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1 Answer

Sloped ceiling insulation

I have a story and a half home that we are remodeling. We also added a garage with bonus rooms above. We are climate zone 6 in Gillette WY. We taped all OSB seams, are adding 2” of rockboard insulation with 3/4 rain screen and Lp smartside lap siding to the exterior and used ThermalBuck to fur out our windows. We will also be using Ecoseal Plus to air seal interior framing.

To the point:

In Energy efficiency and durability | Asked By user-7005570 | Apr 22 18
8 Answers

Slab on grade house and garage : can I pour the floors once the shell is up?

I currently have the footings frost walls (4'), and the sandy base filled in and tamped for the slab. The house is roughly 50'X30', 2 storey, and the floor joists can technically span 30' (24" deep trusses), but the plan has a "supporting" wall roughly in the middle of the width to keep the floor span at 15-17'.

The garage is 30'X40', with no supporting walls (wide open).

In GBA Pro help | Asked By Mai Tai | Apr 21 18
10 Answers

Small addition with helical pile foundation in Toronto Canada


I am an architect in Toronto. My client is a contractor who wants to build a small one storey addition using helical pile foundation instead of continuous foundation to save on cost.

The finished floor is raised above the grade by about 21".

My questions:

-Can I use chicken wire to support the fibreglass insulation in the floor joists as it would be difficult to finish the underside of the floor with plywood I think
-Do I need a air-barrier like tyvek under the fibreglass insulation

In Green building techniques | Asked By Lowell Lo | Apr 22 18
6 Answers

Heat runs to unfinished basement? Pacific NW area

I realize the basement is considered part of the conditioned space, but I was a little startled at an HVAC guy proposing to cut heat runs into the basement (which we do not plan ever to finish). It's a 1901 basement with concrete walls to ground height and wood joists above that. Previous owners had put fiberglass insulation in the joists, which was a really bad idea as one can see from old water stains. That's long gone, but when we first lived in the house we used to get water coming up through the floor drain during storms (no leaks through the walls that I am aware of).

In Energy efficiency and durability | Asked By Irene3 | Apr 20 18
8 Answers

Mini-split energy usage

I thought I would offer some energy usage I had this winter with my Mitsubishi mini-split. Some info

Units: Mitsubishi MSZ-FH12NA H2i and MZ-FH15NA H2i heat pumps.
Location: Just North of NYC
99% outdoor temp - 12 degrees F
Heat load - 26,000 BTU

Month Degree Days KWh KWh/Degree day
Apr 12, 2018 824 997 1.20
Mar 14, 2018 817 978 1.19
Feb 12, 2018 1035 1450 1.40
Jan 11, 2018 1248 1773 1.42
Dec 11, 2017 751 870 1.15

In Energy efficiency and durability | Asked By WPmichael | Apr 20 18
1 Answer

Is this a vapor-permeable air barrier?

1960's home... wall construction is as shown, with face brick on the back side. Silver faced material is thin (maybe 1/8" thick).

I did not notice originally, but in good light, once can see what may be perforations in the surface.

Does anyone recognize if this is a vapor permeable sheathing material?

In General questions | Asked By Rossn1 | Apr 21 18
11 Answers

Furr-UP instead of furr-down to include ducts in the envelope?

Hi all,

I'm building a new home in south Louisiana and I've been lurking here for a few week soaking up some energy efficiency building techniques.

One of the biggest points I see on here is to include the HVAC system in the insulation envelope. But, that isn't standard practice in Louisiana for new construction ( as in, NO ONE does it in my area). I get the deer-in-the headlights when I even mention a closet unit with ducts installed in furr downs. This also goes for Framers and Home Designers

In Mechanicals | Asked By Jiggernaut | Apr 18 18
3 Answers

Basic vapor barriers question (kneewalls)

I've been reading GBA on air barriers.

Basic building science question that I'm hoping you can help me understand:

From a vapor/moisture perspective (ie, ignoring the 2x thermal barrier), what are risks to hanging polyiso on kneewall AND on roofline in a kneewall space? How much airflow is needed to reduce those risks of 2x vapor barrier?


In General questions | Asked By Emerson | Apr 20 18
5 Answers

Foundation Waterproofing & Insulation Treatment

My new home design has an 8' basement and an attached garage with a 4' foundation. Is the garage foundation poured at the same time as the house or separately? On the basement foundation walls I'm planning to use spray-on waterproofing, board insulation, and a dimple mat. I'm not sure how to treat the vertical edge condition where those materials would start/stop. I used Sketchup to help myself visualize what's happening. Do basement exterior materials wrap under the garage footings and continue along the basement under the garage slab?

In Green building techniques | Asked By Bryanw511 | Apr 20 18
30 Answers

Are "Energy Nerds" in agreement on this?

"PV's are cheap enough now to remove the need to super insulated houses"

In General questions | Asked By tech1234 | Apr 19 18
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