weight to better glue the support bars to the van floor.

Note: In the image you'll notice we didn't coat the wood with primer yet as we were learning the best steps to take :).

Measure and cut foam board

If you haven't, be sure to remove the weights and wood flooring.

With the aluminum support bars installed you can now measure in between each bar to figure out the size of the XPS foam board to install between each section.

Once measured, using a utility knife makes it super easy to cut the foam but don't slice your finger!

Test fit the XPS foam boards

Bring the foam into your van and make sure they all fit. If it doesn't fit, trim it up accordingly. Make sure it's nice and snug against all edges and once that is done, label each of the XPS foam boards for the next step.

Glue the XPS foam into place

Get your gloves and your Gaps & Cracks. To glue the XPS foam board to the van floor you'll need to spray Gaps & Cracks in certain areas. We recommend spraying a line against the edges of the aluminum support bars, on each of the raised corrugations, and along the short side of where the XPS foam will go.

Trim the Gaps & Cracks

Once the Gaps & Cracks has dried, use a utility knife and scrape off any excess foam that may have come up and on top of the XPS foam board(s). The reason you want to remove this is to ensure a level surface for when you place the wood flooring on top..

Add a thermal break

Using your rubberized tape, add a layer on top of the aluminum support bars. If you can, stick the tape on top of the support bars and the foam boards touching that specific bar. This will help keep the foam in place as well as helping with the thermal break.