A roof’s purpose Before you choose a roof design for a new building, you should understand the purpose of a roof. The primary purpose of roof is to shed rainwater and snow. A secondary purpose — and a less appreciated one — is to provide shade. A roof’s enemies Moisture, and to a lesser extent heat, can degrade[…]Read more
Building assemblies can get wet Building scientists assume that some rainwater leaks through the cladding or roofing and that water vapor migrates through insulated building assemblies, sometimes condensing within those cavities. These two phenomena both can dampen building assemblies. What are rainscreens? Builders often provide a 3/4-inch air space between siding and the water resistive barrier (WRB) as[…]Read more
Old and new water barriers Once upon a time, builders stapled 15-pound asphalt felt to wall and roof structural sheathing as a water-resistive barrier (WRB). The 2012 International Residential Code (IRC) still specifies: “one layer of No. 15 felt… or other approved water-resistive barrier.” Most builders used perforated felt to allow water vapor to escape[…]Read more
Introducing 29 New RESNET CEU Courses Attention raters, rater trainers, and RESNET training organizations: Saturn Resource Management now offers 29 new short courses that qualify for RESNET CEUs. These short e-learning courses mix media such as slides, slide narrations, videos, illustrated text, exercises, and quizzes. Our e-learning lessons contain between 15 and 25 slides. We[…]Read more
Focus on the Envelope Home owners and builders seldom give the building envelope the priority it deserves. The insulation, air barrier, windows, and doors are the most important features of a new home. These envelope features determine a home’s energy efficiency and comfort. They’re also permanent and may never change. Homes with better thermal resistance and airtightness need smaller HVAC systems.[…]Read more
What is a credit? Saturn uses a formula to calculate how many average hours of student effort that a lesson or course requires. Of course, effort hours differ among different students, but our calculation is a good average. The easiest way to understand the convoluted world of educational credit is to explore some definitions.
The Experimental Findings Building Science Corporation (BSC) published a recent report that spawned a Journal of Light Construction (JLC) article called “Moisture in Fat Walls”. Two of the three walls studied are double walls with R-values in excess of R-40. The setting for the buildings studied is Massachusetts.
Hey, I would really appreciate some feedback on this method of evaluating combustion air. Unnecessary Holes in the Building Contractors often cut combustion-air holes in ceilings, floors, walls, and doors without knowing whether the combustion appliance zone (CAZ) needs additional air. These new openings can lead to unintended consequences like pressurizing or depressurizing the CAZ[…]Read more
Builders install a variety of products on the exterior of foundations, above-grade walls, and roofs as water-resistive barriers (WRBs), required by the International Residential Code (IRC). Water-resistive barriers are also called weather-resistant barriers, but the former term is now considered preferable. WRBs are buildings’ last and primary exterior water barrier. WRBs vary widely in their vapor[…]Read more
The Act and Its Downfall First off what is the Energy Efficiency Improvement Act of 2014? The bill contains 4 parts. Title I establishes a voluntary, market-driven approach to aligning the interests of commercial building owners and their tenants to reduce energy consumption. Title II exempts large grid-enabled electric-resistance water heaters from regulation if they contain thermal-storage[…]Read more
A Collection of Adult-Learning Research Results The book, Building Expertise by Ruth Colvin-Clark, offers one of the best summaries of adult-learning (pedagogy) research available. Like so many fields adult-learning pedagogy is hindered by dubious assumptions and outdated traditions. Ms. Colvin-Clark challenges these old models with recent research about how students, and especially adults, learn. Building Expertise is based[…]Read more
Relative Humidity, Temperature, and Moisture Content This is Part 2 of a two-part series on cellulose insulation and moisture. Cellulose insulation is a hydrophilic material, meaning that absorbs moisture readily. Under certain conditions condensation dampens cellulose insulation causing permanent damage due to shrinking, slumping, and very slow drying. Moisture adsorption into a hydrophilic material, expressed as[…]Read more
This is a two-part blog about hygric buffering, cellulose wall insulation, and moisture problems in high-performance buildings. Why not to install cellulose insulation in deep wall cavities Cellulose shrinks, slumps, and dries very slowly after wetting. Deep wall cavities are have more risk because the outdoor side of the wall is colder than shallower cavities. Voids left by[…]Read more
We’ve been dealing with the ASHRAE ventilation standard for a while. 62-89 goes way back. We used that one for a long time, and it worked well enough. After we taught our students how to use 62-89, they could understand it and implement it. Then came 62.2. We first wrote about 62.2-2010 in this blog back in[…]Read more
KM’s History Knowledge management has a long history, including apprenticeship programs, discussion forums, corporate libraries, professional training, mentoring programs, and now data bases designed to manage knowledge. Computers and software have enhanced our ability to manage knowledge. The financial services industry was the earliest adopter of computer-based KM. Academics adopted KM as a research topic and course topic around the[…]Read more
What the EPA Says EPA’s new final rule on Carbon Pollution Emission Guidelines for Existing Stationary Sources: Electric Utility Generating Units “Energy is transmitted, not electrons. Energy transmission is accomplished through the propagation of an electromagnetic wave. The electrons merely oscillate in place, but the energy – the electromagnetic wave – moves at the speed of[…]Read more
This post is a revised version of the last post about Evaluating Combustion Air. The changes are a result of the many discussions I had with the experts in the previous post. You know who you are. Thank you. I continue to value your suggestions. Feel free to comment and thanks again.
What is a Helical Pier? A helical pier is a pier that installers screw into the ground using a large drill motor. Helical piers work well in situations where the surface soil isn’t sufficiently supportive for a conventional foundation. When installers can reach stable soil 10 to 60 feet deep, the helical pier’s helices will[…]Read more
The Good News for Energy Conservation The time value of money has always worked against energy conservation. Traditionally a dollar today is worth more than a dollar in the future by a certain percent, known as the interest rate. The European Central Bank (ECB) declared this week that, for the present, this pillar of the worldwide[…]Read more
A Proposal for Energy-Conservation Loans The following is a proposal for a revolving loan fund that a State, municipality, or utility organization could administer. This proposal resulted from a long conversation between John Krigger and Gary Klien, who at the time worked for the California Energy Commission.