Flooring for Finished Basement
casabian
| Posted in General Questions on
What products do people prefer? I have a space I will be finishing. First flooring guy I met with recommended Coretec but wondering if there are other opinions. I will have foam underneath the slab.
It’s about 1000 square feet. I’d like something that’s waterproof and am leaning towards luxury vinyl.
Thanks!
Ed
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
How about linoleum? Not vinyl called by that name but the real linseed-oil-based product, sold under brand names like "Marmoleum".
We like our Gorilla Raskin Floors. Ours are loose lay and water proof so you could pick them up and put them back when things dry out.
https://www.raskinind.com/
Walta
Walta,
Which ones do you have, I saw a lot of different loose lay options. You can pick them up that easily? Are they more waterproof than other products out there? Thanks
I like tile--ceramic, porcelain, natural stone, or glass. Installation is a bit more work than other materials but if done right they make a durable, water-resistant, very long-lasting floor. DIY-friendly if you're interested.
"Luxury" vinyl planks are all the rage right now. They are durable, easy to install (from what I hear) and look halfway decent. I just don't like plastic floors. ("Luxury" in quotation marks because I have not seen, and can't imagine seeing this in a truly high-end home. Clever marketing, though.)
I've done cork tiles on a few projects--not particularly water-resistant but feel great under your feet and come in a variety of warm colors and patterns.
If Marmoleum isn't available in your area, you can check out this website:
https://www.greenbuildingsupply.com/
I believe they also have cork options.
If you don't mind a plastic look, then most acrylic/vinyl options should be durable and waterproof.
I agree with Michael, when budget allows, tile usually looks better (when installed properly).
With a healthy budget, you could check out this website:
https://www.ecosupplycenter.com/products/
The products look higher-end, and I'm sure it's reflected in the price (maybe with some exceptions).
We went with a painted floor, albeit with a more unorthodox look:
https://kimchiandkraut.net/tag/paint-splatter-floors/
Less expensive than most options, and, so far, holding up well to rough use.
I've done ceramic tile, cork and vinyl. Tile is tough and durable but also hard and cold. The sound reverberates which makes the room noisy.
Cork is the nicest, but it's not as water resistant as the marketing would lead you to believe, it can't survive a soaking the way tile or vinyl can.
I really like vinyl, in particular the LifeProof at Home Depot. It's quite tough -- it wears out saw blades during installation. It's warmer, softer and quieter than tile. Not quite as nice as cork but much tougher.
Just a thought after reading this. Could you lay down plastic dimple mat then put lvl right on top of that. There’s no organic material then, I have been going back and forth with adding a subfloor just wanted to know if this is possible. One person a few years back was trying to convince me to just lay lvl directly on concrete
You don't want dimple mat under vinyl. You want an unyielding substrate, you don't want it to be able to flex. If you have liquid water under your floor you need to fix that with perimeter drains. If the slab doesn't have a vapor barrier the vinyl makes a pretty good vapor barrier.
Yes wondering if I can put the Lifeproof directly on the concrete. Do you think I can lay it myself? Very limited DIY but it seems like it just locks together.
I've put Lifeproof directly over concrete. It has a rubber backing that absorbs minor imperfections in the concrete. If the floor is seriously uneven it will open at the seams. But I'd say it's more forgiving than ceramic tile that way.
So this is where I get confused with all the different options available. What is best for an old basement, low ceilings, and no vapor barrior under concrete when your number 1 concern is mold and ceiling height? These are the options I have seen on here, around internet, and fine home building. Sorry if I’m beating a dead horse but is it just a matter of opinion or what is the current science? Did it change? What if you don’t care about a toasty floor under your feet? If you can just use lvl directly on concrete why not throw down area rugs on top for warmth. Of course a newer house has the built in vapor barrier so that might determine if you can use anything directly on concrete.
-1inch foam 1/2-3/4 inch plywood on top, then whatever flooring
-plastic dimple on concrete 1/2-3/4in plywood on top
-drylok paint on floor, then dimple or foam followed by plywood
-6ml poly, then dimple or foam, then plywood
-lvl directly on concrete
I mean of all these choices I would think lvl is easy to put down and is the only inorganic option, killing the worry of mold, I’m assuming there is a reason for a subfloor though
Joe, depending on a bunch of factors, any of your options except the last one could be safe options. Placing an impervious flooring material directly on a concrete basement floor with no vapor retarder below the concrete will likely result in moisture accumulating under the flooring. Mold won't eat the flooring itself but it will find other stuff to eat, if it has access to moisture and if the temperature is over 40-50°F and less than about 90°F.
I really don't understand dimple mat on the floor. On walls, it is used as a rain barrier, if the wall itself doesn't serve that role, the dimples allow water to flow down the wall without hydrostatic pressure building up.
The way I see it, dimple-mat systems on floors have a relatively small delta T and include a dead air space, so they should insulate about as well as foam would, and in the occasional minor flood they will drain more quickly. I prefer subfloor over foam, with or without sleepers, but if people are pre-sold on dimples I don't try too hard to talk them out of that approach. At least I haven't found a reason to talk them out of dimples.
Why would the flooring itself not serve as a vapor barrier?
That’s why I’m confused. Vinyl, foam, and dimple Matt are all basically made of plastic. Lvl is like a hard piece of plastic, so why include wood into the assembly that is organic. I’m just thinking out loud you guys are the experts that’s why I’m following the advice. I’m just confused on why you need to add organic subfloor if with lvl you can walk directly on plastic.
Joe, if there was a structural subfloor available that was not organic that would work too, but I'm not aware of any.
There are two potential problems you need to address. The first is keeping the condensing surface--the first impermeable surface that relatively warm, moist air in the room "sees" as it tries to get to your cold concrete floor--warm enough to avoid condensation. It doesn't take much insulation to keep the condensing surface warm enough to prevent condensation, but it takes something.
The second issue is that without a vapor barrier under the slab, you will also have whatever moisture is in the ground, which could be a little or a lot, trying to get into the comparatively dry indoors, and it will condense on the first impervious surface it reaches. If there is a completely continuous, impervious layer between this condensation and the indoor air, mold might be able to grow but it would not be able to do any harm. But it's somewhere between hard and impossible to create such a perfect barrier, so instead you have risk of mold growing and impacting the occupants.
Also, you've written "lvl" a couple of times. I believe you mean LVT, luxury vinyl tile or LVP, luxury vinyl plank.
Yes I mean to say LVP. So I’m not advertising anything but dmx makes one step 2.0. They say it’s strong enough that you can put lvp on top without worrying about lvp shifting vertically and that it creates a vapor+air barrier. It can also be put right over concrete with seams taped. I linked the video, I want to know if this is BS, or simply that the underlayment is not thick enough to prevent mold. It’s not organic and probably not structural but thin enough where you still have hard concrete underneath.
https://youtu.be/7hTlFCa0JkM
I don't have experience with that product. His sales pitch mostly makes sense, aside from the common mistake of saying that moisture "condensates." (It condenses, or creates condensate.) I'm not sure that a 1/8" air space is enough to actually allow much drying, and it's only providing a small amount of insulation, though possibly enough to prevent condensation on the flooring surface (depending on slab temperature, room temperature and relative humidity.).
I disagree with his fundamental premise, which is that you want vapor that comes through the slab to dissipate into the room. The whole point of a vapor barrier is that you don't want that, you want to keep the vapor from entering the room in the first place. As long as the vapor barrier is intact, it doesn't matter if there is condensation on the outside of the vapor barrier.
Now, if you didn't have complete faith in your vapor barrier, I could see wanting an air gap between the vapor barrier and a permeable finished floor, so that any vapor that gets past the barrier has an easier path to dissipate. But that's not how this product is used. The installation instruction is to install it with the dimples down and the flush side up. So the layers are slab -- air gap -- vapor barrier -- finished floor, with zero gap between the finished floor and the vapor barrier. And clearly this product is meant to be used as a vapor barrier, it comes with a roll of tape for sealing the seams. The air gap behind the vapor barrier makes no sense.
Dimple mats make sense for rainscreens on walls. I don't see them having a place on floors.
So I’m interested to hear what you think would be the best set up in a low ceiling in an old basement without insulation under slab.
Vinyl plank laid directly on the slab.
I always thought that would work, you are only the second person I heard who would do that. So in that set up what about walls. Foam board against walls, wood wall in front, what would wall sit on concrete or lvp, or something else
Framed wall would sit on a capillary break material.
I have also done LVT directly over old slab with no vapor barrier. It was a dry basement with no moisture issues. Seems to be holding up well.
The one belts+suspenders approach I would do is roll the concrete with one of the decoupling/vapor barrier products (redguard, hydro ban, aquadefense etc). This would keep any moisture inside the concrete and away from the flooring.
I know someone that basically did the same thing but rolled the entire floors and walls with 3 coats of something like that, I wonder how it is holding up.
My family has a rental property with a finished walkout basement, in Maine. Built in 1995 on pure sand, no visible moisture issues but I'm sure there is no vapor barrier or insulation under the slab. Starting 15 years ago we rolled the floor with an epoxy paint. Now every 2-3 years it needs to be repainted, mainly due to moisture, based on where the paint flakes off. We also put down rubber Waterhog mats in a few areas and when we pulled them up there was liquid water accumulation between the mat and the concrete. Again, everything looks dry. We run a dehumidifier and have never seen liquid water or even dampness in areas exposed to air.
If you want to risk it, go for it--there is a decent chance you won't have problems. But I know from first-hand experience, and it's not complicated science, that there is a reasonably high risk of moisture accumulating under impervious flooring. As a designer I have been in dozens of basements with vinyl tiles on the floor and I can't recall one where they weren't loose in some areas. I would not do it in my house, and I would never recommend it for a client, because mold can be a serious health risk.
I would do DriCore (or equivalent), a foam layer, and floating engineered hardwood. That makes it feel like a real, warm room, not a basement. But it depends on your price preferences, ceiling height, and whether it generally stays dry down there.
In most of the US the year-round ground temperature at typical basement depth is in the 50's. The heat loss through a basement floor during winter is pretty minimal, and if you live in a place where you air condition in the summer you get free cooling in the summer. So insulation under the floor isn't critical.
If you live in a place with high humidity in the summer, there is a risk of condensation. The best way to prevent that is to air seal your basement ruthlessly, and either dehumidify or run AC. Often basements don't have enough of a cooling load to get the AC to run much, so you may have to circulate air with the rest of the house if you're relying on AC.
Walls do need insulation, and air sealing, vapor barrier and a rain barrier. Unless you have absolute confidence in your waterproofing I like a sheet of poly from mud sill to floor, ideally directed to a perimeter drain. Then I like rigid foam with the seams taped and furring strips. I don't believe that insulation that can absorb water at all belongs any place below the floor level of the first floor. Between the slab and the insulation I like a treated piece of 2x as thick as the insulation plus furring. Vinyl plank goes against the 2x (with a quarter inch gap for expansion), drywall (mold resistant) is half an inch off of the slab, baseboard covers the gap between floor and drywall. Just to be careful I'd use Azek for the baseboard.
#25 is in response to #23.
Also, let me add that air sealing and insulating the rim joists is a critical part of this. An air-tight basement is a healthy basement.
Thanks this all makes sense, so to make sure I got everything right. 6 mil poly on walls, anything under lvp? Foam board against wall then seams taped. Insulate and air seal rim joist as well. Furring strips then attached to wall. This is where I got confused you said between slab and insulation place a 2x as thick as insulation plus furring strips. Is this on the floor pushed against foam insulation. If there is furring strips why do you need a 2x on slab? Maybe I’m just not understanding this part.
The 2x is between the bottom of the foam insulation and the slab. By "as thick as insulation plus furring strips" I mean if you have 3" of foam and 3/4" furring strips the 2x is ripped to 3-3/4". I probably should have said "as wide as the insulation plus furring strip is thick." That way the furring strips are off of the concrete and toenailed into the 2x. It does mean that the bottom 1-1/2" of the wall is uninsulated, but so is the adjacent floor.
Now I think I understand the set up. The foam sits on the bottom plate, bottom plate thick enough so you can toenail 2x into the bottom plate. Are you still drilling through furring strips and foam to attach furring strips to wall or are you actually using a top plate? Why is this done as opposed to foam from floor to ceiling and then a 2x4 wall pushed up against the foam or furring strips attached through foam and wall? Does this have to do with air sealing or is this to beef up foam insulation without taking up more space.
Right, I left off a detail. At the top of the wall there is also a top plate. It's needed for fireblocking. If the ceiling is drywalled fireblocking has to be continuous from the edge of the mudsill to the drywall. This has the added benefit of making a level surface inside the joist bay from rim joist to the drywall, which you can then insulate with a piece of foam. Depending on your wall the distance from the mudsill may be greater than a 2x4 or 2x6 will span, in which case a piece of plywood can be ripped to fill the gap.
I like a bottom plate because it keeps the foam and furring strips off of the concrete. That way the furring strips don't have to be pressure treated and the foam can be polyiso, which has a higher r-value per inch and thus allows for a thinner assembly. I also like it for the reasons that interior partitions have bottom plates: it's easier to make the wall straight, it gives something to attach the drywall to at the bottom, and it gives something to attach the baseboard to. You want everything about this wall to be air-tight, with a top plate, bottom plate and fireblocking the drywall forms an airtight layer too (in addition to the vapor barrier and the taped seams on the insulation).
The furring strips are attached every 24" with tapcons and toenailed top and bottom. Either 1x or 2x, turned flat.
Lots more conversation here so just catching up. I think I'm following along but would love thoughts on my plan.
Slab will be poured next week. I've been told to do plastic, insulating foam, plastic and then slab. The ceiling is 9'8" and will have AC/Dehumidification. I'm really hoping for this to be comfortable additional living space.
My thoughts are to do LVT on concrete (Lifeproof product) or potentially Coretec flooring (but it's a lot more expensive, and not sure I understand the difference). I'm on Cape Cod so don't think I want tile but open to suggestions.
Love learning on this website, thank you all!
Perimeter drains and exterior dampproofing are really important too. Where you are is a very harsh, very damp climate. Very humid summers, and wicked storms with lots of rain and wind. When it's that humid if any water gets in it will have a hard time drying, you really have to work hard to keep water out.
I did the Tremco water proofing and perimeter drain, so hoping that will do it. Any other tips for flooring or otherwise?
I have a house on Buzzards Bay. Moisture, mold and mildew are a constant concern. The basement has Lifeproof LVT directly over concrete slab. I've been very happy with it.
Vinyl is generally a bad idea over slab because moisture can't get out. Many people who are having trouble identifying a source of mold in their homes which is making them sick eventually find it beneath the vinyl floor. If you're going to do it, at least wait a few years until the concrete dries out.