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1 Answer
Minimizing roof penetrations

Are air admittance valves on plumbing vent stacks an acceptable method of reducing roof penetrations in an attempt to minimize energy loss?

In Energy efficiency and durability | Asked By NelsonL | Jun 1 10
4 Answers
Retrofit insulation in attic slanted roof section with no soffit vents

I have an 1850s 1 and 1/2 story New England farm house. The upstairs bedrooms all have a partially slanted ceiling that is uninsulated. There are no soffit vents and I want to just fill the whole slanted part with insulation. Will that be a problem? Also I did lay in loose cellulose insulation on the flat part of the attic on top of plastic sheeting. Was that wrong to put the plastic down first?

In Energy efficiency and durability | Asked By Ellen Mitchell | May 31 10
4 Answers
Insulation over lath?

How should I address insulating inside rooms over the old lath and blown-in insulation already there? Should I install rigid foam over the lath? And if so, how thick? Or should I rip out the lath and old blown-in insulation, which is very tight, and start fresh?

In Energy efficiency and durability | Asked By Deborah Black | May 30 10
2 Answers
Ductless minisplit vs ducted split AC systems for whole-house application

I've read about a builder in NC that uses ductless minisplits in a whole-house new construction application. What are your thoughts and commentary about such an application?

To run refrigerant tubing vs. a potentially leaky duct even in the conditioned space would seem to be preferable. Not to mention the zoning advantages and conditioning occupied space vs conditioning unoccupied rooms in a non zoned split a/c or h/p system.

In Mechanicals | Asked By Norman Anderson | May 30 10
10 Answers
What is a capillary break between the footing and foundation wall?

Your details show a caplillary break between the footing and foundation walls. What is it? Is it continuous?

In GBA Pro help | Asked By Arthur Ratner, AIA | Jun 23 09
2 Answers
Old house retrofit using Demilec foam in wall and polyiso board OK?

I live in the Western Upper Peninsula of Michigan in a 100 year old house. I have taken the inside down to the studs. I have removed all exterior wood siding. Western exposure was taken completely down to the studs. Plywood sheathing installed, All other exposures kept 1 by sheathing boards, I have covered exterior with 1 inch polyiso board with fiber cover (warm wall).

In Energy efficiency and durability | Asked By john | May 28 10
19 Answers
Wind bracing when using XPS

I would like to build a workshop using 2x4 studs on 16" centers. I can get 1 1/2" XPS at half its cost , enough to do my exterior walls. I want to create a thermal break from the studs, but I am concerned about wind bracing my walls, because of the 1 1/2" between the sheathing and the studs.

Would there be any advantage to using the XPS on the interior, covered with 1/2" drywall? The wall system would be from inside to outside: drywall, XPS, 2x4 studs, batt insulation, sheathing, Tyvek, 3/4" battons, then wood siding. Would this work?

In GBA Pro help | Asked By mike maclean | May 26 10
2 Answers
Why air return in a home?

What problems could result without air return?

In General questions | Asked By larry | May 27 10
7 Answers
What are non-toxic methods for treating or encasing cedar fence posts to extend their useful life?

Alternatively, is there a wood more durable than cedar that might be available in Vermont (e.g., black locust)?

We are about to re-build a backyard fence that will run near an organic garden. We'd like to find an alternative to pressure-treated fence posts (where chemicals seep into the soil) or untreated cedar posts that rot in the ground.

In Green building techniques | Asked By Bonnie | Oct 4 09
4 Answers
Where are the energy-efficient clothes dryers?

I cannot find any information or recommendations on efficient clothes dryers. Does anyone have a good source?

In Green products and materials | Asked By Robert Dynan | May 26 10
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