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3 Answers

How to insulate parallel chord roof trusses?


In Energy efficiency and durability | Asked By Robert Butler | Sep 12 15
1 Answer

Does roof color matter much over a well insulated vented attic?

Here's a roof assembly I'm considering, from ceiling to roof: Gypsum, furring (space for overhead wiring), zip sheathing (air barrier), vapor barrier, energy trusses filled with R-65 cellulose, osb sheathing, roofing felt, batten grid, and through fastened steel roofing. It would have ridge and soffit vents. With a roof like this, with two ventilation layers and thick insulation, does the roof color matter much? I'm looking at a snowy mild heating climate (Rochester, NY area.)

In Energy efficiency and durability | Asked By John Ranson | Sep 14 15
4 Answers

Vapor barrier in showers with exterior foam

IF anybody has any advice on what to do with a vapor barrier behind hardi backer for shower tile walls that would be helpful. I've got a few inches of exterior ISO and don't want to sandwich the walls with vapor barriers. Thanks

In General questions | Asked By Stan Smith | Sep 14 15
10 Answers

How much moisture can a crawlspace/air gap introduce?

This house has 400 sq/ft of basement and 300 sq/ft of crawlspace, and despite my best efforts i had to install a dehumidifier. It needs emptying 2-3 times a day (30 pint/day model) meaning its pulling 20-30 pints a day. The crawlspace is not encapsulated (and shallow and hard to traverse) and the energy audit showed almost 15ACH50, much of it coming from the crawlspace, i have been in there a few times but could not locate the air leaks but i could not access all of it.

In Energy efficiency and durability | Asked By Alan B | Sep 9 15
13 Answers

Basement walls

I am building a ranch home and most of the basement (2800sqft) will be finished as living space. The builder has the waterproofing membrane spray on the outside of the basement, the plan calls for 2x6 with r21 insulation batts, and a certainteed membrain. There are drain tiles on the interior of the basement walls and the exterior. There will also be 10 mill poly underneath the basement slab when it will be poured.

In GBA Pro help | Asked By D L | Sep 9 15
6 Answers

Very good traditional plus energy architect?

We are planning to build a new house. Our two primary requirements are that it be very traditional and energy efficient sustainable quality construction. We've found a few architects who are good on one but so far none who are good on both.

This will be fairly high-end with a $2m - $3m budget for the structure so we're looking for someone who is well versed in this level of detail and aesthetic. Style is perhaps best described as 18th century upper east coast. We are in the 'cold' climate zone according to BSC and Energy Vanguard.

In General questions | Asked By Jason Fox | Sep 12 15
3 Answers

Optimal insulation for slab on grade

I've seen a number of recommendations for insulation for slabs, but few seem to differentiate between basement slabs, and slabs on grade. (Or for that matter, between slabs in a storage basement, versus slabs that people walk on.) For instance, Building Science in their BA-1005 report has a single column for sub-slab insulation on page 10.

In Energy efficiency and durability | Asked By John Ranson | Sep 12 15
7 Answers

Questions on sealing rim joists (and a few other items)

I have fiberglass insulation acting as a seal between my foundation and sill plate. Can air still get through there?

The foundation on the front of the house is below grade, and the rim joists are well above the foundation. Is sealing here as important as the if the rim joists and sill plate are directly on the foundation?

In General questions | Asked By Forum User | Sep 12 15
17 Answers

How to build a gabled roof on a rigid insulation roof?

Hello to all at this forum. Back in 2013 I posted on my garage build here....


Since a few months now I had started doing some work on my home to increase the insulation value.

I am including a photo of how it is today just before we add the roof sheathing, but I am sort of stuck on how to include a gable roof on each end of the house.

In Green building techniques | Asked By Leon Stepanian | Aug 17 15
4 Answers

How to avoid trapping moisture in a wall with interior and exterior gypsum?

I live in a wildfire zone in California and am building a shed with metal siding. With metal siding, FEMA's recommendation and local county codes require a thermal break between the wood framing and external siding. The details are shown here:

Page 36, Figure 2

My concern with this setup is moisture being trapped in the wall. My layers from inside-out will look like this:

interior gypsum -> framing/insulation -> plywood sheathing -> exterior gypsum -> wrb -> metal siding

In Energy efficiency and durability | Asked By Peter Hsu | Sep 11 15
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