What is R-Value?

This is the first in a series of blogs I’ve written for Rockwool and the R-Class Builder Program.  If you are not already a member, you can join at this link, Rockwool R-Class.  The R-Class program is free.

What is R-value?  I write often about different insulations, how they perform, where they should and shouldn’t be used.  I think this blog post should go back to the basics and talk about what is R-value, how it is calculated, and how much is needed.

This concrete foundation is not insulated, concrete has a much lower resistance to heat flow (R-Value) than the insulated wall. This becomes evident when using thermal imaging. Heat is leaving this structure through the concrete. Insulation will slow this heat loss.

Continue reading “What is R-Value?”

Building Science-A Benefit of Exterior Insulation

I’m a big fan of exterior insulation.  It’s rarely used in my area, mostly because the State of Minnesota has eliminated that code requirement.  It has to to with our wide use of polyethylene sheeting as a vapor retarder on the warm in winter side of a wall assembly and then adding a low permeance plastic insulation product as exterior insulation.  These plastic foams would be the choice for most contractors, lower cost and easy to source.  Very slow vapor movement in either direction when a wall assembly becomes wet.  This posting isn’t going to get into the foam insulations, but more into what exterior insulation can do for a home. Continue reading “Building Science-A Benefit of Exterior Insulation”