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Why Knowing Your Climate Zone is Important

Figure N1101.7 (R301.1) Climate Zones-2021 International Residential Code (IRC)

This climate zone map is published by the American Society of Heating and Air-Conditioning Engineers (ASHRAE) and is included in the International Residential Code, chapter 11, Energy Efficiency.  ASHRAE’s purpose is to create standards of how an engineer or HVAC professional calculates and designs heating, air conditioning and ventilations systems to match the insulation, air sealing, and moisture profile of a building.  When designing these often-complicated systems, where the structure is located becomes key, this is the reason the map was created.

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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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Upgrades that Effect Energy Loads

This post first appeared on the Green Building Advisor Website.

As homeowners, builders, and/or designers, how do we choose the right products or assemblies that provide the best energy performance?  How does a code minimum designed wall perform?  How about changes in ceiling insulation R-values?  What if we decide to increase the air tightness?  How about triple pane windows?  There are several ways in which product and assembly upgrades are chosen.

  1. First is experience. In having the opportunity to be in more than 100 homes a year performing energy assessments/audits and building investigations, I see both successes and failures.
  2. Being familiar with the different products on the market is important. As an example, selecting the right product for a given budget that can be installed over the board sheathing of an existing home to provide both bulk water management and air control.
  3. Using energy modeling software to quantify the decisions is helpful. The easiest way to decide which improvements to implement is by creating a baseline (code minimum) model of the project, then key in the proposed upgrades to see how the model changes.
Air leaks, thermal bridging, and low R-values all affect the operational costs and comfort for this home.

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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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A 2021 IRC Code Oversight Could Lead to a Risky Roof Assembly

This post first appeared on the Green Building Advisor Website.

I’ve been working on a future article for Green Building Advisor that has a working title of “Problems with Attic Trusses”.  During research for the piece, I found myself reviewing the ratio rules for hybrid roof insulation strategies.  GBA has two really good articles on the topic:

Combining Exterior Rigid Foam With Fluffy Insulation – GreenBuildingAdvisor by Martin Holiday

The Ratio Rule for Hybrid Roof Insulation – GreenBuildingAdvisor by Allison Bailes

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Membranes…Interior Air-Control Strategies That Can Work

This article first appeared on the Green Building Advisor Website.

I’m from Minnesota, one of the few areas in the lower 48 that still regularly uses polyethylene sheeting as a vapor retarder, we’ve become very good at detailing these interior membranes for use as an air barrier.  (The practice is also very common in Canada and Alaska.)  The average blower door test I conduct for new homes in my market has now moved below 2 ACH50, most achieving these scores only using an interior air control strategy.  I don’t recommend using poly in most cases, instead I suggest moving to a class II vapor retarder, (smart, variable, and responsive vapor retarders), these products can also be used for air control.  Installing the two products is similar, so, what are the tricks to an effective interior air barrier installation?

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Peak Electricity Load Control Programs-a Solution for Home Electrification?

There are times during the day when electrical demand is high, during the morning when a large portion of the population is getting ready for work.  The lights come on, there’s an increase in hot water use, people are making coffee, or using the microwave or an electric stove or oven.  All these add to a morning increase in electricity demand, a peak in usage.  A similar increase occurs in the evening when people return home from work.  The weather can also influence electricity demand, hot weather will increase the need for air conditioning and maybe dehumidification.  Overnight usage is typically low periods of demand.

The hourly electricity consumption from an actual energy audit I recently conducted showing increased usage based on time of day.

A problem with periods of high electricity demand, utility companies often need to bring peaking plants (short term power generating plants) online to satisfy short periods high electricity usage.  These power plants are sometimes only used during peak loads and often have higher air pollution rates than the plants designed to operate all the time.  If demand isn’t met by the peaking plant, the provider must purchase power on the open market.  Sometimes the electricity rates during peak electricity usage are purchased for dollars per kilowatt, and then are sold back to the customer in pennies per kilowatt.  Not the best business model. Continue reading “Peak Electricity Load Control Programs-a Solution for Home Electrification?”