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5 Answers

Housewrap under outsulation foam

Can you tell me if the housewrap actually serves a purpose underneath foam board?

In Green building techniques | Asked By Joshua Terry | Aug 3 17
11 Answers

Triple-pane windows for a high-efficiency cabin

1400sq. Ft. cabin...Zone 7 10,000 HDD with R40 walls and R80 in roof. Looking for ideas for windows. I'm probably looking at a manufacturer in North America for costs and timeline to get.
Have looked at H-Windows, in person and several others online, including Marvin "Tripane".

Any pluses or minuses with any of them would be helpful.


In Energy efficiency and durability | Asked By Steve Lenertz | May 29 17
2 Answers

Want to install minisplit — need advice

Hi everyone!

Our master suite has only 1 small ac vent, none in the closet or bathroom, this makes it very uncomfortable in the summer in Florida. We have a large slider window and a really small double hung window in the bathroom. This makes windows units not a good choice as I've tried to install many without success.

We have a flat roof over this part of the house so we can't run more ac to the other rooms.

3 walls are outside walls, one wall is concrete the others are basic construction, minimal insulation and no insulation on the roof. Both windows are double pane.

In Mechanicals | Asked By jgraeff | Jul 22 17
1 Answer

Installing wall exhaust fans at a downwards pitch?


I am installing a wall bathroom exhaust fan (Panasonic WhisperWall 70) directly in my external wall. I know that many people angle their ducts/pipes at a slight downwards pitch towards the exterior. There will not be any ducts, just the wall sleeve.

I was thinking of installing this bathroom fan at a slight pitch (even through installation instructions do not say to do so). Is there anything wrong with me doing this?

In Green building techniques | Asked By Rocky12 | Aug 9 17
7 Answers

Vapor drive and porcelain tile exterior walls

The nice thing about building a house on one's own is that the building gives you feedback before the finishing touches lock things in. One such lesson for me is summertime vapor drive. I have had Durock CBUs installed over vertical 1x3 furring for some time now with plans to install veneer stone later. The rainscreen gap is ventilated below and above and the insulation behind is closed cell spray foam, so no moisture drives into the house.

In GBA Pro help | Asked By Edward Mallett | Jul 24 17
3 Answers

Warm roof insulation: Ratio of air-impermeable (polyiso) insulation above deck to air-permeable (cellulose) insulation below

i have decided to convert my vented cold flat roof to an unvented warm flat roof to alleviate current moisture issues. The current placement of the scuppers will limit the amount of polyiso right foam insulation that can be placed on the top of deck; figure r20. We live in Chicago (zone 5) so this is the bare minimum required. Below the deck are 14 inch joists that are filled with loose fill cellulose insulation; I estimate the r value below deck to be r42.

In Energy efficiency and durability | Asked By Andrew Rothstein | Jul 25 17
3 Answers

Manual J, D, S

I am working on a major remodel of my 1950s house. The existing ducts are metal. I am looking for someone who can advise me on whether my existing ducts are properly sized and who can perform a Manual J and S since I will be replacing the air conditioner and furnace. I am outside Houston. I would prefer a 3rd party consultant over an HVAC company. I see some companies perform this service without a site visit.

Do I need a local company who can come to the house or can they perform these calculations accurately without visiting my house based on the floorplan?

In Mechanicals | Asked By Kasey Doggett | Jul 25 17
7 Answers

Indoor humidity levels: Magnitude of risk and solutions

I have some questions about the risk posed by humidity levels in my house and how best to address that risk. I have read lots of stuff on GBA regarding the humidity issue. Mostly I am looking for confirmation that I am on the right track. Sorry for the length of the following in advance.

In Energy efficiency and durability | Asked By Rob Shuman | Jul 25 17
3 Answers

Mobile/phone access to GBA

I have been enjoying reading contractortalk on their mobile-friendly website as well as via Tapatalk app for android. Is there any plans for GBA to become a bit more "mobile friendly", as they say? I find myself reading articles more and more on my phone and the current GBA website is not conducive for doing this. Thanks!

In General questions | Asked By Ethan T ; Climate Zone 5A ; ~6000HDD | Jul 29 17
4 Answers

Should I install HRV/ERV duct work for future-proofing?

I am in the process of planning a new house to be built in Maine. The builder likes building leaky houses, but after lots of questions and discussion we are agreeing on some targets and construction plans to support the targets. I am not sure that the house will ever get down to passive house standards, but I am thinking that I should at least put the HRV/ERV ductwork in the walls to add mechanical ventilation if needed - we will be doing blower door tests. When is ventilation required? what is the ACH threshold?


In Mechanicals | Asked By DenmarkDave | Aug 8 17
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