insulating flooring for a home with concrete slab foundation
April 17, 2021 1:42 PM Subscribe
My house sits on a concrete slab embedded in a bedrock ridge, and has an open floor plan on ground floor (which is approx 1350 sq'.) It is soooo cooold for much of the year, even with 6 mini-splits (2 of them on ground floor), one wood stove and a fireplace, 18 solar panels and a Tesla battery. Also heated rug pads which are too inefficient/costly to use often. Current floor covering is aging bamboo laminate.
I looked into thermal flooriing (electrical), but most of the heat would just drain into the concrete, so not at all cost-efficient. I may want to convert my fireplace (opposite end of the house from the existing wood stove) to a second wood stove. But in a perfect world, I could cover the entire floor with rugs (preferably not permanently installed carpeting) that could be removed in the warm weather, when the cooling effect is welcome.
Where might I find custom-cut rugs that are about 1 cm (.4" thick), stitch rate 1/10, density maybe 200-300? Is this just a pipe dream?
I looked into thermal flooriing (electrical), but most of the heat would just drain into the concrete, so not at all cost-efficient. I may want to convert my fireplace (opposite end of the house from the existing wood stove) to a second wood stove. But in a perfect world, I could cover the entire floor with rugs (preferably not permanently installed carpeting) that could be removed in the warm weather, when the cooling effect is welcome.
Where might I find custom-cut rugs that are about 1 cm (.4" thick), stitch rate 1/10, density maybe 200-300? Is this just a pipe dream?
Is it feasible to "raise the floor" by adding another layer?
Basically, you need a layer of insulation against the concrete, THEN maybe heating, THEN your regular floor.
Maintaining the heating would be the most difficult as your floor would probably have to be "modular" so it can be pulled up in pieces to fix the insulation below. So you can remove it for summer and add it back in for winter.
posted by kschang at 2:27 PM on April 17, 2021 [3 favorites]
Basically, you need a layer of insulation against the concrete, THEN maybe heating, THEN your regular floor.
Maintaining the heating would be the most difficult as your floor would probably have to be "modular" so it can be pulled up in pieces to fix the insulation below. So you can remove it for summer and add it back in for winter.
posted by kschang at 2:27 PM on April 17, 2021 [3 favorites]
Would DriCore be an acceptable option? It is widely used in basements, and provides a break (air gap) between the concrete and whatever flooring you want. I think there is also an insulated version with a middle foam layer. It is very easy to install, comes in 2x2 panels
posted by walkinginsunshine at 2:46 PM on April 17, 2021 [2 favorites]
posted by walkinginsunshine at 2:46 PM on April 17, 2021 [2 favorites]
these "baby mats" are quite cute and there's other nice foam interlocking tiles out there!
or carpet tiles are a thing (those ones are fairly fancy, there's cheaper options)
posted by euphoria066 at 3:29 PM on April 17, 2021
or carpet tiles are a thing (those ones are fairly fancy, there's cheaper options)
posted by euphoria066 at 3:29 PM on April 17, 2021
Insulate the floor, top with wool rugs. Wool rugs are not in vogue; if you are persistent, you'll find lovely ones on Craigslist/ FB Mktplace.
posted by theora55 at 3:50 PM on April 17, 2021
posted by theora55 at 3:50 PM on April 17, 2021
Response by poster: All excellent, helpful answers! Thanks!!
posted by mmiddle at 5:35 PM on April 17, 2021
posted by mmiddle at 5:35 PM on April 17, 2021
Do you have an underlayment layer under your current flooring? It usually doesn't require much to create a thermal break.
underlayment
If you do and it's still that cold, what is your average low temperature we are talking about?
posted by The_Vegetables at 12:00 AM on April 18, 2021 [1 favorite]
underlayment
If you do and it's still that cold, what is your average low temperature we are talking about?
posted by The_Vegetables at 12:00 AM on April 18, 2021 [1 favorite]
Response by poster: @The_Vegetables: thanks for that link. I think that’s what DriCore, suggested above, is - underlayment? And then you put laminate or whatever over it. Right now it is just laminate on concrete. (I have to admit, “cold” for me is interior temps in the 50s (this is in western Va mountains) - not that big a deal to some people.)
posted by mmiddle at 3:54 AM on April 18, 2021 [1 favorite]
posted by mmiddle at 3:54 AM on April 18, 2021 [1 favorite]
Yes, all wood floors should be installed with underlayment to prevent moisture issues - if yours were installed directly over concrete with nothing separating the two - you are lucky that your floor hasn't failed. The 'sitting on bedrock' instead of soil probably has helped with that.
posted by The_Vegetables at 4:08 AM on April 18, 2021 [1 favorite]
posted by The_Vegetables at 4:08 AM on April 18, 2021 [1 favorite]
I have a kind of similar house here in the TN mountains except the house is also earth sheltered in the hillside. I wonder if your house is cold specifically on the floor, or throughout? I can have floors that are uncomfortable barefoot in winter, at probably around 55, but the air in the house can be a balmy 65 from purely passive solar heating, and it's easy to push it up to 70 or 75 with a single wood stove. So I just put down a wool area rug in the bedroom and am fine with tiles in the rest of the house -- especially since they're still 60 all summer long. If your house seems so much colder I wonder if it's due to lacking insulation generally, not only on the floor.
(I do not know if my house's slab is thermally insulated; the walls are so maybe but the temperature suggests not.)
posted by joeyh at 8:03 AM on April 18, 2021
(I do not know if my house's slab is thermally insulated; the walls are so maybe but the temperature suggests not.)
posted by joeyh at 8:03 AM on April 18, 2021
Radiant flooring (where there are pipes that circulate warm liquid in the floor) is amazing. Our radiant pipes are embedded in concrete. Maybe you could do some underlayment and then radiant flooring?
posted by leahwrenn at 9:04 AM on April 18, 2021
posted by leahwrenn at 9:04 AM on April 18, 2021
Rugs will help the floor feel less cold on your feet. Frankly, any kind of fabric-y floor covering will - including carpet tiles. But thicker coverings may make more of a difference or at least feel like they will. If you have the budget to replace the bamboo, then wood with good underlayment will be an improvement, but carpeting the place would make a bigger difference (although the aesthetics would be unfashionable).
Hydronic under floor heating would heat up your slab so that it functioned as a giant heat source, and would probably make a difference, but it would raise the floor levels by maybe half and inch or more, which would affect all your doors, your kitchen, your baseboards, everything. So if you were ripping everything out anyway...
Another thing to consider is whether you are using your windows to capture the passive solar heating possibilities of your slab effectively. So making sure that south facing windows are uncovered in daylight, east facing ones in the morning, west facing in winter afternoons while covering north facing ones year round and closing them all at light. Using thick curtains to trap the heat when it's dark is helpful.
posted by plonkee at 7:38 AM on April 19, 2021
Hydronic under floor heating would heat up your slab so that it functioned as a giant heat source, and would probably make a difference, but it would raise the floor levels by maybe half and inch or more, which would affect all your doors, your kitchen, your baseboards, everything. So if you were ripping everything out anyway...
Another thing to consider is whether you are using your windows to capture the passive solar heating possibilities of your slab effectively. So making sure that south facing windows are uncovered in daylight, east facing ones in the morning, west facing in winter afternoons while covering north facing ones year round and closing them all at light. Using thick curtains to trap the heat when it's dark is helpful.
posted by plonkee at 7:38 AM on April 19, 2021
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posted by kate4914 at 2:22 PM on April 17, 2021 [7 favorites]