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9 Answers

Helping my insulation contractor make the right decisions. :)


Good insulation contractors around here are hard to find. A lot of people are doing the work without understanding many of the techniques shared on this site and others. I talked to the person I am considering for my new house and I think I could use your help in educating him a little.:)

1) Radiant barrier in attic

In Energy efficiency and durability | Asked By Norman Bunn | Nov 17 17
8 Answers

Flashing Bottom of Window flange?

I've noticed that a lot of builders will omit taping over the bottom flange of a window once it has been installed. Sides are taped/flashed and the top flanged covered by WRB flap. Yet, bottom flange is left exposed.

I presume this is to allow water to drain from the assembly. But is this really necessary- especially if weep holes are left uncovered? Will this result in air leakage at the bottom of window?

In Energy efficiency and durability | Asked By Rick Evans | Nov 16 17
17 Answers

Residential frost-protected shallow foundation in central Mass.

We are planning to provide a monolithic pour frost-protected shallow foundation (FPSF) for a single story 1300 sq ft 2 bedroom home in central MA. Air Freezing Index is 2000. I have read through many different case studies, research papers, codes, etc and there is a bit of conflicting and locale-specific info so I am looking to see whether I understand what is required here. I am a newbie owner-builder. Any constructive criticism would be appreciated, but I don't want to foment any religious wars.

In Building Code Questions | Asked By Kenneth Gartner | Sep 2 16
4 Answers

How to insulate rim joist that doesn't breathe on the exterior side?

The home was built is 2012 we are in Zone 5b just north of Indianapolis. We are the original owners and have pics during construction phase (unfortunately they were not custom builders and would not let us help with design details. e.g. we couldn't get them to insulate exterior basement walls and below the slab with rigid foam- which is now MADDENING).We are about to finish the unfinished basement. What is the correct way to insulate a rim joist on a modern house?

In Green building techniques | Asked By user-6955054 | Nov 16 17
3 Answers

Which gas furnaces are most efficient in their use of electricity?

I am about to replace a 13 year old 120,000BTU furnace with a much smaller unit that will be less noisy.

I understand that the fans of these units are a significant power draw. The state of MA will give the same rebate to all 95%AFUE furnaces. Is there a difference, where some brands of 95% AFUE furnace will actually use a lot less power?

FYI my furnace is in the attic so I will end up putting in a horizontal downflow unit.

In Energy efficiency and durability | Asked By rich cowen | Nov 16 17
7 Answers

Grounding a Steel Deck Frame

I'm building a weekend cabin designed along the lines of a fire lookout tower. As I am in an wooded area with high potential for wildfires, I am trying to use materials which minimize fire risk. The building footprint is a 22' square and will be constructed using Faswall blocks covered with steel siding and a steel roof. The upper level will have a wraparound "catwalk"-style deck about 15' above ground level. The deck frame will be constructed of hollow structural steel supported by braces anchored to the building walls and the actual decking while probably be a composite decking material.

In General questions | Asked By David Williams | Nov 12 17
1 Answer

Poor Man's Thermomass

The previous conversation got off on a tangent about material costs and PWF... There was not much uptake on my "Poor Man's Thermomass" idea: http://www.greenbuildingadvisor.com/sites/default/files/poormansthermoma...

Since drawing that detail, I have thought about replacing the EPS with rockwool, and have done some research on what the backerboard could be. I understand it can't be Hardibacker or Durock. Perhaps there is another subgrade cementitous board which would be applicable?

In Green building techniques | Asked By Ethan T ; Climate Zone 5A ; ~6000HDD | Nov 15 17
19 Answers

Marine Zone 4 — Wall insulation — addition

Zone: Marine 4
Location: Seattle, WA
House Built: 1915
Square footage: 900 ft2 single story with 900 ft2 finished basement.
Wall height over basement: 12 ft
Current siding: Cedar, Paint in poor condition.
Insulation: not much, some fiberglass bat stuffed in nooks and crannies as they opened walls in the past. And dirty so there is plenty of air gaps.

GOAL: Comfort

In Plans Review | Asked By User-6933356 | Oct 11 17
2 Answers

Should I use a poly-type Membrain sheet or vapor retarder paint for ceiling?

I'm at a crossroads with how to deal with the ceiling vapor retarder in my new construction home in climate zone 5.

I'm prepping for drywall, and am wondering if I should apply Certainteed Membrain vapor barrier to the underside of the studs on the ceiling, and then just have the ceiling drywall screw attached...


Should I have the ceiling drywall glued and screwed and use vapor retarder paint instead.

I plan on blowing R60 cellulose in the attic when done, and am concerned about it's weight on the drywall.

In Green building techniques | Asked By Adam Peterson | Nov 14 17
4 Answers

Why caulk between studs, etc?

I understand that a small amount of air can pass through the gap between two or more side-by-side framing members, but so what? Then that air hits the drywall, which is an air barrier. In the middle of a stud bay, that same air is passing through fiberglass batt insulation (not an air barrier) and hitting the drywall. What's the difference? For that matter, why caulk the drywall to the top plate? Isn't the intersection of the wall and ceiling drywall taped and mudded? Isn't that an air barrier?

In GBA Pro help | Asked By JeffSch1 | Nov 8 17
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