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Skoolie Subfloor | Options, Floor Prep, & Install Guide

Skoolie subfloor is one of the first things you will have to tackle after demoing your bus. In this article, we will go over different skoolie subfloor options, prepping for subfloor, and subfloor installation.

The Best Skoolie Subfloor Options

The best skoolie subfloor is subjective since it depends on different factors on how you will use your skoolie.

  • Full-Time Traveling vs. Parked: If you plan on traveling full-time in your skoolie, you will want to make sure your floors are fully framed out. This will help keep the bus rigid. If you plan on staying parked or not moving the bus at all, you may not need to frame your floors out or frame them out only slightly.
  • Warm Climate vs. Cold Climate: If you are going to be traveling into a cold climate a lot, you will want to be sure to insulate the floors. If you plan on traveling into a warmer climate, you might not need to insulate the flooring or insulate thinly. With that being said, if you are going to travel in extremely hot climates, such as Florida insulation would be highly recommended as well.
Skoolie spray foam insulation

We took it upon ourselves to do some digging through different ways you could install your skoolie subfloor.

In the rest of this article, we’ll go through how to prep for the skoolie subfloor, different ways to do your skoolie subfloor, and the subfloor install. We’ll also go through some subfloor tips we picked up along the way.

Special Note: This article does have affiliate links. If you click a link and happen to make a purchase, we may receive a small commission at no cost to you. Thanks for your support – this commission helps us to continue educating the skoolie community!

#1 Skoolie Subfloor Prep

skoolie subfloor rust converter

Prepping for your skoolie subfloor is just as important as installing the subfloor in your skoolie.

You will want to make sure you address any rust with a rust converter and then paint it with Rustoleum paint. Even though we only had a few patches of surface rust, we used the rust converter over the entire floor of our bus.

If you are like us, your bus may have holes in the floor that you need to cover up from demoing your bus.

skoolie subfloor prep

We covered the holes in our floor with scrap sheets of sheet metal and quite a bit of silicone to make sure everything was sealed.

After the floors are addressed for rust, painted with Rustoleum, and the holes are all covered up, the skoolie subfloor prep is done! Now, let’s get into how to install the subfloor in skoolie and the different options you have when completing this step.

#2 Skoolie Subfloor Options & Install

Fiberboard, 2×4’s Framed in Pink Sheet Insulation, & Plywood
(what we did)

We figured we would start with what we did for our skoolie subfloor since we feel like it has really held up after 2 years and we feel we did everything possible to maximize our skoolie subfloor.

We started with Blue Ridge Fiberboard. It’s a premium insulating sheathing that has sound deadening capabilities and allows the floors to breathe which reduces mold threat. We personally didn’t want to put wood directly on top of metal because of the thermal radiation. If we put the wood on top of the metal floor, we would get cold feet in winters and very hot feet in summers.  So that’s why we went with the Blue Ridge Fiberboard.

The fiberboard is “floating” on our floor, meaning we did not use any liquid nails or adhesive to attach this to our floor. It is just set down on top of the painted metal floor.

We then framed out our floor with 2x4s. We strategically placed the 2x4s to aid in supporting all our built-in furniture, such as the kitchen cabinetry, the couch, and the walls we included in our bus. We recommend understanding your skoolie layout before placing the 2x4s down if you are going to do it this way. In doing so, think about where your aisle will be along with your couch, dinette, kitchen cabinets, and bed. This will help you to know where to place the 2x4s for added support.

Do you have to use 2x4s?

No, you do not have to use 2x4s. We did because we wanted our floor to be really supported and not allow for any dipping in the floor. We also wanted to get 1 1/2″ pink sheet insulation (R-7.5), which you could also use if using 2x3s. If you did not want to take up valuable headroom, you could also do the same method we did with 1x2s then use 3/4″ thick pink sheet insulation.

We definitely overdid the amount of 2x4s we have on our floors. But we wanted them to hold up and since we have a center aisle, we knew that that’s where we would always be walking so we put a ton of supporting 2x4s there so the flooring didn’t squeak when we walking on it and we didn’t want it to dip either.

So when placing the supporting 2x4s, think about where your aisle is going to be so you can put a few extra boards there as well as supporting the more heavy items in your skoolie, like your couch, kitchen cabinets, refrigerator, bed, etc.

Then cut up the pink sheet of the same height to the supporting boards you are using to fit inside the framed 2x4s. We used a sawzall to cut this up but there are much better options out there for cutting the pink sheet. Using a sawzall created a lot of dust and did not give us clean edges. A long utility knife would be easier and give you cleaner edges.

Secure the 2x4s with liquid nails to the Blue Ridge fiberboard and that’s it. No screws just yet.

After all of the 2x4s are glued onto the fiberboard and the floor is insulated with pink sheet, now it’s time to lay the plywood on top of all of this. The thickness of the plywood depends on how much headroom you are wanting, be mindful of this when choosing plywood thickness.

We screwed the plywood down to the 2x4s we laid down. So we ended up with the floor being a “floating floor” with the plywood underneath our finishing flooring being attached to the framed 2x4s.

The way we completed our skoolie subfloor is what we would recommend to everyone converting a school bus. You get a thermal barrier, you have sturdy supports for framing out the interior of your bus, and you have insulation. Below we have outlined a few more ideas that could be done, depending on your situation.

The Good

  • Has a thermal barrier break from the metal floor
  • Resists mold
  • Sound deadening
  • Completely framed out floor
  • Won’t allow for dipping in the skoolie subfloor

The Not So Good

  • It’s adding at least 2″ to the overall height – fiberboard (1/2″ thick) 2x4s (1 1/2″ thick) which takes away from headroom.
skoolie subfloor

Fiberboard & Plywood

Another option is to do the floating fiberboard and then lay the plywood on top of it with liquid nails, no 2x4s or insulation here.

This option will still give you great sound deadening, breaks the thermal barrier, and maximizes the height inside the bus.

If you plan on staying in a climate that isn’t too hot or too cold, this may be the right option for you. We recommend adding insulation to the floors almost always. If you are going to be parked in a climate that stays about 60-70F year-round, you may be okay with not adding insulation to the floors. However, if you want to travel to colder or hot climates, we would recommend adding insulation to the floors.

The Good

  • Sound deadening
  • Thermal barrier break form the metal floor
  • Resists mold
  • Leaves ample headroom space

The Not So Good

  • No insulation
  • No sturdy framing

2x4s Only

Like I said earlier, you don’t have to use 2x4s, you can also do 1x2s or 2x3s. 2x4s give it much more support. The 2x4s or supporting boards laid flat will determine the thickness of the skoolie subfloor and the thickness of the insulation directly touching the floor. With flooring insulation, you could either use pink sheet or spray foam insulation. Read more about insulation here. Top this off with plywood.

While this is an okay option and gives you added insulation, we don’t recommend this option as the 2x4s or supporting boards can potentially bring the heat or cold through to the plywood. If using pink sheet, this will directly be touching the metal floors which could cause a lot of noise when walking on the floor after your bus is done.

With there being no thermal barrier and have the potential of noisy floors, we would not suggest this option.

The Good

  • 2x4s to mount to
  • Good insulation

The Not So Good

  • Possibility of noisy floors
  • No thermal barrier

#3 Skoolie Subfloor Tips and Q&A

Plumbing, Electrical, & In-Floor Heating

When you are completing your skoolie subfloor that is the best time to run any plumbing that needs to be ran to both sides of the bus. If you are only having plumbing on one side of your bus, good for you, that is the easiest way to do a skoolie in our opinion.

Electrical wires will have to cross over to both sides of the bus at some point. In the floors is definitely the easiest versus thick wires going across the ceiling. We ran a PVC pipe filled with wires in the front of our bus in the floors to connect both sides. We would also suggest running extra wires just in case you want to add something extra later on down the road.

In-floor heating is something else you would want to think about at this stage. Obviously, this is a luxury and not at all “necessary” but how nice would it be to wake up to heated floors on a cold morning?!

What screws go into the steel floor?

We recommend doing a “floating floor” meaning what you lay on the bottom is either floating (what we did with the Blue Ridge Fiberboard) or using liquid nails to secure it to the steel floor. Try to keep holes in your floor to a minimum, after all you just covered them up earlier!

Liquid Nails, Silicone, & Insulation

Be careful to with silicone and liquid nails against insulation. Depending on the ingredients in the glue, it can actually eat away the insulation and you’ll be left with a huge hole in your insulation! We were able to use liquid nails on insulation just fine, but be sure to test it out before applying.

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