exterior foam

Two New Exterior Insulation Products for Walls

Posted on January 29,2015 by user-756436 in DuPont

Exterior wall insulation? That usually means rigid foam and furring strips — although occasionally, it means mineral wool insulation and furring strips. But there are other options. Two new products offer builders new ways to keep their wall sheathing warm.

How to Seal Sheathing Boards

Posted on January 29,2015 by ScottG in air-sealing

The use of plywood and OSB sheathing is a fairly recent phenomenon. Before these sheet goods became readily available, builders nailed wood boards to the frame of a house for sheathing, and it is a house with this type of sheathing that Nick Welch is trying to update. His 900-square-foot house in Climate Zone 4C is sheathed with 1x8 boards, apparently over a layer of asphalt felt. There is apparently no insulation in the wall cavities behind the sheathing. His plan of attack is to air-seal the house, then install foil-faced polyisocyanurate insulation over that. The question is how.

Window Installation Tips for a Deep Energy Retrofit

Posted on January 29,2015 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 January 29,2015 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.

A Real Chainsaw Retrofit

Posted on January 29,2015 by user-756436 in Chainsaw retrofit

When workers need to insulate the walls and roof of an existing building with exterior rigid foam, it often makes sense to cut off the roof overhangs first. With the eaves and rakes removed, wrapping the building in rigid foam is a snap. The missing roof overhangs can later be rebuilt by scabbing the necessary framing on the outside of the foam.

Is There Such a Thing as a Perfect Building Envelope?

Posted on January 29,2015 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 Insulate a Wall from the Outside

Posted on January 29,2015 by ScottG in exterior foam

Gregg is renovating his 50-year-old house in Wisconsin and trying to devise the best way of insulating exterior walls from the outside. The house was built conventionally, with 2x4 walls, fiberglass batt insulation, fiberboard sheathing, and hardboard siding. He plans to tear off both siding and sheathing and remove the batt insulation, then apply 3 in. of spray polyurethane foam insulation into the stud bays. The existing kraft paper vapor barrier on the interior side of the wall will stay in place.

Where Does the Housewrap Go?

Posted on January 29,2015 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.

How to Finish Exterior Foundation Insulation

Posted on January 29,2015 by ScottG in exterior foam

Energy gurus and building codes routinely recommend these days that foundation walls be insulated. One way of accomplishing that is by adding a layer of rigid foam insulation on the outside of the foundation. And that's exactly what William Poole is planning to do. Most of the rigid foam insulation will be underground and out of sight. But what do you do with that stretch of exposed insulation above grade?

Are Dew-Point Calculations Really Necessary?

Posted on January 29,2015 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.

Best Construction Details for Deep-Energy Retrofits

Posted on January 29,2015 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 January 29,2015 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?

An Agent of Green Invention in Philly: Row House Demolition

Posted on January 29,2015 by Fretboard in Exolation

Homes adjacent to demolished rowhouses in Philadelphia are left with more exposure to cold and heat. But three local professors collaborated on a solution There are certain efficiencies inherent in rowhouses, not the least of which is that their common sidewalls limit extreme-weather exposure largely to the front and back of each house. Noise sometimes leaks through the walls, but rowhouse living generally is fairly comfortable and energy efficient for city dwellers. Unless, of course, the rowhouse next to yours is razed.

‘Innie’ Windows or ‘Outie’ Windows?

Posted on January 29,2015 by user-756436 in deep energy

Builders in northern states and Canada often specify exterior wall foam for new construction as well as for residing jobs on existing houses. Installing rigid foam on exterior walls reduces thermal bridging through studs and (as long as the foam is thick enough) greatly reduces the chances of condensation in wall cavities. Current trends favor thicker and thicker foam; many cold-climate builders now routinely install 4 or 6 inches of EPS, XPS, or polyiso on exterior walls.

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