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4 Answers

How best to insulate framed walls inside stone walls?

I have an old stone farmhouse with approximately 18"thick sandstone walls in good repair. Inside the stone walls there is a layer of 1" thick boards horizontally, then 2x4" studs, then another layer of boards, then a layer of plaster and then paneling. I am renovating the upstairs first, and have the top fire blocking off of the wall cavities. I can blow insulation down from the top everywhere except below the first floor windows, so I want to do this while I have the upstairs walls open.

In Energy efficiency and durability | Asked By Karl Schwingle | Feb 9 14
5 Answers

Heat loss calcs, and how to size a water heater for hydronic heating

We are building a home using slab hydronic heating in Central Oregon and our HVAC guy recommends 2 electric water heaters to carry the load (no gas avail). He says that our demand will be about 52kBTU/hr when the temp is 0F outside and the slab is heated to 70F. So 2 x 50gal water heaters rated at ~30kBTU each provides enough with buffer. He says he used Wrightsoft Manual J to calculate. we don't really want 2 water heaters if not needed.

In Mechanicals | Asked By bob tong | Feb 17 14
5 Answers

Sweating windows

What would cause my windows and doors to sweat when it gets cold out if the indoor humidity is low? They are new windows and doors. The windows freeze shut when it gets about 10 degrees and the door handles freeze as well. I don't know the exact indoor humidity, but I can tell you it is low by how dry my skin and nose are in the morning. I keep the indoor temp about 65 to 70. Can anyone explain the problem and how to fix?

In General questions | Asked By ben g | Feb 16 14
1 Answer

Advanced wall construction idea. Will it work.

I live in a zone 6a and plan to build this summer. I have been researching and drawing different wall construction details, and keep coming back to this design. However I can't find much about it online or in discussion with other professionals.

My wall section outside in would consist of:
house wrap (breathable drainage plane)
3/8 plywood
2x4 stud wall 16 oc with roxul batt. Framed to underside of floor decking.
1"-1-1/2" extruded styro with ship lap joints taped. Again to underside of floor decking. This will be my vapour barrier and thermal break.

In Energy efficiency and durability | Asked By Kevin vesey | Feb 17 14
8 Answers

Wall Design Questions

I am planning on building a new house inland a bit from midcoast Maine (Zone 6) and have been pondering issues related to exterior wall design, taking into account what I have read here and elsewhere. I want a relatively high-R wall (~mid R-30’s) and have been thinking about the following designs.

Design 1: 2x6 wall with ½” drywall, R-23 Roxul, OSB/plywood, 2-3” Roxul Comfortboard, rainscreen (e.g., 1x3 strapping), siding.

Design 2: 2x6 wall with ½” drywall, 2” Roxul Comfortboard (inside the studs), R-23 Roxul (between studs), OSB/plywood, rainscreen, siding.

In Energy efficiency and durability | Asked By Rob Shuman | Jan 27 14
1 Answer

Is bubble wrap duct insulation non-toxic?

I have an exposed duct in the utility room that just got repaired and wrapped with foil bubble wrap. There is now the smell of off-gassing plastic. Is that safe? What is the alternative?

In General questions | Asked By Zak Sinclair | Feb 16 14
1 Answer

ACC block wall


In Energy efficiency and durability | Asked By Issac Tate | Feb 16 14
1 Answer

Adding insulation to walls with existing fiberglass insulation in them?

Adding insulation to walls with existing fiberglass insulation in them? Walls of our house on the lower floor are cold to the touch, yet they do have insulation in them. Is it possible to add more?

In Energy efficiency and durability | Asked By Jeremy Radigan | Feb 16 14
1 Answer

Are we asking for trouble with our window/flashing/insulation method?

I help to build houses with a Habitat for Humanity affiliate south of Houston, TX (Zone 2A) and I would like your thoughts on how we weatherproof the homes.
We use standard 2x4 construction, with OSB sheathing. (Cavities and attic floor are filled with blown in rock wool)
Flanged vinyl single hung windows are installed as per Texas Windstorm Regulations. We do not put any window pan or any other drainage plane/ water resistant barrier in before installing window.
We do use Dow Weathermate 4" Flashing Tape over all four flanges (working upward).

In Plans Review | Asked By Steve Young | Feb 16 14
4 Answers

Envelope air tightness sanity check

Designing a "Contemorary Industrial Passiv Ranch Haus" for DIY build in SW Colorado (CZ6B). Working through data entry in PHPP now and I know the one level elongated ranch style is sub-optimal for PH design. It's 2250 ft^2 (OD) with conc. slab and shed roof. Floor/ceiling/wall envelope area is 6982 ft^2 and volume is about 25789 ft^3. An optimal PH two level cube would have envelope area of 4531 ft^2 and volume about 19125 ft^3. I'm over that by 154% and 135% respectively.

In PassivHaus | Asked By Chuck Jensen | Feb 15 14
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