R-Value: A Measure of Insulation Effectiveness

From mud and straw to how we measure insulation effectiveness today

R-values are covered extensively but I wanted to distill the information in a way that could be easily understood. If you like the post, please support me by liking it.

R-values measure the effectiveness of insulation. Thousands of years ago, both the Egyptians and Vikings insulated their homes with mud and the latter also used straw. Mud has a negligible R-value of R.125-R.25 per inch while the R-value of straw is R.94-R1.38. Mud is not a good insulator, but it is good at storing heat or cold. It has high thermal mass, similar to a sidewalk on a summer evening, that is still hot from the daylight sun. Mud when combined with straw is a very good thermal and sound insulator, on par with some of the insulation that is available today. Today, the most common insulation materials used in homes include fiberglass, mineral wool, cellulose, and foam and in colder climates, R-values for walls and floors can start at R30 and go up from there.