What is the R-value of soil?
0.25 to 1.0 per inch
While it seems soil would be an effective insulator, it has an R-value of only 0.25 to 1.0 per inch at 20% moisture content, according to inspectapedia.com – which is much less than rigid foam insulations (EPS insulation, by comparison, has an R-value of about 4.4 per inch).
What is R-value in pavement design?
The R-Value test measures the response of a compacted sample of soil or aggregate to a vertically applied pressure under specific conditions. This test is used by Caltrans for pavement design, replacing the California bearing ratio test.
What is the R-value of compacted soil?
A short answer to the R-Value of Dirt – about R 0.125 to R 0.25 per inch. Some sources we researched assert that “one inch of ‘insulation’ is equal to about two feet or more of soil.
What is the typical range of CBR value for subgrade?
CBR values for common soil subgrades can be estimated according to the USC soil types, for example: clay around 2%, sand from 7% (poorly graded) to 10% (well graded), well graded sandy gravel 15%, clayey sand 5-20%, silty gravel 20-60%, gravel from 30-60% poorly-graded to 40-80% if well-graded.
What is the R-Value of 2 inch foam board?
A wall utilizing STYROFOAM T-MASS Technology with a 2-inch exterior layer and a 4-inch interior layer of concrete along with a 2-inch layer of STYROFOAM extruded polystyrene insulation would result in a material R-value of approximately 11.33.
Can you use sand for insulation?
Anyone who has walked on a hot, sunny beach knows that sand is a good insulator. Dry coarse grained sand may be used as a substitute for the insulation required by code in a buried pipe situation. The sand should have a maximum particle size of 1/4” and a moisture content of 1% or less.
What is the R-Value of concrete?
Tables of Building Material R-values
| Material | Thickness | R-value (F° · sq.ft. · hr/Btu) |
|---|---|---|
| Concrete Masonry Unit (CMU) | 12″ | 1.28 |
| Concrete 60 pounds per cubic foot | 1″ | 0.52 |
| Concrete 70 pounds per cubic foot | 1″ | 0.42 |
| Concrete 80 pounds per cubic foot | 1″ | 0.33 |
How is R-Value tested?
The R-value of a material is determined by holding temperatures on both sides of a material, typically 50F and 100F, which has a mean temperature of 75F, and measuring the heat flux that crosses the sample. This is the standard at which all insulations are tested and recorded.
How do you test subgrade strength?
Methods to Properly Evaluate Subgrade Strength & CBR
- Allows for the physical evaluation of underlying soils through additional laboratory testing.
- Ascertain soil strength at various depths through N-values (blow counts) by a weighted hammer that can be translated to estimated values for subgrade modulus and CBR values.
What is the R-value of 3.5 batt insulation?
Standard 3.5-inch thick fiberglass insulation has an R-value of 11, and fits neatly in two-by-four wall stud spaces. It is produced in R-values from 11 to 49, with thicknesses ranging from 3.5 inches to 14 inches.