Insulating effect of carpet vs linoleum.

[Kevin]

I an getting near the point of having to decide what type of flooring to install on the concrete slab in my basement addition. Ignoring for the moment other considerations such as durability, I'm wondering about the 'heat sink' effect of the slab, and whether carpeting will have an effect. I seem to recall that at the time the Title 24 calcs were done, being told that an exposed slab, would have a positive effect on the calcs, but a carpeted floor wouldn't figure into the equation.

This addition is in the half of the basement area that wasn't already a finished room. The pre-existing half does have carpet, and in the hot weather we are currently experiencing, I'm noticing that the new room does stay cooler than the pre-existing room.... (I don't have a/c for the lower half of the house). I would like to keep it that way, and am wondering if carpeting will have a noticable effect. My alternative to carpet would be real linoleum, which I'm assuming would have a very limited, insulating effect.

Would appreciate any comments, especially from those who do title 24 calcs for a living.

TIA Kevin

[Stormin Mormon]

Years ago, I lived in a building that had formerly been a car repair garage. Had cement floor. One cold winter day, I was laying on the bed, watching television. A space heater was keeping the ceiling warm, but the floor was bitter cold. At one point, I noticed that my left foot was not as cold as my right foot. I looked down, and noticed that left foot was on a carpet scrap plus the room carpet. Right foot was only on the thin carpet. So I moved the carpet scrap so it could be under both feet.

Since that time, I've been a big believer in having a big thick carpet sample where my feet hit the floor, stepping out of bed.

Anyhow, I find that carpeting does have insulation value. Use that information as you wish.

[Tony Hwang]

Hi, My house has fully developed basement with proper heat/cooling duct work and gas fire place. Floor is think rubber underlayed carpet. Even in winter(temp. ~-30). it is pretty cozy down there.

[bob haller]

carpet will feel warmer but, in a non AC space it may develop a odor / mold. from presence of excess moisture

[dpb]

Kevin wrote: ...

That doesn't make any sense--if a slab has an effect but changing the slab to something else doesn't, then that fact "has figured into the equation".

...

And, it'll be exactly the opposite effect when the cold weather arrives. Of course carpeting has an insulating effect; just how big an "R" factor it is depends mostly on how think the pad used is; the carpet itself is a lesser (but not totally negligible) amount.

[Tony Hwang]

Hi, Here our climate is very dry. We need humidification during winter in the house otherwise you are going to have bloody nose(too dry!)

[Kevin]

I do have heat in that area. As part of this project, I installed two new heaters, one for each level, but I only installed a/c for the upper level.

Carpet certainly does have a percieved warmer feel, but my question is, will the moderating effect that masonry has on actual temperature and rate of temperature change, be negated by installing carpet.

Kevin.

[Kevin]

What I meant, but perhaps didn't say very well, is that a exposed concrete slab would be figured into the calculations, and would have an effect that would help me meet the title 24 requirements. However if I specified carpet, then it wouldn't be considered.

Kevin.

[dadiOH]

Because the warm in your feet isn't being sucked out by the slab. They are being *INSULATED*.

Negated? Who knows. Affected? Yes. Carpets and rugs insulate. So does any padding.

How much? Depends on the material, thickness and type of the carpet and padding. Big difference between glued to slab, skimpy, low pile commercial carpet and a densely woven, high pile wool carpet on a thick foam pad.

[ransley]

Where do you live, I live where winter heat bills kill you, zone 5. Where I am at about 5ft below grade ground temp is never above 50-55 so it cools year around and concrete doesnt insulate much, maybe R 1 for 4 inches. Foam padding is an excelent insulator maybe R 3 for 1/2" and carpet itself maybe R2 I will guess. Carpet and padding makes my basement much warmer in winter since that 50f temp is being held back. If you live south where winter heat is a few dollars and AC is the big money then tile it, linoleum is best, the plactic tile has very little if any insulating value but up here in the midwest carpet with the thickest foam will save money on utilities. The foam pad per inch has the highest R value. Keep a good dehumidistat handy and a dehumidifier, you dont want above 65-70% or mold might grow. One idea might be a foam pad and area rug you roll up in summer, portability is also a good idea for when a pipe breaks, one leak and wall to wall is trash. I just use a bunch of area rugs and padding, mainly for the winter cold.

[fftt]

R value for typical concrete is really low. Less than .1 per inch.

Which is why in cold climates it makes sense to insulate under a new slab on grade.

cheers Bob

[Stormin Mormon]

Winter time, I find cement floors to be killer cold. I've not heard of insulating under slabs, though it makes good sense.

[aemeijers]

Or have a really deep basement, and insulate the heck out of the side walls. When it is subzero outside, that 50-degree dirt 10 feet down looks pretty good.

That is the basic premise of earth-berm houses, after all....

-- aem sends...