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15 Answers

Insulation in floor joists of an encapsulated crawlspace?

Hi! We're currently in the planning/permitting phase of building an high performance home in the Southeast. We've employed a green building specialist to help model our house to find the proposed hers rating and put into effect all the awesome things we've been reading about on gba. But our contractor (general, traditional) is giving us some push back about one of his recommendations. The green building specialist recommended we put rock wool insulation in the floor joists above our encapsulated crawlspace based on his computer modeling of our home.

In Energy efficiency and durability | Asked By Megan Wood | Jul 11 15
6 Answers

On concrete walls that are fully exposed (above grade) for a new residence, should there be an air space?

We are constructing a new dwelling in Climate Zone 4. Site constraint will have one side of the house built in to a hillside, so the exterior wall is retaining, and will be poured concrete. The owner likes the modernist look of exterior concrete walls, so we are planning to use poured concrete walls on the other elevations as well. I am planning on dampproofing the exterior of the retaining sections of wall, and framing the interior with 2x6 studding and insulation, like a finished basement wall condition.

In GBA Pro help | Asked By Jeffrey Lees | Jul 21 15
4 Answers

How to ensure energy efficiency/green building with a GC who is not experienced in energy/green techniques?

I am planning to build a green, energy efficient modular house in CT (shooting for around 45 HERS). The modular company bills itself as green/efficiency-savvy, but its local rep who will serve as the GC is not energy-savvy (and does not claim to be). The GC is open to hiring subs that we recommend and working with others to achieve our goals.

Apart from relying on the modular company, how can I ensure that the GC does what needs to be done and does it properly? Would I hire an energy consultant or an architect who would serve as a consultant? Thanks in advance.

In Energy efficiency and durability | Asked By Adam Silverman | Jul 20 15
1 Answer

What type of insulation to use?

We have just started a remodel on an old farmhouse in the Zone 6 region. The old 1 1/2 story farmhouse used 2X4 roof and wall framing with ship lap on both sides of the walls and on the top of the roof. The walls have blown in cellulose and the attic space has blown in fiberglass. The new part will be 2X6 construction and we are matching the roof lines but using 2X8's for the rafters with the ceiling leveling off and 2X8 tie rafters.

In GBA Pro help | Asked By John Berlage | Jul 22 15
1 Answer

Spray foam in ground

I don't know if anyone has an opinion about this but I thought I'd post it here. My wife and I had a new home built that was completed in April...that is...completed until 2 days before we move in there was a major fire that was written off by our insurance company as a total loss. This home was spray foamed (closed cell) throughout and had Superior Walls with the blue Dow insulation. The fire ran under the trusses and destroyed the inside but the exterior walls and foam are intact.

In General questions | Asked By Mel Tillyard | Jul 21 15
3 Answers

PolyIso inside 1949 brick veneer walls?

This 1949 Cape Cod style home is in SW lower Michigan just a short distance south of the zone 5A-6A line. My goal is to reach toward the 6A standards, esp. with the long, very sustained cold we had last winter.

The walls are very porous: brick veneer (but for upstairs, clapboard dormer), Insulite Bildrite Sheathing, and what appears to be mineral wool insulation in the wall cavities. The interior walls are covered with a smaller (2' x 4' ish--judging by the seams that are showing) type of gypsum panel that was apparently used at that time.

This is a modestly sized house

In Energy efficiency and durability | Asked By Grant Vandermeulen | Jul 21 15
1 Answer

100+ year old brick basement... how to weather/waterproof?

I live in a 1890s brick row home in Chicago (5A climate zone). When we bought the house 5 years ago, the previous owner had finished the basement. Over the course of the past few years, it became evident that there was moisture building up behind the drywall, as parts began to ripple and even crumble near the baseboards. This spring, I removed the bottom 2 feet of dry wall around the perimeter, which exposed the brick foundation, and standard 2x4 studs that had been treated with some sort of mold resistant compound on the bottom 12" (and, as guessed, some mostly drywall!).

In General questions | Asked By Amanda Scaletta | Jul 21 15
1 Answer

Sealing & insulation of rim joints (brick house)

Hi. I have a 1951 cape which is mostly brick/block except for this room in question, built in 1980, which is brick veneer with a wood frame. There is a bedroom above it and a sided wood dormer begins at the top of this room on the side with the fireplace, and the other side w/ the bay window is the eave of the roof. I am working on replacing the ceiling and noticed that the rim joists only have fiberglass insulation packed in,which I'm sure was typical for the time.

In General questions | Asked By G S | Jul 21 15
7 Answers

Controlling humidity levels in unvented attic space

We have three attic spaces that are sealed with open cell spray foam. There are HVAC systems in all three spaces. We live in Herndon, VA. I checked temperature and humidity levels the other day and found the attic spaces to be running about the same temperature ( 76 degrees) but 10% to 12% higher in humidity (54% first floor vs. 65% attic space). Is there a need for us to be concerned about this differential and if so how would we reduce the attic space moisture levels? We do use the attic spaces for storage. Thank you.

In Energy efficiency and durability | Asked By Woody McMahon | Jul 8 15
11 Answers

Foam in the middle - Will it stand the test of time?

I've done a lot of looking/reading and I must not be searching with the right key words. I can't find anyone else that has built this style of wall/roof (layer of foam in the middle) but I'm sure someone has.

In Energy efficiency and durability | Asked By Carl U | Jul 17 15
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