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.

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Construction Materials-Cavity Insulation

Heat wants to move from someplace hot to someplace cold.  It’s desire to reach equilibrium is one of the principles of the second law of thermodynamics.  We have many methods and materials we use in construction to try to slow this movement.  It’s expensive to condition a space and we want to hold on that space conditioning for as long as possible.  One way we try to slow heat loss or gain is to prevent the wind from blowing through the home.  Another is to shade the sun from beating through a window on a hot, sunny day (in some climates at certain times of the year, the sun can be a blessing).  Insulation is one of the big ones we use to provide comfort to homeowners.

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Construction Design-The Anatomy of a Well-Built Wall

I’m a fan of mineral wool insulation, specifically the Rockwool brand.  Over the next few months, I’ll be writing a series of blog posts discussing tips, tricks and the tools used to work with this insulation made from rocks and steel slag a byproduct of the steel industry.  Before we get into those topics, I want to discuss the Rockwool products I use, the building science behind the how these products work in a wall and the characteristics of the insulation, all of which can create a well-built wall assembly.

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Barndominium Part 4-Insulation and Air Control

This post first appeared on the Green Building Advisor website.  Residential Post-and-Frame Construction, Part 5: Insulation and Air-Sealing – GreenBuildingAdvisor

Cavity Insulation

I was brought on the barndominium construction team after many decisions were already in place.  The design was, for the most part, finished.  Many of the assemblies had been designed, such as the decision to use laminated posts six foot on center with the horizontal wall girts both inside and out.  The original plan for the insulation was to use up to seven inches of closed cell spray foam in the walls.  I was able to change the insulation strategy with a plan for a more “forgiving” assembly.  We chose to go with Rockwool’s 7.25-inch ComfortBatt, which has an insulation value of R-30. Continue reading “Barndominium Part 4-Insulation and Air Control”

Construction Design-Randy’s Dream Design

Guess what?  I just won the lottery!  (Not really, but for the purpose of this blog, let’s pretend.)  I’m looking to build myself a new home.  I have choices.  I could build a McMansion with plenty of space I don’t need and will never use.  I could concentrate only on the interior finishes and how the house looks.  If you’ve ever read my blog, you already know what direction I’ll take.  The house won’t be big, a couple thousand square feet is plenty for me, maybe a rambler with a second story over part of it built on a slab, no basement or crawlspace.  Being a BS* guy, I would make an invest in the stuff that is hidden, those pesky control layers I often talk about.  It would be based on the Pretty Good House concept. Continue reading “Construction Design-Randy’s Dream Design”