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22 Answers

HRV / HVAC engineering help in Ontario

My building inspector came to do my HVAC rough-in inspection today. After he had ignored my e-mails and phone calls for 2 months, I gave up and just bought the Zehnder unit I wanted. The last thing he had said to me was he was "sure it would be fine", and he'd call me back in half an hour (which he never did, called him again and got another promise of a return phone call that never happened). So now he claims he sent an e-mail telling me the Zehnder didn't meet the Ontario building code, and needs a report from an engineer to allow it to pass.

In Mechanicals | Asked By Trevor Lambert | Apr 26 18
2 Answers

Best practices for fastening lath / 3-coat stucco over rigid foam

There seems to be some debate over how to anchor 3-coat stucco over rigid foam while maintaining <1/64 deflection to avoid cracking. It seems that for:

<=1" Foam, Standard Wide Crown 2" Staples into Studs are Adequate
2" Foam, Lathe & Plaster Washers and 4" #10 Screws every 6"
4" Foam, Furring strips or add additional OSB/CDX Sheathing over Foam and staple lath

My question is,

1. What would you all recommend for 1-1/2" Foam (R-Max Polyiso)?

2. Would there be any advantage to a hybridized system of staples and screws/washers - i.e. screws every 12", staples every 4"

In Green building techniques | Asked By Zane Bridgers | Jun 21 18
7 Answers

Vapor retarder for exterior walls Zone 4

Good afternoon,

The insulation guys installed un-faced batts in the exterior walls in my house in Nashville Tn. Should I install a smart vapor barrier (certainteed membrain) over the insulation?

- The house was built in 1964 with thermo ply sheathing. As seen in the image the sheathing is very
leaky. I have done my best at sealing the sheathing with caulking and great stuff foam.

Thanks! ~Bob

In Energy efficiency and durability | Asked By Bob Harshman | Jun 21 18
13 Answers

Need some unbiased input on these 2 proposals

So I've gotten 2 proposals from different geothermal contractors and I just wanted some unbiased opinions on the work and equipment. Both proposals came in at around 40k so there's no huge up front cost benefit from one over the other.

Company A is proposing a 3 ton Hydron YT Series 2 Stage heat pump
Full Load: Cooling 41,200 BTUs at 20.9 EER, Heating 29,100 BTUs at 4.5 COP
Part Load: Cooling 31,500 BTUs at 31.3 EER, Heating 23,300 BTUs at 5.1 COP

Company B has 2 options, a Waterfurnace Series 5 single stage model 030 or double stage model 038

In General questions | Asked By milhouse21386 | Jun 20 18
15 Answers

Do I need an HRV/ERV for a house built in 1947?

I have a three-bedroom house, one bathroom, in Worcester, Massachusetts. It was built in 1947, and measures 1,100 s.f.

After purchasing it, I decided to upgrade the insulation in the walls and in the attic and air seal the home, and install new windows. All which was done through the Mass Save program. After completing, all the energy bills went down.

But the problem now is the house has high humidity and seems to be too tight and cause hard breathing. I have noticed mold that I did not have before. Also get headaches more often than I used to.

In Mechanicals | Asked By Will82 | Jun 14 18
17 Answers

Re-sealing failing SIP roof panels

We have a 7 year old SIP panel over a timber-frame home. We have noticed for several years significant condensation of moisture to the point of dripping from light fixtures and ceiling fans located in the peaks during hot summer days. Roof is a stone-coated metal shingle panel over Grace Tru-flex underlayment.

In GBA Pro help | Asked By Passagyrs | Jun 19 18
3 Answers

Single minisplit for AC?

Looking for feedback on adding AC to a ~1600 sq ft ranch in central NJ. Current setup is a window unit in the bedroom and a 1980s 220v beast of a wall unit in the dining room. Together they do all right in those worst weeks but for the most part we've just been toughing it out. I'm on a well shaded lot and the house stays reasonably cool during the summer, but also a bit damp. So hoping to dehumidify with the AC and of course cool the place down during the hottest weeks of the year.

In Mechanicals | Asked By Jeffesonm | Jun 20 18
11 Answers

Air Barrier Location

I'm in the process of beginning our new home in the next few weeks. We're located up in Newfoundland, Canada, just around St. John's. We're planning on incorporating a double stud wall to increase the R-value of the home. The plan is, from outside to in, : R8 Comfortboard, Tyvek, Plywood,, 2x6 wall with fiberglass batt, 6mm poly, and 2x4 wall with fiberglass batt which will contain all of the electrical and plumbing.

In Energy efficiency and durability | Asked By Dan C | Aug 6 17
5 Answers

Carbon monoxide detectors in a fuel-free house?

Just a quick sanity check here. Our house will have no fuel burning devices (also no garage), so code requires only smoke detectors, not combination detectors. Is there any reason at all to have them? The cost difference is fairly small, but if they are completely pointless then I will leave them out. Is there any other possible source of CO?

In Mechanicals | Asked By Trevor Lambert | Jun 20 18
9 Answers


Hello all.

I am building a house in a hurricane/northeaster prone area of Virginia, and in an area that has potential for flooding to boot.

Keeping in mind that i dont have an unlimited budget, what do you think would be the best long-term, flood resistant, hurricane resistant home?

I love the idea of SCIP, but im not sure i can find skilled shotcrete people and the cost looks prhibitive

I like SIP, but i worry about flooding and hurricane resistance.

Im leaning towards ICF, but thinking it may be cheaper (and maybe "just as good") to just to build CMU with foamboard

In Green building techniques | Asked By user-7043474 | Jun 20 18
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