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2 Answers

Attic open-cell foam: off-gasing / odor

We have a traditional 1966 two story home, dual-zoned home in Atlanta (zone 3A). On April 18th we had our existing inadequate fiberglass insulation removed and open cell foam installed in our 1200 sq ft attic. We have had odor / off-gasing problems since. On cool, cloudy days it’s not very noticeable but on hot, sunny days the odor is quite pronounced and our second floor A/C (handler in the attic) is not usable as it blows in the odor/gases. We’ve been living with open windows and fans upstairs since. The odor is closer to the paint-like I have read about, not the fish-like.

In Green products and materials | Asked By User-7075353 | May 22 18
9 Answers

Is there any way around putting a heat source in every bedroom?

I was speaking with an HVAC guy in my area today who reminded me that code says we have to have a heat source in every bedroom. We're planning on putting a single head ductless minisplit in our 1450 sf high performance home (to be built next year). Are there other exceptions/solutions out there, or do I just stick a Cadet heater in every bedroom and disconnect them after the inspector checks it off his list?

In Building Code Questions | Asked By Alyssa Hoyt | Feb 4 16
7 Answers

Unorthodox foamless insulation system

I've been a long time reader and spent countless hours on BSC trying to learn all I can on building science. The biggest thing I've learned is how much I didn't know. Long story short...we have been making improvements to our home, some cosmetic and some as efficiency when they align. This winter our dated central air heat pump tried to catch on fire(long strory) and after a few months of research we successfully replaced it with three mini splits and they are fantastic! It was unplanned but extremely successful.

In Green building techniques | Asked By Russell Boudreau | Jun 19 18
14 Answers

Mortar bridging and droppings

General question on Mortar Bridging and Dropping workmanship.(CZ4)

Here are a few images of some brick veneer on a house. Its not mine, but it is from the builder I will be using. I've read that droppings and bridging are "bad" but I don't know what constitutes good vs typical vs poor. So I've attached some pictures to get others viewpoint on the quality of this work. There is a single layer of tyvek and then OSB behind that, and I'd say ~1" of space behind the veneer, at least where there is not bridging.

In General questions | Asked By Stephen Cook | Jun 16 18
10 Answers

Plumbing too close to edge of slab

A plumber set a vent pipe within a 1/4" of the edge of the slab on one of our jobs. When we told him to move it, he cried. I was surprised to find that this was not covered in our specification and I could not find it in code documentation. In fact, I could not find it anywhere. We have all seen concrete on the edge of a slab bust out around a vent stack or a piece of rebar that was too close to the edge of the slab.

So what is too close?

In Project management | Asked By Hugh Stearns | Jun 18 18
7 Answers

Vapor permeance of thick foam sheathing and board seams

I have read that at a certain thickness, all foam boards (eps, xps, and polyiso) lose their vapor permeance, effectively rendering them vapor retarders with very low perm ratings. Does anyone have a link to the research behind these findings and if so can I be pointed in the right direction?

I am hopeful that the effective thickness at which this condition occurs for each foam is stated on the research but I will hold further questions till I have read up on it.

In Energy efficiency and durability | Asked By Sash057 | Jun 18 18
11 Answers

Anyone use Dennyfoil to block fumes from a renovation?

A Contractor is renovating two walls in my apartment near the windows. I’m very chemically sensitive. one suggestion is to place dennyfoil on the wall to block the fumes from coming into my apartment.

Has anyone used it successfully for this purpose and have any suggestions
On how to reduce the risk of mold growing. One person suggested applying the foil tightly to the wall using tape. To not use the air conditioning. And to consider getting a dehumidifier when it’s humid in my apartment.

She also recommended I consult with a building science expert. Any advice or feedback?

In Green products and materials | Asked By Daisy63 | Jun 5 18
6 Answers

Circulating air between floors

I don't see a lot of air mixing between floors in my (partly finished) house. We had a hot day here yesterday (34C / 93F), and by sunset the first floor was 22C / 72F while the upstairs was around 24.5C / 76F. This doesn't surprise me, as hot air obviously rises, plus the 1st floor has the benefit of the slab heat sink. What surprised me is that this morning the temperatures were the same. I would have thought with minimal heating going on during the night, they would have equalized at least somewhat.

In Interior design | Asked By Trevor Lambert | Jun 18 18
9 Answers

Ceiling insulation for a room addition to my house

I'm planning a room addition, 16 x 16 with a 6/12 gable roof and cathedral ceiling, zone 6. I'm not yet committed to anything specific so would like to run this scenario by folks for advice and opinion. I'm wanting to avoid the 5-6 inches of exterior foam (R-25) that would be needed if I went that route. And, I would like to go unvented. Would the following scenario work?

In Energy efficiency and durability | Asked By Howard Gentler | Jun 16 18
5 Answers

HVAC duct size versus grille size

For proper air being returned to the HVAC unit that is the size of the duct have to correlate to the size of the grille for the return air? So for a 12 inch air filter grille what is the largest size return duct that could be attached to that for proper operation?

I’m getting air pressure coming from the attic through the switches ,outlets ,and around the drop ladder in a different zone than the one with what I believe is undersized return.

Thanks Rich

In Mechanicals | Asked By Richt1022 | Jun 18 18
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