Tag: Building Science

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Blower Door Testing for Contractors, Should You Own One?

This post first appeared on the Green Building Advisor Website.

I had the opportunity to interview Gary Nelson, one of the founders of The Energy Conservatory and Minneapolis Blower Door a few years ago.  An Interview with Gary Nelson-NorthernBuilt.  During the interview, he made the comment that his hope for the blower door when it first started appearing in the market was that every contractor would own one and that testing both existing and new homes would become a common practice.  That was 40 years ago.

We haven’t got there yet, but there are more and more contractors purchasing the tool and there are many online videos and webinars showing how a blower door is set up and used.  In this blog, I’ll discuss how to perform basic diagnostics on a home using a blower door.  Methods used to find air leaks, a short discussion on zonal pressure testing, and different tasks that the manometer can perform, all topics I think a contractor that owns (or wants to own) a blower door should be familiar with.

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The Effects of Poorly Installed (or Missing) Insulation

I was taught many years ago by an older fiberglass insulation contractor the importance of a quality insulation job.  His biggest piece of advice, FLUFF, DON’T STUFF!  Poorly installed insulation can have a big impact on the overall performance of a home.  In this blog, I’m going to show you mathematically how a small insulation deficiency can have a big effect in how a home performs.

This thermal image is a good example.  This was a brand-new home where I was performing a code required blower door test.  I ran around the home with my thermal imaging camera before starting the test and thought I might be able to use this image to show thermal bridging, which it does a good job at, but if you study the pic a little closer, we see several areas where the fiberglass insulation was poorly installed.  Compressing (not fluffing) the product creates areas of cooler temperatures in the insulation batts.  The dark area (at the ceiling on the right side of the photo) shows an area of missing insulation.  What effect does this poorly installed insulation have on the overall (effective) R-value?  We can show the results mathematically.

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Concrete Free Slab on Grade House – Five Years Later

This post first appeared on the Green Building Advisor website.

In June of 2019, we began a project we called “The Concreteless Slab on Grade Home”.  Kiley Jacques, (now the editor of Green Building Advisor), covered the project in an article she wrote back in early 2020.   Another Take on a Concrete-Free Slab – GreenBuildingAdvisor   I wrote a piece on the project for this blog, Construction Design-Concrete-less Slab on Grade – Northern Built.  This year is the Five-year anniversary of the start of that project.  I thought it would be a good time to revisit, discuss what worked, what I would change, and talk about a very unexpected series of events that could have been a major problem.

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What’s the Difference Between R-Value and U-Factor?

This post first appeared on the Andersen Windows and Door Website.

We were taught in junior high that hot air rises, the key to that phrase is air.  Heat itself moves from someplace warm to someplace cool.  A good example of this happens often in cold climates.  When standing in front of an old window on a cold night, you feel a chill.  This chill is the result of heat leaving your body and moving towards the colder surface of the window glass, heat moving from hot to cold.  To slow this movement of heat, we use insulation, by putting on another layer of clothes, we reduce or resist the movement of heat, we have added R-value.

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Building Codes and Building Science are Beginning to Better Align

This post first appeared on the Green Building Advisor website.

I’ve heard Mike Guertin mention that every home built is a building science experiment.  It can take some time for problems in buildings to be known.  For instance, a bad detail on a window installation, like shown in this photo, could take more than 20 years to present as a problem.  If the problem is being repeated, building science might identify the issue and propose a change.  Eventually, the change may end up in the building codes, but this whole process is slow.

That being said, there are many building science principles that we have figured out, with several already added to the codes.  Some have been known about for decades but are still slow to be adopted.  Let’s discuss a few of each.

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How Well Do You Know Building Science?

This post first appeared on the Green Building Advisor Website.

The International Builders Show took place from February 27th through the 29th, 2024 in Las Vegas, NV.  The past couple years, Huber Engineered Wood has held a building science trivia game in their booth.  The game is played using an app on a cell phone, questions are answered by contestants and their score is based both on how quickly the question is answered and whether the question was answered correctly.  The game is just for fun, though there are some bragging rights if you are able to beat the on-stage contestants.  This year, the on-stage players were Jake Bruton, Steven Baczek, Peter Yost, and Ben Bogie with Tate Hudson from Huber asking the questions.  (Jake has this year’s bragging rights.)

I thought it might be fun to have a version of building science trivia here on the Northern Built Blog.  Some of the questions being asked are from the game played in the Huber booth, others are questions that were asked during another building science trivia game played a recent BS and Beer-Northern Minnesota meeting.  The game is just for fun, you keep track of how many you get right.  The answers (along with a little more in-depth information about the answer) will follow the quiz.  Here we go.

  1. The climate zone map located in Chapter 11 (Energy Efficiency) of the 2021 International Residential Code Book contains how many different climate zones?
    1. 8
    2. 9
    3. 14
    4. 19

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Common Building Science Mistakes to Avoid

This blog post first appeared in two issues of Fine HomeBuilding Magazine: Issues 321 and 322.  Part of a series that included 17 short articles written by 7 different authors.  My first contribution appeared in the letters and reader feedback section of the February/March issue, titled “The biggest mistake of all?”  You can read that post here. 

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Ice Dams-Why They Form and How to Reduce their Risk

There is a lot of confusion as to why ice dams form on roofs in cold climates.  This is understandable, some years we experience heavy ice dams, other years have little to no issues.  Changes in weather from year to year can have a major impact on their formation.  I’ve seen new homes with ice dams that are completely related to winter freeze/thaw cycles.  That being said, most ice dam issues are directly caused by certain characteristics of the home, namely insulation levels and air tightness.

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Construction Design-Problems with Attic Trusses

This post first appeared on the Green Building Advisor Website

Attic truss, also known as a room-in-attic truss are a way to create a living space without the need to add a full second story to a home.  These factory-built roof systems simplify a roof buildout and are engineered to meet the structural requirements of your local codes and conditions.  I commonly see them used for bonus rooms over garages and integrated into slab-on-grade homes to add living space without needing to add to the height of the building.

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Vapor Control in Walls with Continuous Insulation-IRC Chapter 7 vs Chapter 11

This article first appeared in the January/February 2024 issue of the Journal of Light Construction.  www.jlconline.com

The International Residential Building Code is supposed to provide clarity into how builders construct homes.  In the IRC’s own words, “The IRC was created to serve as a complete, comprehensive code regulating the construction of single-family houses, two-family houses (duplexes) and buildings consisting of three or more townhouse units.”  Usually, the codes do a decent job giving us options on how we should build homes with the occupant’s safety and health as our number one priority.  Codes also address energy efficiency and building durability.  Sometimes though, codes can be quite confusing.  How we handle vapor retarders when using continuous insulation is one of those areas.

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