And now is the time to install a floor in our van conversion! A floor has many other critical functions than just supporting our feet. Indeed, a proper floor installation prevents water infiltration (= rust), provides thermal and noise insulation, and serves as an anchor for the cabinets. In addition, it should be resistant to wear, be able to withstand enough weight, not produce any squeak, and … look good (yep, that counts!). There are many ways to install a floor in a van, but keep reading to learn our take on it!
The information in this article is still relevant. But we are currently building our second van, and you’ll find our latest and greatest work here:
Disclosure: This post contains affiliate links, which means that if you click a product link and buy anything from the merchant (Amazon, eBay, etc.) we will receive a commission fee. The price you pay remains the same, affiliate link or not.
Material: 3 Seasons
Good for occasional sub-freezing temperatures.
| LAYER | ITEM | QUANTITY | LINK |
| 1 & 2 | Minicell Foam | 7 sheets | eBay |
| 3 | Preferred: Baltic Birch Plywood (½”, 4’x8′) | 3 sheets | Cheaper to source locally |
| Alternative: Exterior Plywood (¾”, 4’x8′) | |||
| 4 | Vinyl Floor | 13′ wide x 8′ long | Cheaper to source locally |
| 0/1 | 3M 90 Spray Adhesive | 1 | Amazon |
| 3/4 | Vinyl Floor Adhesive | 1 | Amazon |
| Wood Filler (only if using exterior plywood) | 1 | Amazon | |
| Silicone II (for caulking the vinyl floor periphery, step 7.6) | 1 | Amazon | |
| Great Stuff “Gaps & Cracks” | 1 | Amazon | |
| Vinyl Floor Seam Sealer | 1 | Amazon | |
| Stair Edging (1-1/8″) | 1 | Amazon |
Material: Snow Chasing
1" thick XPS for Full-On Snow Chasing!
| LAYER | ITEM | QUANTITY | LINK |
| 1 | Minicell foam | 3 sheets | eBay |
| 2 | XPS foam (1″ thick, 4’x8′) | 3 sheets | Cheaper to buy locally (product example: Insulation4us) |
| 3 | Preferred: Baltic Birch Plywood (½”, 4’x8′) | 3 sheets | Cheaper to source locally |
| Alternative: Exterior Plywood (¾”, 4’x8′) | |||
| 4 | Vinyl floor | 13′ wide x 8′ long | Cheaper to source locally |
| 0/1 | 3M 90 Spray Adhesive | 1 | Amazon |
| 1/2 | Silicone II | 3 | Amazon |
| 2/3 | PL300 Foam Board Adhesive | 2 | Amazon |
| 3/4 | Vinyl Floor Adhesive | 1 | Amazon |
| Wood Filler (only if using exterior plywood) | 1 | Amazon | |
| Great Stuff “Gaps & Cracks” | 1 | Amazon | |
| Vinyl Floor Seam Sealer | 1 | Amazon | |
| Stair Edging (1-1/8″) | 1 | Amazon |
NOTES:
- Minicell thickness: Transit = 0.40″, Sprinter & ProMaster = 0.30″. Choose thickness in eBay store.
- Quantities shown are for our van (Transit extended-length) and may vary according to your van model. For Minicell quantities, follow recommendations in product description (eBay store).
- We used ½” XPS (in pink) to fill the corrugations, but we would use Minicell if we had to start over. Read our “Second Thoughts” at the bottom of this page for more info!
Tools
| Item | Description | Quantity | Link |
| Snap-Off Utility Knife | Stanley 18mm. | 1 | Amazon |
| Caulking Gun | For 10 oz cartridge. | 1 | Amazon |
| Jig Saw | DEWALT Cordless Lithium-ion 20V. | 1 | Amazon |
| Blade Set for Jig Saw | 14 Pieces. | 1 | Amazon |
| Circular Saw | DEWALT Cordless Lithium-ion 20V, 7¼ with brake. | 1 | Amazon |
| Circular Saw Blade | DEWALT Precision Finish Blade 60 tooth. | 1 | Amazon |
| Trowel | 1/16″ x 1/16″ x 1/16″ Square Notch. | 1 | Amazon |
| Rolling Pin | To roll tasty vinyl pies. | 1 | Amazon |
| Painters Tape | To protect the van walls when working with Great Stuff Foam. | 1 | Amazon |
Good To Know
Floor Layers In A Nutshell
Layer 1: To Fill corrugations
- Provides thermal insulation (and sound insulation to a certain extent).
Layer 2: Top of corrugations
- Provides thermal insulation (and sound insulation to a certain extent).
Layer 3: Underlayment
- Provides a smooth and level surface for good adhesion of the finish layer.
- Supports and distributes weight.
- Serves as an anchor for cabinets.
Layer 4: Finish
- Looking good!
- Protects against liquid infiltration (and therefore, rust). Trust us, spills WILL happen! That’s why we went for large vinyl sheets (2), instead of multiple vinyl tiles (to minimize seams).
- Shall be wear resistant.
Choosing A Plywood
Baltic Birch
The plywood underlayment shall be moisture resistant, exempt of any warp, and the surface common with vinyl flooring shall be nice and smooth. That’s why we prefer Baltic Birch. It is laminated with exterior grade adhesive, it’s straight, the surfaces are smooth (no wood filler needed) and it’s very dense (screws grip better in it). As a result, ½” should work well. Note that we wouldn’t treat the entire plywood sheet: just the edges. Indeed, it is sandwiched between the vinyl floor and the foam (XPS or Minicell), so it’s not exposed to high level of moisture or condensation.
Exterior Plywood
Exterior plywood commonly found in hardware stores is glued using exterior grade adhesive and some of it is also treated for protection against fungal decay, rot, and termites. Compared to Baltic birch, it is made of thicker plies, so fewer plies are needed to obtain the same thickness. Therefore, the resulting plywood is less dense and warps more easily. We’ll go ahead and say that even if the underlayment is exposed to some moisture, it’s not a requirement to use treated plywood because it is “protected” by the vinyl floor and the foam (XPS or Minicell). If using plywood to fill the corrugations, that’s another story…
Choosing the XPS foam
You’ll find XPS branded as “Foamular” 150, 200, and 250. This number is relative to its compressive strength. 150 is capable of supporting 15 PSI, 200 can support 20 PSI and 250 is capable of 25 PSI. Knowing that a human footprint is equal to approximately 16 PSI, it’s a good idea to choose XPS higher than 150 (15 PSI). Note that the plywood underlayment will take care of distributing the weight to a larger surface, so any foam should be OK. That being said, there’s a pretty good chance you walk on the foam during the van build (before installing the underlayment); you’ll appreciate if the foam doesn’t collapse under you 🙂
Attaching The Floor
Believe it or not, there’s no need to secure anything; the floor isn’t going anywhere! The large plywood sheets, combined with the weight of the cabinets (and others) will ensure the floor stays where it belongs. Doubt it? We completed our conversion in 2017 and our floor hasn’t moved at all. And many people have used this technique with the same results.
So, why are we recommending to use adhesive anyway? The adhesive doesn’t provide any kind of “structural” bond: its role is to keep everything where it belongs during the floor assembly & to prevent squeaks, especially with XPS. We repeat, XPS squeaks if not attached properly! Keep reading for recommended adhesives.
All of that being said, we see a scenario where we would attach the floor to the van: if no cabinets are added to the van and a slide-out-bike-rack is installed. Then, it might be a good idea to attach it (because of the long lever when the bike rack is out).
Adhesive Compatibility
| Minicell | XPS | Metal | Wood | |
| 3M 90 | Yes | NO! | Yes | Yes |
| 3M 78 | Yes | Yes | Yes | Yes |
| 3M 77 | Yes | Maybe | Yes | Yes |
| Great Stuff (Gaps & Cracks) | Yes | Yes | Yes | Yes |
| Silicone II | Yes | Yes | Yes | Yes |
| PL 300 | No | Yes | Weak | Yes |
Choosing the right adhesive
Like it or not, there’s no perfect “universal” adhesive (because CHEMISTRY). The “best” adhesive depends on materials, application context, use context, availability, and cost. Based on the previous table, here are some options:
- 3M 90: This is the stuff we used to glue Thinsulate to the walls and ceiling. Works great, except it WILL attack XPS. Bond time = 15 minutes.
- 3M 78: Designed specifically for foam, it’s probably the best option (technically speaking). However, it’s costly and more difficult to find. Bond time = 30 minutes (it means you have 30 minutes to put everything together and apply pressure).
- 3M 77: It used to be safe for XPS (polystyrene), but 3M had to change the ingredients recently. We’d recommend testing it before using it with XPS. Bond time = 15 to 30 minutes.
- Great Stuff Gaps & Cracks: Not technically an adhesive, but people use it successfully to glue foam. It’s very cheap and easy to find, but it can be messy if not careful. Bond time = less than 10 minutes? (test it, not sure exactly).
- Silicone II (not acrylic): Not technically an adhesive, but it works great for the current application (prevent squeaks). Quite cheap and easy to find. Bond time approximately 15 minutes.
- PL 300: That’s what we recommend for bonding XPS to wood. Won’t work on metal or with Minicell. Bond time = 20 minutes.
Joining the plywood (to get an even seam)
Some people are getting uneven seams where the plywood joins together. We personally didn’t get this issue, but we would highly recommend looking into joining techniques to increase your chances of success, such as:
Lap Joint
Biscuit Joint
Some don'ts
Framing
We often see people framing their floor, the justification being that it “stabilizes” the floor. Unless you are using compressible insulation (Thinsulate, wool), there’s just no need to do this. The van’s floor is stable enough. Good reasons not to do it: 1- frames are thick and vertical space in a van is precious. 2- Wood is a good heat conductor, so the frames create thermal bridges (in other words, it’s bad for insulation. Check out our “Insulation Guide” for more.).
Metal screws
Each screw added to the metal of your van is a potential ignition point for rust. Knowing that the floor is a very sensitive zone for rust, we really recommend not screwing liberally through it. There can be some exceptions to this (we personally drilled a few holes for the Webasto & Propex heaters, composting toilet exhaust, grey water drain, propane locker vent and floor vent), but the bare metal of each added hole/cutout should be primed + painted to prevent corrosion.
Saving Time and Hassle
We recently stumbled on the Bedrug Cargo Mat. It’s a 1/2″ thick closed cell foam mat (polypropylene = resistant to chemicals & weight) that is custom-made for various vans (Transit, Sprinter, ProMaster, etc.) & wheelbases (short, long, extended). The mat fills the corrugations (neat!), the custom fit means there is no trimming involved (which can literally saves you HOURS!), and as a bonus the mat can be used as a floor template (for the plywood or else). We think it would make a great alternative for the minicell insulation in the “3 seasons” floor layout (layers 1 & 2), or it could be used as a standalone floor for simpler builds.
(choose your van & model from the search result)
And now let's get to work!
1- Clean Everything:
Cleaning is NO FUN.
2- Fill the corrugations with the Minicell (Floor Layer 1):
NOTE: We used ½" XPS for this step (as shown in the pictures), which is too thick, so we would use Minicell if we had to start over.
2.1- Cut the XPS (Minicell) using the utility knife.
2.2- Install on the van floor using adhesive (3M 90 adhesive with Minicell).
The XPS Shake:
Put some of the leftover C-200 XPS strips in the blender with vanilla, protein powder, ice cubes, and decorate with mint. Enjoy!
3- Install the XPS or Minicell (Floor Layer 2):
3 Seasons = 0.25" thick Minicell.
4 Seasons = 1" thick XPS.
3.1- Isabelle crafted a template from some random brown left overs. It helped making clean cuts on the insulation.
2.2- Add the XPS or Minicell and secure in place using the adequate adhesive (XPS = Silicone II, Minicell = NONE).
We left a gap of about ½” all around the van wall to account for installation variations and to ensure there would be no squeaking noise. This gap will be filled later with Great Stuff.
4- Install the plywood underlayment (Floor Layer 3):
TIP: Use the foam (from layer 2) as a template, it'll save you some time! And don't forget to take your shirt off when using a circular saw.
Isabelle approves the result and the shirtless display.
Secure the plywood to the XPS using PL300 (remember, this is to prevent squeaks) and apply weight. If using Minicell, no adhesive is required (Minicell doesn't squeak).
Cannot find any weight? Leaving a bowl of food on top of the surface to be glued will inevitably attract heavy weight.
6- Before adding the finish layer...
Cavities on the plywood were filled with wood filler and then sanded flush. If using baltic birch, this step is not required as it is already smooth.
To seal the gap and make a nice & flat surface for the vinyl floor, we overfilled the gap with Great Stuff (Gap & Cracks), let it dry, and then trimmed it flush with the plywood sheet (using a utility knife).
7- Install the vinyl sheet (Floor Layer 4):
7.1- We bought a sheet of 8'x13' vinyl and trimmed it as follows:
The goal is to have the "planks" oriented lengthwise and to have the seam "hidden" under the bed:
7.2- Something like this:
TIP: We were told not to trim the vinyl to its final dimensions right from the start, and that was a GOOD TIP! Work with extra length, and do the final trim AFTER it's glued. Indeed, it’s almost impossible for the vinyl to return to the same exact location after the glue is applied (because it will slightly move and stretch). That's why we initially trimmed the vinyl to 6.5', which is slightly larger than its final dimension (~6').
7.3- Follow the instructions on the vinyl floor adhesive: use the appropriate trowel and the right amount of adhesive (not more).
7.4- The vinyl was stretched and bubbles removed using a rolling pin. Notice the extra material around the periphery: that will be trimmed to its final dimensions later.
7.5- Then we proceeded with the second vinyl sheet. To make a nice seam between the two sheets, we slightly overlapped them and trimmed both sheets (simultaneously) so they have the same exact trim. No picture of the seam, sorry 🙁
7.6- We caulked the vinyl floor periphery with GE Silicone II. Unlike acrylic, Silicone is permanent: it doesn't dry and doesn't crack, it's very flexible and it remains elastic from -55F to 400F.
8- Install stair edging:
As a final touch, we added an aluminum stair edging at the sliding door, passenger/driver seats, and at the back of the van (garage).
Because the stair edging is only 1-1/8″ and our floor is thicker (we went for the "snow chasing" mode!), we added a wood trim that we painted grey to match the van's magnetic grey. The wood trim is screwed into the plywood layer of the floor (the screws are hidden by the aluminum edging).
9- OMG WE HAVE A FLOOR!
On Second Thought...
Things we would do differently
- We initially went for ½” XPS to fill the corrugations and we would now go for Minicell (because it has exactly the right thickness).
- We initially installed a layer of MLV (mass loaded vinyl) for soundproofing, but we feel it was superfluous. This thing is HEAVY and sandwiching it among the floor layers is not how it’s meant to be installed to be effective. So save yourself the trouble!
- We used exterior plywood and left it in the sun for some time… It warped the plywood big time. Next time we’ll use Baltic birch and keep it away from the sun!
- This page was updated to reflect how we would do things next time!
How cold is the floor in winter?
Heat rises, right? So we expected our floor to be constantly cold. Turns out the Webasto placement is perfect as it blows hot air parallel to the floor. As a result, our floor is nice and warm even when it’s way below freezing temperatures outside. Neat!
That being said, it might not be the case for different layouts… If your “living area” is in the back and your Webasto in the front, the floor might be cold in your living area.
Any change over time?
Nope! The floor is still level and doesn’t squeak 🙂
Wondering when you said you would have done both layers of floor insulation (corrugations & layer 2) in mini cell, what density of foam were you planning on using? I see it come in 2, 3, 4, and 6 lbs densities. Having never seen it in person I’m wondering if it would be necessary to get one of the higher densities to prevent compression or a “spongy” feeling to the floor?
There is a link for the Minicell under “Material” section of this page (eBay). It is 2 lbs density.
cheers!
Hello,
Just wanted to start off by saying this is such a great guide! It has been extremely helpful for my build so far.
At my local hardware store, I found birch plywood, but am unable to find “Baltic” birch plywood. Is there a difference between Baltic birch and regular birch? If so, is 1/2” regular birch plywood sufficient for the flooring or would recommend using something else? I am doing the Snow Chasing floor model.
Thanks in advance!
Ethan
Baltic birch plywood has about twice the number of plys as birch plywood; it is therefore more dense (better grip for screws) and more flat. I’d go for 3/4″ with “regular” birch I think.
cheers
Makes sense. Thanks for the quick response!
Great guide! I’m thinking of using laminate flooring on top of the xps board on the floor instead of plywood & vinyl. Actually for the entire floor, sides and ceiling (on top of the thinsulate instead of plywood), is this a bad idea?
bonjour! D’abord félicitation pour votre site !
Petite question, pour votre vinyle, avez-vous pris en fiberglass ou felt ?
Merci !
Bonne question, aucune idée désolé!
How did you attach the aluminum edging? Thx!
It’s screwed into the plywood (& through the vinyl).
Hello. Love your site. You seem a lot like me. Very detailed! I’m ready to insulate my promaster and live MN so want to stay as warm as possible. My question is around whether we should be putting ANY insulation in the low spots on the floor. My concern is that it may be good to have some air flow there to let things dry out when they get wet. Thoughts?
Thanks.
Hi. Thanks for all the great information.
Regarding Minicell.
Would you add the optional thin layer of 3M TAI?
Antoine,
Thanks for all the expertise and knowledge sharing. I’ve just started a conversion on a new ‘19 3500 144wb sprinter. Sorry if you’ve answered this question prior, but how did you secure the subfloor (plywood) into the van floor? Off topic, but I’m also wondering what you did with the factory wiring loom running interior cargo lights and rear of the van other than remove the protective plastic covers.
I’ve had a great time this far into the project. Learning lots about how vehicles are built. Your blog and posts are priceless and I (like others before me) really appreciate your sharing the lessons learned and experience.
Hey Clayton,
I followed Antoines floor plan in my 2020 Sprinter which is going well, but I also wanted to secure the plywood floor to the van, especially since I extended the floor out into the slider opening a bit. My general plan is To NOT make holes my nice new van if possible, so I uncovered the existing threaded holes That the factory floor and tie downs used (8mm metric threads) which I used to bolt down the ply with countersunk flat-head machine screws.
There are no threaded holes in the middle section of the floor, and I wound up with 3 pieces of subfloor (seams running across the vans corrugations) To keep the middle piece down I routed a 3/4” Lap joint at each seam, Front and back lapping OVER middle piece, so the front and back bolted down sections hold the middle in place.
A bit of work really, and not that I plan on it, but I can unbolt that floor and return the van to new if necessary.
The floating floor sounds fine but I enjoy the solid feeling Of tied into those original holes.
Good luck, Henry
A question about using the silicone ii between the xps and the minicell. Did you just apply it to the xps?, or did you apply it to metal and minicell?
Does it make any difference?
Thanks
I’ve been searching for the same answer. In a previous comment one page over, Antoine replied to a similar question, “The silicone II is between the XPS and the metal (to minimize squeaks); it’s not necessary to have adhesive between the minicell and the XPS.” Hope that helps!
Just a PSA that 3M 77 DOES NOT work well for foam board to metal. Figured it couldn’t be much different to 78, but boy were we wrong! Definitely go w 3m 78 for XPS
Great site! Hope it’s workin out for y’all! I’m planning a build on a 2020 Transit (144” STD box, Med roof).
Would you recommend using sound deadening peel&stick material (rattletrap) under the Minicell foam, or is that redundant?
I don’t think that’s necessary! I’d skip it.
antoine
This guide is great. Its probably worth noting that there is 1/4″ XPS foam available as well. That is what we did and it was fairly simple. It is thin enough to be super easy to cut.
Where did you find 1/4 XPS? I can’t find anything thinner than 1″ at my local stores.
Howdy Antoine and Isabelle.
I just got a 2020 Transit and am about to start building it out. I have gone through your site multiple times to get ready for this. I do have a question. I know you said that you would use Minicell instead of the XPS, was that strictly for layer 1 or for both layer 1 and layer 2?
Thanks for all the work you have done and will save me. 🙂
Best Regards,
Loren
Layer 1 only. Actually we would do it exactly as shown under “Material” section (3 or 4 seasons).
antoine
Thanks Antoine.
First off I love your site. I’ve been researching a built for about a year. It seems like every Q&A out there comes back to the two of you in three clicks. (7 degrees of Kevin Bacon).
I have purchased an ‘18 2500 Promaster and have started purchasing the larger $ items. I was wondering if there are any major upgrades to the Electrcal system that you would suggest.
Probably so that the “planks” run the long way through the van
I was wondering the same thing but the smaller piece wouldn’t be wide enough if they turned it to orient the planks lengthwise. Anyone have more info on this question?
Oh gosh we made a mistake in the original sketch, we just updated it. This should make more sense now!
I a little confused on the seem in the vinyl. Why is 2 pieces if you bought it as 13 feet long?
I’m having the same question
Did you ever get an answer? I feel like I’m missing something regarding the need to cut into 2 pieces! What did you end up doing?
Oh gosh we made a mistake in the original sketch, we just updated it. This should make more sense now!
Oh gosh we made a mistake in the original sketch, we just updated it. This should make more sense now!
Hello! I’ve been going back and forth about insulating my Ford Transit Connect Cargo van. My question is: if I insulate only certain areas of the walls (like in cavities), is that ineffective? And therefore not worth insulating at all? Will the areas not covered by insulation (like where the wheels stick out) defeat the purpose of insulating at all? Thanks so much!!!
Just finished installing the 3 season floor. I think I put in about 14 hours. Maybe I measured incorrectly but I believe the measurements for the vinyl floor may have been a bit shy. I would suggest making the vinyl 15 feet long instead of 13 to allow for some wiggle room. I was also thinking it would be a good idea to caulk around the bottom of all the stair edging just to make sure no moisture gets under the floor.
I ended up using 4 sheets instead of 3 so I would have less seams.
I also ended up using 2 bottles of caulk.
What do you think about minicell .30 for corrugations, layer 2 minicell 3/4 inch, layer 3 1/2 inch wood, layer 4 vinyl?
We were thinking the same thing! Did you end up doing it that way? How did yours turn out?
Isabelle and Antoine, I love what you do, your energy, spirit and lust for adventure! Your website and sharing all your experience is supersuper helpful! I want do similar minimalist conversion and the amount of information out there is overwhelming, you guys are golden, your simple and visual guides save me tons of time! Now I actually think its doable, haha. I also love your choice of organic healthy materials for insulation. This is absolutely fantastic!
Thanks for your awesomeness and keep rocking! May be will meet you one day on the road
Have a safe journey
Greetings from San Francisco