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14 Answers

Blower door and HRV question

i just had a blower door test done on our new R-2000 build. The house is almost ready for occupancy. The initial test showed about 1.3 ach @ 50 pa but I was sure it would test far tighter.

After snooping around, I realized that both the interior supply and exhaust diffusers for the HRV were badly hemmorrhaging air. After sealing both the exterior supply and exhaust vents, the ACH dropped to .8 ach. Why is this happening?

In General questions | Asked By erik olofsson | Jun 2 13
1 Answer

I have a home with two stained walls

I have a home with two stained walls. One wall is on a corner to the house. The other is in a angle (upper) near the roof.
I'm sending some pictures so you can see the stain.
I have cleaned it up and it comes back again.

In GBA Pro help | Asked By blanca goertzen | Jun 10 13
3 Answers

Opinions or experience with APEX block?

Searching for wall assembly options, weighing cost, thermal performance, durability and so forth, below and above grade, SIPs, ICF, SCIPs, brought me to APEX block. Cementious mix with EPS type of ICF, the EPS form creates a tubular-type grid of concrete with rebar. Supposedly uses something like 25% less concrete than standard ICF, while claiming R-38, and uses recycled EPS at a lower cost than ICF. Anyone have any opinions/experience with the product?

In Energy efficiency and durability | Asked By Sal Lombardo | Jun 5 13
1 Answer

Propane 'energy pods'

I'm regularly seeing banner ads in my GBA feed for propane 'energy pods', linking to this site: http://buildwithpropane.com. I'd welcome comments from those better-informed than I on the claims made there which rather fly in the face of all I thought I understood about the cost effectiveness and carbon emissions of this energy source.

In Mechanicals | Asked By James Morgan | Jun 9 13
8 Answers

Fun With Fluids

(starting 1:30 minutes into this video)
Thorsten Chlupp mentions a fascinating concept ...Stratification

It seems we can "store" a not-so-dense fluid above a dense fluid....

It's kind of Intuitive that a dense fluid will support a not-so-dense fluid.

What's Not so Intuitive is that the "fluids" might be in very distinct layers.
...separated by "Internal Waves"....

similar to this demonstration

In Energy efficiency and durability | Asked By John Brooks | Jun 8 13
4 Answers

Insulation question

Am currently in the middle of a major remodel on a late 1800's farmhouse in Eastern Washington State. Have discovered a 'insulation system' I've never seen and maybe someone out there has. I am unsure of how to 'add' to it. The wall consists of typical roughcut stud 3 1/2'' thick with 1x8 shiplap on each side. After the outer shiplap, there is a thin 1'' batt. In its encasement is a thin white cotton like substance. Then there is a couple inches or so of air space followed by a very waxy, tough looking paper. Its color of greenish brown.

In Energy efficiency and durability | Asked By Tim Sullivan | Jun 7 13
1 Answer

Vapor retarder, sealing and ventilation - what to do with an old 1960's ranch?


I am an owner builder and I have a humble question related to vapor retarders for the experts, nerds and a like on this forum. I have been reading about vapor retarders, sealing air leaks and ventilation here, building science website and elsewhere for a while and I have talked with the village building inspector about them.

In Building Code Questions | Asked By Heidi Herttuainen | Jun 7 13
1 Answer

I need help with a detail and process to side a home BEFORE the windows arrive from Europe

The energy retrofit project is located in a historical area in Boulder, CO and the area has a strict 'no noise' (read limited construction) after mid June and is in place all summer. Our schedule became tight with multiple permitting but was progressing well until a portion of our German made windows were damaged at the airport. With the delays we will be receiving the windows after the noise deadline.

In Green building techniques | Asked By Brian Hludzinski | Jun 6 13
5 Answers

Attic finishing & proper insulation


In Energy efficiency and durability | Asked By Eric Hill | Jun 7 13
3 Answers

Rainscreen behind stucco for closed-cell foam insulated wall?

I have a question regarding the need for a rainscreen between the lath and building paper on a closed cell insulated wall. What is the best way to do this, and is this necessary if the building is in southern California? I have two inches of closed-cell spray polyurethane foam sprayed against interior of the plywood sheathing.


In Energy efficiency and durability | Asked By andrew shu | Jun 7 13
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