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8 Answers

Double interior rock wool

Working on plans for my next home. After lots of research on here and others I am considering the following wall assembly. From the exterior... wood siding, tar paper, 1/2" plywood with taped joints, 2x4 ,16 on center wall stud with roxul, uniterupted layer of 1 1/2" comfort board, layer of a variable perm vapor barrier (taped seams and such), then a layer of 2x3 installed 2 ft. on center as battens for electrical with shallow boxes , second layer of comfort board fit between the battens, drywall finish. I am in zone 5 in northern ct.

Asked By scott mangold | Dec 8 16
2 Answers

Tiny home heat pump (Mitsubishi or Fujitsu) for a mostly empty house

I am in the process of renovating a 1-level 470 sq ft basement walkout condo in Kittery, ME. It has two floors above it. I've consulted a contractor, and don't agree with their suggestion for a mini split. So, I've started doing research!

Asked By Kate Harris | Dec 9 16
6 Answers

Optimum air gap for skylight

Context: a 14x7x6' tinyhouse with 4"-thick polyiso insulation on all surfaces except the windows, which, for reasons that aren't relevant here, must be on the roof.

Several hours of research shows that the optimum air gap for a typical double-glazed window ranges between 13-30mm depending on whom you ask. Charts show that U-value tends to bottom out at around 13mm and slowly climbs up from there. From this research I've gleaned hints that the glazing material and the angle the window is mounted at are factors, but I've been unable to find out how they matter, so I turn to the Community.

Asked By Geva edhrven | Dec 8 16
22 Answers

Another crawl space in the Northwest

Hello all, I have a 1150 sq ft rambler house in Fall City, Washington (near Seattle), zone marine 4c. I am currently in the process of redoing the crawl space. I have pulled the damaged and rodent infested insulation down, and removed the town vapor barrier. It seems I had some rodents that were digging past the foundation and getting into the crawlspace, ruining everything.

Asked By David Meyer | Nov 28 16
3 Answers

We plan to use Obdyke Hydrogap between the Hardie board siding and the Zip wall

We plan to use Obdyke Hydrogap between the Hardie board siding and the Zip wall. Will that be an adequate drainage plane? Or are furring strips also needed?

Asked By Courtney McCracken | Dec 5 16
7 Answers

What is the relationship between air source heat pump and indoor heat pump water heater?

I am sure this has been analyzed here before, but I want to check my reasoning. A criticism of heat pump water heaters is that they cannibalize the home heat source and so during the heating season perform exactly as electric water heater efficiency. However if the heat is provided at COP 3 from an external air source mini split, then am I correct that the heat that is being "borrowed" by the heat pump water heater is also COP 3 and so year round the heat pump water heater functions at COP 3 or better?

Asked By ven sonata | Dec 5 16
15 Answers

Is this a reasonable solar bid? — and other questions

Howdy folks,
I got my first solar bid today, from Consolidated Solar Technologies. For a 3.2 kW ground-mount array in Albuquerque, New Mexico, the total cost before the federal tax credit is $16,300, and $11,410 after the credit. This works out to $3.56/watt.

One thing I worry about is that their calculator shows a higher projected output than PVWatts does. Their tool showed 6,500 kWh yearly, but PVWatts shows 5,844 kWh. This is supposed to be a net-zero-enabling array, so I don't want to underproduce. I'm using 6,500 kWh for my yearly usage

Asked By Nate G | Dec 5 16
2 Answers

Insulation options to add R-value

I had the opportunity to reroof this spring and add exterior rigid foam. I used foil faced polyiso 2.75" thick. Due to time and money constraints I applied a single layer taped and foamed. Through fastened wth .5" OSB cut into 3" strips. A new OSB deck was installed and asphalt shingle roof on top of that.

Asked By David Mosijchuk | Nov 23 16
9 Answers

Can this assembly work for a flat unvented wood roof in Atlanta, GA (Zone 3)?

Hi all, I am building a flat un-vented wood roof in Atlanta, Ga (Zone 3) and I want to make sure I am doing it correctly. The assembly that I have so far is:

-TPO roofing
- 1/4" exterior grade drywall cover board
- 2.5" Tapered insulation
- 4" Rigid tapered Insulation
- 2" Rigid Insulation
- Waterproof Coating on osb / or peel and stick waterproof membrane
- 5/8" osb
- 2x10" beams (all at the same height)
- 2" closed cell spray on foam insulation
- 1 layer 5/8" type x Drywall
- Resilient channels
- 1 more layer 5/8" type x drywall

Asked By A Patel | Dec 6 16
5 Answers

Interior walls acting like exterior walls

New construction in zone 5. We have 3 interior walls that we have to build up still where the vaulted ceiling meets the flat(see pic). We are planning unvented on the vaulted side (3" closed cell, and fill the rest with cellulose, but just blown in cellulose on the flat ceilings. How would you recommend I build and insulate this wall? I figure I need to treat it like an exterior wall, so drywall, studs filled with fluffy and 3" of rigid foam?(that is what we are doing for our other exterior walls). Thank you in advance.

Asked By Michael Brackett | Nov 29 16
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