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43 Answers

Air sealing and the point of diminishing returns

I'm curious at what point does it no longer make sense to spend more time/money on tightening up a house. We had our house blower door tested unfortunately after construction was completed. The house is closed cell spray foam walls and ceiling.

I was shocked that the first test was 3.2 ACH50. The test along with thermal imaging allowed us to locate some major problem areas that we addressed, most of which were behind timbers in corners that did not get sealed well. (House is a timberframe hybrid).

In Energy efficiency and durability | Asked By Jeremy Kovac | Mar 10 16
8 Answers

Is it OK to run the main water supply line up into attic to be supplied throughout the home?

30 year or more home, built on a slab, and water lines are being damaged and lines are breaking. All lines are coming from under the slab in each part of the home where water is needed.

I now have a water leak that could be further under the slab and not reachable. I recently repaired a pipe at the back wall of my home where as l had to dig under the slab and it was reachable. Now at this time this leak is not and cannot be seen. What must I do?

In General questions | Asked By Cedric Stephens | Apr 12 16
6 Answers

Virginia: High wind and rain lead to cathedral ceiling stains

I know, can lights are bad. Our builder was supposed to know better. We have 13! Ceiling stains occur even when we are away for a month or more. Obvious mistakes are ridge vents that allow rain to blow in, ridge only partly vented.

In GBA Pro help | Asked By John Haskill | Apr 9 16
4 Answers

Retrofit vented attic to... unvented?

Quick question for the board members... Currently in the prep phase for a second story addition to one part of our house, that will entail splicing into the existing roof for roof/wall flashing as well as some structural improvements to a few rafters..

The current roof structure is 2x4 rafters, sitting on the wall top plate with birds mouth cut... so... Effectively, 1-2" of insulation if i'm lucky.

In Energy efficiency and durability | Asked By John O'Brien | Apr 10 16
4 Answers

What are long-term maintenance costs for ductless minisplits?

I'm not concerned about annual clean-the-filters type maintenance, but more about "What if a power surge blows a mother board?" type issues. My sister has had that happen twice, although it may be partially due to a poorly grounded electrical system. Other issues might be refrigerant leak or motor failure.

Does anyone have the kind of long-term, multi-installation experience needed to address this type of issue?

In Mechanicals | Asked By Robert Fankhauser | Apr 11 16
2 Answers

Radiant heat in an old house remodel

I am looking at potential radiant options for an old farm house. Probably just the first floor at this time. My concern is we want to keep the original wood floors- so that means that we are looking at 1" plank subfloor and a <1" finished t & g flooring. The house is about 70-80yrs old. Is this too much/thick for practical radiant heating? I would imagine it would require more/higher water temps and be less responsive?

In Mechanicals | Asked By Steven Mikel | Apr 12 16
39 Answers

Earth tube ducted through thermal mass concrete wall

OK, here's the basic idea. I would like to use an earthtube system to bring fresh air into a very tightly sealed home.

I'm also designing the home with a "solar stairwell", a stairwell that's exposed to the sun with big windows, with the back wall of the stairwell being made of dark-colored cast concrete.

During cold months, the concrete wall acts as thermal mass, gathering heat during the day and shedding it during the night. Exterior louvered shades above the big windows would keep this wall from getting direct sunlight during the summer.

In Green building techniques | Asked By Daniel McKinney | Apr 4 16
12 Answers

Tilt turn windows with good visible transmittance

Can anyone recommend manufacturers of quality, energy efficient, tilt turn windows with good visible transmittance. If I'm going to put a hole in my wall for a window, I don't want to fill it with a thick frame and dim glass. The NFRC website lists 64 manufacturers of tilt-turn windows, and I don't know where to start. I'm designing for zone 5. I am cost sensitive, but willing to pay for quality.


In Green products and materials | Asked By John Ranson | Sep 24 15
5 Answers

Venting a flat roof properly

I have an existing house with a flat roof with an an addition that has a shed roof on one side that blocks the vents on one side. The shed roof addition stands 8ft above the flat roof. The original construction had fascia vents on both sides of the roof, but when they built the addition they blocked one side. I am renovating the addition portion of the house and plan to use closed cell on the walls and ceiling.

In Energy efficiency and durability | Asked By James DeSalvo | Apr 10 16
1 Answer

Insulating a sloped open space

How would one place cellulose in a large 2' tall sloped (4:12) under roof space with a smooth sloped floor and ceiling and no internal framing? Assume that ventilation is taken care of elsewhere. My biggest concern is keeping the insulation where it belongs.


In Green building techniques | Asked By John Ranson | Apr 9 16
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