Tag: Insulation

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Rockwool-Not Your 1950’s Mineral Wool Insulation

This post first appeared on the Rockwool R-Class blog.  www.rclass.rockwool.com/blog

If you’ve been in the construction industry long enough, chances are you’ve had to remove an old mineral wool insulation product during a renovation.  I know I have.  It’s itchy, easily falls apart, and it often doesn’t completely fill a cavity bay.  I’ve had many conversations with other builders who will not consider using a mineral wool product because of their past experiences with the older mineral wool insulations.  I can tell you; the old stuff is nothing like modern stone wool.

Itchy, fragile, and does not fill an entire 2×4 cavity bay. This R-7 batt of mineral wool insulation from the 1950’s is much different than the modern stone wool equivalent.

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Windows-Water and Air Sealing

I’m going to make a statement that not everyone will agree with, windows leak water.  Not all are leaking now, some will develop the leak later, as the window and the sealing products used to install the window age.  The leak may be an error or failure in the installation, or it could be the window itself that is leaking.  It could be a design error, water funneling off a roof over a window, such as in the photo.  The leak may only be an incidental amount of water, or it could be a major bulk water concern.  The leak may also only be active during the once every ten-year major rain fall event.  The point is windows will leak water.

Photo by Eric Strommer-Strommer Home Improvements

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The Thermal Bridge

Thermal imaging is an awesome tool, it can be used to find areas of missing insulation and other temperature anomalies in the building shell.  It can help us find issues with electrical, plumbing and heating systems.  And when used in conjunction with a blower door, we can often “see” the air leaks.  The photo below was taken without the assistance of a blower door, I was at this new home to conduct a blower door, but the test hadn’t begun at the time this photo was taken, can you say thermal bridge!

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The Diminishing Return of Insulation

Insulation and R-value go together like hard work and sweat.  R-value is, of course, the resistance to heat flow.  We’ve been taught to think more is better, which is true to a point.  I’m changing the insulation in the wall of my home from R-7, originally installed in 1952, to R-15, and I’m excited to see how much more comfortable my home becomes.  There is an argument that at a certain level, more insulation will cost dollars to save pennies.    At what point do we reach diminishing returns?

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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 Design-Wind Washing

Wind: The natural movement of air relative to the planet’s surface.

Washing:  A method of cleaning.

Wind Washing:  Cleaning using air?

Well, not quite.  Wind washing with regards to insulation is the ability of air movement to degrade the effectiveness of an insulation.  We will get to that in a little bit.  First a quick lesson on how fibrous insulations works.

A close-up of Rockwool ComfortBatt showing the fibers and small air pockets.

We use insulation to slow the movement of heat through our building assemblies.  Heat will move in three ways, conduction (heat moving when objects are in contact with one another), convection (heat transferred by moving air), and radiation (heat moving through spaces).  Fibrous insulations forces heat to move through fibers and small pockets of air, which slows heat movement in both radiation and conduction and prevents heat transmission by way of convection. Continue reading “Construction Design-Wind Washing”

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Construction Design-The Effect of Windows on Wall R-Values

I’m about to start a remodel project of the family room in my home.  Not your normal fresh paint and new floor covering update, but a complete gut down to the stud renovation.  New electrical, new drywall and no more popcorn ceiling.  I’m curious as to what my effective R-value of the exterior walls will be when I’m done with the space.  This includes the windows.  I figured I’d share my calculations with you.  This post is math heavy, if you’d like to skip the math, read the final five paragraphs.

Progress picture of the exterior work on my small cape from 2019.

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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”