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10 Answers

Rigid foam and dimple mats

My concrete contractor will be applying bituminous waterproofing tar on the outside of the basement walls up to grade. We are considering putting 4" of rigid to the exterior of the concrete after that. Someone advised us to also put up a dimpled waterproofing membrane, but is his necessary if we are applying the 4" of rigid foam?

In Green building techniques | Asked By Nina in CNY | Sep 30 17
6 Answers

flex duct material for ventilation

It was recommended to me by a couple of independent sources to include a short run of flex duct between my HRV and the supply and return manifolds, for noise control purposes. The idea is to decouple the unit from the ducting as a means of reducing vibration transmission. I've looked at several options:
1. Vinyl dryer duct. Very flimsy, has a pretty nasty smell to it, probably not a good choice from an air quality standpoint.
2. Foil dryer duct. Also very flimsy.
3. Semi-rigid aluminum dryer duct. Seems too rigid to actually achieve the goal of decoupling.

In Mechanicals | Asked By Trevor Lambert | Apr 11 18
3 Answers

Exterior Door Thresholds

We are building a double-stud house in Iowa -- and have a wonderful builder to work with, even though this is the first such house he has built. The problem we are having is with exterior doors. We want the doors to open to the interior, and so they are "innies". But the widest threshold we can find for an exterior door is 8 1/2". All suggested solutions are complicated and/or limit the range that the door can open. Does anyone know of a company that makes a 13" threshold?

In Green building techniques | Asked By user-6870177 | Apr 11 18
10 Answers

Furring strips and Roxul

I just applied for our building permit for a major remodel, climate zone 3 coastal, headed for a ‘very good house’. I’ll be the owner builder.

The 2x4 wall is sheathed in CDX, blueskin, 1.5” Roxul, 1x4 furring strips, cladding (stucco downstairs, banding divider, then fiber cement siding upstairs).

In Green building techniques | Asked By Phil Boutelle | Apr 3 18
1 Answer

Is it ok to use a commercial warp over a fluid applied WB?

I am building an apartment building in Kirkland WA by lake Washington in a high wind location. Currently I am using a liquid applied weather barrier( Barritech VP by Carlisle). For additional protection from the wind driven rain and air intrusion, I would like to use an additional layer of warp such as Tyvek commercial warp over the fluid applied WB. My question is whether this is a good or a bad idea? would the combined layers allow or prevent any moisture that gets into the wall cavity to perm out? I am grateful for your help and guidance.

In Energy efficiency and durability | Asked By user-7020549 | Apr 10 18
1 Answer

How can we contact/communicate with members who have posted on blog?

Would like to contact a member who has posted a question on a blog as I have a similar project that was described by this member. How do I contact another member?

Thank you

In Webinar Follow-up Q&A | Asked By trent willey | Apr 11 18
3 Answers

ERVs and VOCs

Quick question: One of the advantages of using an HRV or ERV is to exhaust household air that may contain off-gassed VOCs. ERVs exchange both heat and some moisture between the incoming air and exhaust air.

Does it also exchange some of the VOCs, so that the incoming fresh air may contain a portion of the VOCs we are trying to exhaust out of the house? I'm not sure how it could exchange moisture, but not gaseous chemicals.

In Mechanicals | Asked By Debra | Apr 10 18
17 Answers

solar quotes & info feedback

concerned with proper sizing and associated costs of course...

we’ll be building a "pretty good" 100% electric house in the the white mountains of NH, USA and this is a huge question that we need to answer. of course i have the requisite fear of undersizing…

some rough details:

1350 SF conditioned space
will be using mini splits for heating
heat pump water heater
possibly condensing/heat pump dryer
wife may go all electric car in future

quotes from one company all prices USD:

option 1:

In Energy efficiency and durability | Asked By John Williams | Mar 27 18
16 Answers

Wood Stove with HRV

We live in an 1942 brick colonial (about 1,000 sq ft each level) in Minnesota. We have both a wood stove and a forced air furnace. We burn about 3 cords a year which covers most of our heating needs and the furnace fills in the gaps. We also rely on the furnace fan to circulate the warm air from the stove throughout the house. Not perfect, but it keeps things pretty evenly warm. Last year, we had a blower door test done and were told our house was too tight after new windows, doors and adding closed cell spray foam to the attic and rim joists.

In Mechanicals | Asked By BC-L | Apr 6 18
8 Answers

Main Floor Cantilever

Hello. I am working on a project where the main floor is cantilevered over the concrete foundation wall. I am having a hard time finding details showing the sealnt, barriers, and insulation for the cantilevered floor. The details I do have show a cantilever over a wood frame wall, not a concrete foundation wall.

any suggestions would be greatly appreciated. Thank you.

In Green building techniques | Asked By user-7049485 | Apr 9 18
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