Getting to Know Spider Insulation

Posted on May 05,2015 by AlexWilson in blown-in fiberglass

We’ve just completed the installation of a relatively new and (at least in New England) little-known insulation material called Spider. As a reminder, the house we are renovating (really rebuilding) in Dummerston, Vermont, has provided an opportunity to try out dozens of innovative products and materials that I’ve long researched and written about in Environmental Building News.

Resilient Design: Dramatically Better Building Envelopes

Posted on May 05,2015 by AlexWilson in design

When most people think about resilience — resilience to storms, for example — they think only about resilience during the event. Equally important, if not more important, I believe, is resilience in the aftermath of that event. Hurricanes, ice storms, blizzards, wildfires, tornadoes, and other natural disasters not only have an immediate impact, for which we may or may not be able to prepare, but they often have a much longer-term impact, usually through extended power outages.

Weatherization’s Home-Stretch Recovery

Posted on May 05,2015 by Fretboard in American Recovery and Reinvestment Act

The Weatherization Assistance Program – which emerged as a major administrative challenge and political target after its budget vastly expanded under the federal stimulus bill – turns out to be meeting expectations.

Books on Insulation and Energy-Efficient Building

Posted on May 05,2015 by user-756436 in energy-efficient home

Two new books that might interest green builders recently caught my eye: The BuildingGreen Guide to Insulation Products and Practices by Alex Wilson and The JLC Guide to Energy Efficiency by the editors of The Journal of Light Construction. Full disclosure: I was a minor participant in the creation of both books. At Wilson’s request, I reviewed portions of his manuscript before publication and provided feedback. I also wrote several of the articles appearing in the JLC book.

Irish Passive House Raises Bar for Eco Design

Posted on May 05,2015 by GBA Team in Construct Ireland

Reprinted with permission from Construct Ireland magazine. Sally O’Leary says that when a site became available near the site of an old family home, she couldn’t pass up the opportunity to buy it. She’d been looking for a site to build on with her husband John. “We always wanted energy efficiency, I think nowadays that’s something that people have to do," she says.

BEopt Software Has Been Released to the Public

Posted on May 05,2015 by user-756436 in BeOPT

UPDATED February 1, 2012 In 2004, researchers at the National Renewable Energy Laboratory (NREL) developed BEopt, a software program that finds the least-cost solution to designing a zero-energy house. Now that the software developers — a team that includes Craig Christensen and Scott Horowitz — have spent seven years improving the program, it has finally been released to the public. The development of BEopt was funded by the U.S. Department of Energy.

How to Install Rigid Foam Sheathing

Posted on May 05,2015 by user-756436 in EPS

UPDATED on March 18, 2015 What’s the best way to install foam insulation on the outside of a wall? Although GBA has published many articles and videos on the topic, we continue to receive frequent questions from readers asking how to install rigid foam sheathing on exterior walls — so it’s time to provide a primer on the topic.

Air Sealing With Sprayable Caulk

Posted on May 05,2015 by user-756436 in air leakage

Homes insulated with fiberglass batts are leakier than homes insulated with cellulose or spray polyurethane foam. Until recently, fiberglass batt manufacturers shrugged off the damning air-leakage data, insisting that their batts could deliver the R-value promised on the packaging — and then changed the subject.

Study: Codes Really Can Improve Energy Efficiency

Posted on May 05,2015 by Fretboard in energy code

What once might have been broad assumptions about the merits of energy efficiency provisions in building codes now have the backing of research. A San Francisco-based organization called Climate Policy Initiative recently completed an analysis that compares states with energy codes to those without.

Getting Insulation Out of Your Walls and Ceilings

Posted on May 05,2015 by user-756436 in exterior insulation

More and more builders have realized the advantages of leaving stud bays empty and putting all of a home’s insulation outside of the wall and roof sheathing. If done correctly, exterior insulation can help produce a building that is almost airtight, very well insulated, and almost immune to water damage.

Installing Fiberglass Right

Posted on May 05,2015 by user-756436 in air barrier

Of all of the commonly used types of insulation — including cellulose, rigid foam, and spray polyurethane foam — fiberglass batts perform the worst. As typically installed, fiberglass batts do little to reduce airflow through a wall or ceiling assembly; rarely fill the entire cavity in which they are installed; and sometimes permit the development of convective loops that degrade insulation performance. Knowing this, why would any builder choose to install fiberglass batts? The answer is simple: because fiberglass batts cost less than any other type of insulation.

Insulate the perimeter of all concrete slabs

Posted on May 05,2015 by Peterbilt in Kitchen or bath addition

**Before pouring a concrete slab, install rigid foam insulation along its perimeter.** If the slab isn't isolated by foam, there will be a thermal bridge to the foundation or soil. This makes the edge of the slab cold, compromising energy efficiency and possibly raising the temperature of the slab perimeter above the due point. This could cause condensation and mold growth. The insulation should separate the slab perimeter from all exterior foundation walls, footings, or soil.

Insulate basement walls to at least R-16

Posted on May 05,2015 by Peterbilt in Kitchen or bath addition

**Uninsulated basements can contribute to up to 1/3 of home heating costs.** Insulating basement foundation walls on either the interior or exterior will produce equal energy-savings. Make sure the insulation runs continuously from the foundation’s footing to the underside of the subfloor. Eliminate air leaks with expanding foam or by filling joints with tape and mastic. Pay particular attention to band-joist areas.

Exceed code minimums for wall insulation

Posted on May 05,2015 by Peterbilt in Add a floor above

**Although they’re theoretical, whole-wall R-values are closer to real life insulating values.** Consider a 2x4-in. wall framed 16-in. O.C. and stuffed with high-density R-13 fiberglass batts. Assuming a perfect installation, its whole-wall insulation value is closer to R-10 (25% to 30% less) due to thermal bridging caused by wall studs, plates, and the band joist. This problem is particularly acute with steel framing. And, more difficult to measure, the true insulation value likely is even less because of poor installation, air infiltration, wind wash, air-convection loops, etc.

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