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 🙂
Hi antoine,
Getting back into my project after a busy work season. I am installing the floor,just minicell. I am looking at the stair edging and have 2 questions..one it say it is attached with screws..oh no we dont want holes..and how did you do the edging in the “garage” as we don’t want to cover the spare tire access.
Thanks,
Barbara Enjoy Mexico by the way..check out Barra de Navidad on the west coast..
The stair edging is screwed into the plywood, not into the van’s metal floor 🙂
In the garage, the floor stops before the bolt for the spare tire…
Good luck 🙂
Antoine
Thanks for this! Just followed your guide for the floor in my 95 Econoline Conversion van.
I used 3M 77 on the XPS and it worked fine. When I tested the 77 on the XPS the adhesive slightly deformed about a mm of the XPS but that was it. Versus my other tests of 3M 90 and Gorilla Glue foam adhesive spray which ate through the foam like pouring hot water on ice ha.
Now that my floor is in, I have one concern – MOLD. My van will be used heavily as a beach vehicle. Are the XPS and birch water resistant enough? Should I have mold treated the birch? Hindsight is 20-20….
Just make sure that your top layer is “waterproof”. In our van, that’s the role of the vinyl sheet; water can’t get through.
I’d be more worried about mold in a “ski” vehicle than in a beach vehicle, because of condensation…
Cheers!
Hi Antoine,
I am converting a Transit Van right now and currently working on the flooring. I noticed you didn’t take the flooring out to the edge on the rear doors. Is there a reason you stopped it short? Love your website.
Stu
It’s to retain access to the spare tire; there is a bolt that is used to lower the tire under the van…
🙂
So I have been going all around my area trying to find 1/2 inch XPS board. I can not find it anywhere. Where were you able to buy it?
By the great site it has helped me alot in my build.
We bought it from Home Depot in Canada, but when traveling I noticed hardware stores in the USA don’t carry much XPS; don’t know why.
https://www.homedepot.com/b/Building-Materials-Insulation-Foam-Board-Insulation/XPS/N-5yc1vZbaxxZ3q5Z1z0w1xo?experienceName=default
Hey there Isabelle and Antoine. Your website has been so inspiring as well as helpful, thank you for sharing so much of your experience! Ive been looking everywhere for Foamular XPS 250 – 1″ thick and cant find it. I only find the 150 in 1″ thickness, the 250 in 2″ thickness. Do you see any problem with using the 2″ thick Foamular 250 in the flooring insulation? All the other layers would remain the same with the Minicell foam being Layer 1. Best wishes and Viva la Mexico!!!
2″ is quite thick… I think I’d go for the Foamular 150 and take care not to walk on it during installation. Once you’ve got your plywood installed, then the 150 should be just fine.
Good luck!
I may have missed this question previously… but what do you mean you overlapped two sheets of vinyl? We are following your instructions pretty religiously but I am not so sure what that meant! Did you overlap and then cut one side? Thanks so much!
Where you want your joint: make the sheets a bit longer (so they overlap about 1″), then cut both of them simultaneously using an utility knife. The resulting cut should be perfect.
Hope that makse sense!
Hello!
I was wondering what you did to seal up the floor at the rear doors to stop water from finding its way under the floor? I have my floor installed, and right now it looks like yours in step 9, but I’m not sure what to do to finish it up… Any tips
I read that you used stair edging & trim to finish the the side door, did you use anything else to seal that up in the rear?
Same question!
We also installed a stair edging near the rear doors, same thing!
antoine
Hey,
Love all of this!!! Thank you so much for sharing with us. One question, do you find that you need or want sound insulation in your floor? I’m wondering if its something that you’d do next build?
We wouldn’t bother. The insulation layers as described here are sufficient.
Great information. Thank you. Vinyl flooring makes very good sense to avoid moisture/water getting to the subfloor. Question: What was the reasoning to trim the 13′ length into two sections of 5′ and 8′?
I’m helping a friend build out a pro master van and we’re trying to figure out the floor insulation options. It seems like the corrugations on the floor are much smaller in her van than in your Ford, and as such they don’t make XPS that will fit. Do you think we’d be fine to use a bunch of great stuff foam in the corrugations with 1” XPS and 1/2” bb plywood on top? Or is the $180~ worth of Minicell really that worth it?
She also has the composite floor from the factory. We haven’t seen anyone keep that in place and just build the insulation and subfloor on top of the factory floor, but other than weight, it seems like it shouldn’t be that big of a deal to keep it. Also seems like keeping the factory floor would simplify the insulation install. Thoughts?
Filling the corrugations with Great Stuff will make a mess and be a lot of work; test it first, that might answer your question!
For the other layers (factory floor and all), really it depends on what you want/like.
Good luck!
Hi Antoine,
I read your earlier post about the flooring (before recent edit) and purchased two sheets of Minicell for the corrugations in my Ram Promaster 136″. My plan was Minicell > 1/2″ XPS > Plywood. This will be for the most part a 3 season van. After reading your recent edit, I’m wondering if I should just go with all Minicell for floor insulation. Are the minicell sheets similar in r-value to 1/2″ XPS? THANK YOU!!
The Minicell has lower R-Value than 1/2 XPS. The reason for going Minicell only is mostly for simplicity. If you don’t mind the extra steps, 1/2″ XPS would provide more insulation.
Hope that helps, good luck 🙂
I cannot find Baltic birch plywood with my local suppliers, is the Russian merissier tree also correct? I live in Sherbrooke Quebec.
Merisier russe en français 😉 Langevin Forest en a pour pas cher à Montréal.
Couple of notes
Gorilla glue doesnt hold filler strips.
And
My floor is not even because of it. I needed to use more weight and the correct 3m adhesive.
The one you linked is contained in a sausage pack instead of a caulking tube.
Either way I found finished ply wood to be super nice in terms of it being install ready. I also cut the larger foamboard with the wood to get a perfect match.
Was your floor perfectly even? When finished/before you applied vinyl?
It was pretty much even, yeah. We can noticed a tiny “step” at the plywood joint, but no big deal. The weight of your cabinets and stuff should help too.
Good luck!
Hello
I have a question regarding your Minicell suggestion: I found the material online in either 1/2” or 3/8” thickness which translates to 9.5mm and 12.7mm. I measured the depth of the corrugations of my Ford Transit and it is 11mm. So none of them is the perfect fit. Would you still recommend the Minicell that is slightly too thin? I guess the XPS layer would then only stick to the Van metal but not the Minicell.
Thanks
Peter
Antoine — curious how your floor is holding up with only adhesive holding it down (i.e., no screws). Is everything still tight and flat?
Still holding well and flat! It hasn’t moved one bit 🙂
Hi Antoine,
Sorry to be an “idiot” but I am confused. Are you suggesting minicell for ridges and as an upper layer to replace XPS Foam Board? Also, if using minicell, use same adhesive? And ,lastly, do you use double sided tape between layer of plywood and foam board(or minicell) or another adhesive.
Thanks for being patient with me! But I really want to get this done and hit the road next spring!
Barbara
For summer use: Minicell to fill the corrugations AND as an upper layer (no XPS).
For winter use: Minicell to fill the corrugations, XPS as an upper layer.
Adhesive between metal (van’s floor) & minicell: 3M 90.
*Adhesive between minicell layers: 3M 90.
*Adhesive between plywood and Minicell: 3M 90.
Adhesive between plywood and XPS: PL300 (to prevent squeaks).
If most of your floor will be covered with cabinets (etc), it is acceptable NOT-TO use adhesive where mark with an asterisk (*) above. The weight of your cabinets is what’s keeping the floor in place.
Good luck,
antoine
My floor will follow your suggestion for winter use.
Minicell==> XPS==> Plywood==> flooring, such as Pergo.
Regarding “*Adhesive between plywood and Minicell: 3M 90.”,
I ask: what was used between the plywood and XPS? Was it 3M 90 or PL300?
PL300; that stuff is made exactly for this purpose 🙂
Hi Antoine.,
If using the minicell insulation, do you still recommend the 3M adhesive? Also, how much did you use(obviously different product) because they sell as two part item , corrugated layer and ?top layer?. also, I am considering marine grade plywood, should be less chance of warping.
If you only want to fill the corrugations with the Minicell, you need a little less. If you want to use it as a top layer as well, you’ll need a little more. The quantity are explained in the Product Description in the eBay store.
Hi,
Getting ready to build out a 148″ transit and your site is incredibly helpful. Thank you.
I’m wondering if there was a particular reason you didn’t use the PL 300 to attach the 1/2″XPS to the van?
Thanks!
PL 300 doesn’t bond too well to metal (per spec sheet). It’s been a while, but I believe that’s why!
🙂
Hi guys, looking forward to installing my floor! Thanks for all the posts, they’ve been invaluable so far. As far as installing the floor without the MLV (as you suggest in the “On second thought…” section), what would you use to secure the plywood subfloor to the foam board in that case? Still double sided tape? Thanks!
I answered my own question, the double sided tape is working great for that! Also, using vinyl plank for my floor and so also putting the tape around the edges to keep it from shifting side to side. Still left the expansion gap around the edges and will fill it with Silicone II, but that vinyl tape really does the trick, it’s a lot more bond-y than I was expecting.
PSA for US based followers the XPS boards seem to only come in C-150 and C-250, at least through Home Depot. Home Depot Canada however carries C-200 and C-300.
Any thoughts on using the C-150? 15PSI close enough to the human average of 16PSI? Probably.
Huh, interesting. I’m sure the C-150 will be fine after the installation (the plywood will re-distribute your footprint to a larger surface); just don’t walk directly on the foam during the installation 🙂
Have a good one!