R value

Brad White_191

Hi Jim-

As Mike pointed out, the R value varies with type of stone. I tend to use 0.08 per inch, about the same as concrete of similar density. As D.S. asks, the quality and homogeneous nature of the stone is critical. Gaps? Ugh.

Your 18 inch wall would have a net R value of 1.44 but do not forget your indoor air film (0.68) and your outdoor air film (0.17 with a 15 MPH wind).

You get 0.85 R value for showing up and for having the wisdom to live on a planet with an atmosphere.

I would figure your total R value (bare stone wall plus air films) at 2.29. The corresponding u-factor is 0.437.

Frankly, I have to tell you, I have done several historic restorations where the new Low-E windows had better heat retention than the walls. As Rob said, mass is your friend here.

Jim Pompetti

R Value

What is the R value of a 18" stone wall

Jim_64

Not much. "Rule of thumb" is around R-1 per foot of thickness.

Here's a good Stone R-Value Table

Unknown

at that point, the mass is more important than the R value, but that's a way more complicated question.

WV EGBERT_2

Dry laid stacked wall in a old farmhouse foundation?
Or a well built, fully pointed with no air gaps?

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Jim Pompetti

Thanks

All . Nice to hear from you Brad, Hows the family


Ala Famglia