Q&A Spotlight

Fixing a Leaky Log Home

Posted on March 24, 2014 by Scott Gibson

Early settlers who felled their own trees to build log homes were probably so grateful to be out of the weather they didn't worry about air leaks or cold walls. But when your heating bills are $500 a month, it's a different story altogether.

That's the situation facing ADK Homeowner, as he explains in a Q&A post at Green Building Advisor.

HVAC for a ‘Pretty Good House’

Posted on March 10, 2014 by Scott Gibson

Matt Mesa is looking ahead to retirement in a new, one-level house in Hood River, Oregon. It's going to be a Pretty Good House, a phrase coined to describe a well-insulated house of an appropriate size.

Flash and Batt in the Roof

Posted on February 24, 2014 by Scott Gibson

"Flash and batt" is an insulation technique that combines the air-sealing superiority of spray foam insulation with the cost benefits of fiberglass batts. An inch or two of polyurethane foam seals the cavity and the batt insulationInsulation, usually of fiberglass or mineral wool and often faced with paper, typically installed between studs in walls and between joists in ceiling cavities. Correct installation is crucial to performance. adds R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. without costing an arm and a leg.

That's roughly the plan Dave Frank is considering for the roof of a house — presumably his own house — in Climate Zone 5. But his plan contains a twist: He wants to spray the underside of the roof deck with foam and install the batts between the joists at ceiling level.

The Big Allure of Cheap PV

Posted on February 10, 2014 by Scott Gibson

Until now, Patrick McCombe has believed that improvements to the envelope of his home should come before an investment in photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. panels. Now he's weighing a deal that seems too good to pass up.

McCombe lives in Connecticut (he's an associate editor at Fine Homebuilding magazine) and he recently attended an informational meeting sponsored by an organization working to lower the cost of PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow.. Panels could be purchased or leased, but the bottom line was that with federal and state incentives, McCombe could buy a 10-kilowatt array for $15,000.

Singing the Ice Dam Blues

Posted on January 27, 2014 by Scott Gibson

Winter is the season of icicles and ice dams, at least on houses whose roofs are poorly insulated and air-sealed.

Or, in the case of a nature center in Wisconsin, not insulated at all. Walt Ott is inquiring about the best way to fix a building with a completely uninsulated cathedral ceiling.

Why Is This Wood Stove Misbehaving?

Posted on January 13, 2014 by Scott Gibson

Clark Agnew should be the envy of his neighborhood. He has a tight house, a high-efficiency wood stove with its own fresh-air intake, and access to free firewood. A heat recovery ventilator (HRV(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. ) keeps indoor air healthy. What's not to like?

But, as he writes in a Q&A post at Green Building Advisor, the situation is far from ideal.

"I have run the stove about 6 or 7 times since we moved in," Agnew writes. "Three of those times it has backdrafted."

Installing Windows the Right Way

Posted on December 30, 2013 by Scott Gibson

Brian Beaulieu would seem to be well on his way to enjoying a high-performance house in southern Maine. The double-stud walls are 10 1/2 inches thick and insulated with mineral wool. The exterior air barrierBuilding assembly components that work as a system to restrict air flow through the building envelope. Air barriers may or may not act as a vapor barrier. The air barrier can be on the exterior, the interior of the assembly, or both. is the taped Zipwall system, backed up with airtight drywall on the interior for a second line of defense against air leakage.

Beaulieu has invested in top-quality tripled-glazed Intus windows suitable for PassivhausA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. designs. And it's here that Beaulieu has run into a problem.

Why Is This Sheathing Moldy?

Posted on December 16, 2013 by Scott Gibson

Brian Lent has discovered something in his walls that no homeowner wants to see: mold.

Preparing a ground-floor room for drywall, Lent pulls some fiberglass batt insulationInsulation, usually of fiberglass or mineral wool and often faced with paper, typically installed between studs in walls and between joists in ceiling cavities. Correct installation is crucial to performance. from a 2x6 stud cavity and notices the back side of the OSB 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. is damp. A moisture meter reveals that in 80% of the bay, the moisture content is 66% or higher. Moisture and mold are heaviest at the bottom of each bay.

Insulating the Roof of a Bonus Room

Posted on December 2, 2013 by Scott Gibson

Andrew K has a project that should ring a bell with lots of homeowners: What's the best way of insulating a room over the garage so it becomes useful, conditioned spaceInsulated, air-sealed part of a building that is actively heated and/or cooled for occupant comfort. ?

Andrew lives in Massachusetts, in Climate Zone 5A, and would like to turn the space, what real estate agents used to call a "bonus room," into an office. The roof is framed with 2x8 rafters and already has both soffit and ridge vents, but no insulation whatsoever.

One Minisplit or Two?

Posted on November 18, 2013 by Scott Gibson

Christopher Vernott is an architect at work on his own home — a tight, well-insulated house in southeastern Connecticut — and the time has come to rough-in the heating and cooling system.

Because of the double-stud wallConstruction system in which two layers of studs are used to provide a thicker-than-normal wall system so that a lot of insulation can be installed; the two walls are often separated by several inches to reduce thermal bridging through the studs and to provide additional space for insulation. construction, triple-glazed windows, and careful air-sealing, his heating and cooling loads are low, he writes in a Q&A post at Green Building Advisor.

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