The most recent blogs at Green Building Advisor

Green Home Appraisal Woes

Posted on September 7, 2010 by Scott Gibson in Q&A Spotlight

Passive solar designs that include generous amounts of insulation can save homeowners a great deal of money in operating costs over the life of the house. But getting banks to approve loans that reflect somewhat higher construction costs can be a struggle, sometimes forcing builders to dial back their plans and deliver a less efficient house.

This dilemma was at the heart of a question from a green builder and the topic of this week's Q&A Spotlight.

Using Rigid Foam As a Water-Resistive Barrier

Posted on September 3, 2010 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Do foam-sheathed walls also need housewrap? There’s no simple answer to the question.

It is possible to use foam sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. as a water-resistive barrierSometimes also called the weather-resistive barrier, this layer of any wall assembly is the material interior to the wall cladding that forms a secondary drainage plane for liquid water that makes it past the cladding. This layer can be building paper, housewrap, or even a fluid-applied material. (WRB). However, those who choose this route should know:

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  • Some brands of foam have been approved for use as a WRB, while others have not.
  • Even if you choose a code-approved foam, you can run afoul of your local building inspector if you don't follow strict fastening and seam-sealing details.
  • How To Combine Board and Batten Siding With Exterior Rigid Foam?

    Posted on September 1, 2010 by Scott Gibson in Q&A Spotlight

    Claire Remsberg, an architect in the Rocky Mountain region, is working on a house where the main goals are to limit thermal bridgingHeat flow that occurs across more conductive components in an otherwise well-insulated material, resulting in disproportionately significant heat loss. For example, steel studs in an insulated wall dramatically reduce the overall energy performance of the wall, because of thermal bridging through the steel. through the 2x6 wood frame and to beef up wall R-values. Plans call for vertical wood siding over a layer of rigid foam insulation.

    If that sounds more or less straightforward, the details are not. The contractor has limited experience working with rigid exterior insulation, Remsberg writes, and has concerns that installing siding directly over the foam may not be a great idea.

    Saving Water by Conserving Energy

    Posted on August 31, 2010 by Alex Wilson in Energy Solutions

    Last week we examined the amount of energy it takes to transport and treat water — and how we can conserve energy by using less water. This week, we’ll look at the inverse of that: how much water it takes to produce energy and how our energy conservation efforts reduce water use.

    The water intensity of energy

    Can You Heat a House with Air Ducts in a Concrete Floor?

    Posted on August 30, 2010 by Scott Gibson in Q&A Spotlight

    Concrete floors with high thermal massHeavy, high-heat-capacity material that can absorb and store a significant amount of heat; used in passive solar heating to keep the house warm at night. are often at the heart of passive solar designs. The density of concrete helps it store thermal energy and helps to reduce uncomfortable swings in indoor temperatures.

    Slabs collect some heat from the sun through south-facing windows, often supplemented by radiant-floor heating systems that use a network of embedded plastic tubing to circulate hot water.

    LEED-H Clarifications Raise More Questions Than They Answer

    Posted on August 29, 2010 by Carl Seville, GBA Advisor in Green Building Curmudgeon

    In a post from last summer on LEED for Homes, I mused on the ineffectiveness and confusion surrounding the required Durability Planning process, the preparation of a project-specific Durability Checklist, and third-party inspection of this work.

    The History Of Insulation

    Posted on August 27, 2010 by John Straube in Building Science

    In our last episode, Dr. John talked about How Heat Moves Through Homes and why radiant barriers work better in outer space than on earth.

    In this episode, Dr. John talks about the history of insulation, how different materials work, and where they make sense.

    TRANSCRIPT
    The history of insulation comes about because of the history of structural engineering. Now, I’m a recovering structural engineer, which is probably why I like to think of it that way.

    Window Reflections Can Melt Vinyl Siding

    Posted on August 27, 2010 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

    UPDATED September 3, 2013

    In almost every corner of the U.S., reports are increasing of vinylCommon term for polyvinyl chloride (PVC). In chemistry, vinyl refers to a carbon-and-hydrogen group (H2C=CH–) that attaches to another functional group, such as chlorine (vinyl chloride) or acetate (vinyl acetate). siding that has been melted by sunlight bouncing off nearby windows. This melted-siding pandemic makes vinyl manufacturers very nervous — so nervous that the topic is rarely discussed.

    Green From the Start Redux, or Trying to Build Green in a Historic District

    Posted on August 26, 2010 by Carl Seville, GBA Advisor in Green Building Curmudgeon

    In case you haven’t read my earlier posts about my aborted attempt to build myself a house, Green From the Start Home Edition, Green From the Start Home Edition, Volume 2, and the dismal ending to the first half my saga, What We Have Here Is a F

    Is America Ready for a Home Urinal?

    Posted on August 24, 2010 by Alex Wilson in Water Efficiency

    There are some significant advantages to urinals when it comes to bathroom maintenance (I won't go into the messy details of splashing that happens when males stand and urinate into a toilet). With ultra-efficient urinals (often called one-pint urinals) and waterless urinals, there are also very significant water savings that are achieved.

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