foam sheathing

Choosing the Right Wall Assembly

Posted on March 06,2015 by ScottG in cold OSB

Michael Roland is designing a new house and trying to choose the right wall assembly. It’s down to a choice between a double-stud wall filled with fluffy insulation, or a single wall wrapped in a layer of rigid foam insulation.

Window Installation Tips for a Deep Energy Retrofit

Posted on March 06,2015 by JoelSchuman in deep energy retrofit

In May 2011 we began a deep energy retrofit of our old, cold, drafty house in Saugerties, New York. Because the house was poorly and cheaply built in the 1840s (apparently from scraps and salvage), we were leery of opening up the walls from the outside, lest we find that the clapboard siding and incomplete sheathing were all that had kept the house from collapsing.

Exterior Insulation Is Like A Sweater For Your House

Posted on March 06,2015 by user-1048334 in EPS

There are many construction and insulation approaches which allow a builder to create walls and ceilings with high R-values and low levels of air leakage, creating a much better envelope than is achieved with standard framing methods. Structural insulated panels (SIPs), insulated concrete forms (ICFs), double-stud walls, and advanced framing can all produce more energy-efficient buildings than the ol' stick-built number. The one thing they can’t do is to improve the efficiency of an existing house.

Is There Such a Thing as a Perfect Building Envelope?

Posted on March 06,2015 by ScottG in exterior foam

Is there such a thing as a perfect building envelope? One that could be mass-produced from readily available materials, and be appropriate for 90% of all new homes? Andrew Homoly thinks he’s found one, as he explains in this Q&A post at GreenBuildingAdvisor.

How to Install Rigid Foam Sheathing

Posted on March 06,2015 by user-756436 in EPS

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. My conclusion: it’s time to provide a primer on the topic.

Nailing Window Flanges Through Foam

Posted on March 06,2015 by user-756436 in fastening window

Over 30 years ago, when builders first began installing rigid foam wall sheathing, they had to figure out their own methods of fastening flanged windows. In 1982, when I sheathed my house with 1-inch-thick EPS, I installed “picture frames” of 1-inch lumber around each window rough opening. As it turned out, Joe Lstiburek was also building a foam-sheathed house in 1982, but he used a different approach.

Where Does the Housewrap Go?

Posted on March 06,2015 by user-756436 in drainage plane

Let’s say you’re building a house with plywood or OSB sheathing. You plan to install 2 or 4 inches of rigid foam on the exterior of the wall sheathing, followed by vertical rainscreen strapping and siding. Where does the housewrap go? Depending on who you talk to, you get two different answers:

  • It goes between the rigid foam and the vertical strapping, or
  • It goes between the sheathing and the rigid foam.

Fastening Furring Strips to a Foam-Sheathed Wall

Posted on March 06,2015 by user-756436 in foam sheathing

UPDATED March 1, 2012 If you’re building a house with foam sheathing, and your siding is installed over vertical rainscreen strapping installed on top of the foam, how should you attach the strapping? Most builders screw the strapping through the foam into the studs; so far, so good. But what length screws should you use? And how closely should you space the screws?

Calculating the Minimum Thickness of Rigid Foam Sheathing

Posted on March 06,2015 by user-756436 in condensation

UPDATED on August 26, 2014 with new information on flash-and-batt requirements in the 2012 IRC If you plan to install exterior rigid foam on the walls of your house, how thick should the foam be? Although the GBA Web site has addressed this question several times in our Q&A column and various blogs, the question continues to perplex readers. New questions along these lines come our way regularly. The last time I answered the question was at the end of a long, very technical blog. In this blog, I'll cut to the chase.

Are Dew-Point Calculations Really Necessary?

Posted on March 06,2015 by user-756436 in condensation

Most builders understand that condensation can form when warm, moist air encounters a cold surface. Condensation is bad, and builders want to avoid it. There’s a solution, though: According to building scientists, we can prevent condensation problems in walls by determining a wall’s temperature profile and performing a dew-point calculation. This calculation may require the use of a psychrometric chart.

Using Rigid Foam As a Water-Resistive Barrier

Posted on March 06,2015 by user-756436 in foam sheathing

Do foam-sheathed walls also need housewrap? There’s no simple answer to the question. It is possible to use foam sheathing as a water-resistive barrier (WRB). However, those who choose this route should know:

  • 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.

Best Construction Details for Deep-Energy Retrofits

Posted on March 06,2015 by user-756436 in deep energy

A collection of experts working on deep-energy retrofits recently attended a brainstorming session to share design tips and propose topics for further research. The conference, formally titled the “Expert Meeting for Details for Deep Energy Retrofits,” was held in Boston on March 12. The meeting was funded by the Department of Energy’s Building America program and hosted by the Building Science Corporation.

Energy-Efficiency Retrofits: Insulation or Solar Power?

Posted on March 06,2015 by user-756436 in deep energy

For our country to achieve the carbon emission reductions necessary to avoid a planetary catastrophe, many experts contend that almost every house in the country will need to have retrofit work that achieves deep cuts in energy use. There’s a major stumbling block, however: deep energy retrofits are frighteningly expensive —in the range of $80,000 to $250,000 per house. With costs so high, many homeowners are asking: how long is the payback period for a deep-energy retrofit?

Getting Insulation Out of Your Walls and Ceilings

Posted on March 06,2015 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.

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