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3 Answers

SIP "Larsen studs"

From my local SIP maker I can get 10' lengths of 1 3/8" wide 7" deep SIP for about twice the price of a 2x6, I'll complete the stud by Adding a strip of Thermoply 7" wide on one side.using polyurethane glue and some staples. This makes a quasi "Larsen" truss that I'll build my outer walls with. I can insulate between these "studs" with ordinary low cost mineral wool bats for r30 in the cavities. These SIP studs with he Thermoply "web" are about r23, pretty awsome, I think.

In Plans Review | Asked By Jerry Liebler | Sep 15 17
3 Answers

Radon mitigation with sealed crawlspace and partial walkout basement

Does anyone know of a resource that addresses radon mitigation for a foundation area with a sealed crawlspace and partial walk-out basement on new construction in Zone 3A?

I am assuming the crawlspace and basement mitigation systems can share an exhaust pipe and I have a good understanding of the under slab portion for the basement. So, what is the best method for the crawlspace?

In Mechanicals | Asked By Norman Bunn | Sep 10 17
3 Answers

Spider Tie concrete house?

Showed up on Facebook today; I didn't find it in a search on GBA.




(I live in a home with an ICF foundation. We had a "miss" on bracing at one location and ended up with a small "bow" that, fortunately, we were able to take out by milling down the EPS. This video seems to infer that no external bracing is required?

In Green building techniques | Asked By Andrew Bater | Sep 16 17
11 Answers

Cape Cod--Building a maintainable insuated roof (on the cheap!)

We are purchasing a Cape Cod style home near Dayton, OH (climate 5A, but the southern edge). I've read many of the helpful articles here (thanks, Martin, for the notes about Capes here: http://www.greenbuildingadvisor.com/articles/dept/musings/insulating-cap... . I can't say I wasn't warned!)

Other articles I found very useful:

This situation:

In Energy efficiency and durability | Asked By Mark Waldron | Sep 11 17
13 Answers

My HVAC guy disagrees with PH Planning Package

The Passive House Planning Package indicates that the heat load for my house should be 7,722 BTU/hr (4.4 BTU/hr-sqft, and the cooling should be 3,573 BTU/hr (2.0 BTU/hr-sqft).

I gave these numbers, and the entire PHPP file to my HVAC person. He was dumbfounded by the low numbers and ran our plans through a detailed Manual J calculations. Now, he admits that he cannot account for the superinsulated slab, but he came up with much higher numbers.

The quote is for various versions of a Carrier 38Mxx / 40xxxx (3 ton heat pump. So much for heating the house with a hair dryer.......)

In Mechanicals | Asked By Steve Young | Sep 13 17
3 Answers

I am researching the capability of a 40-gallon electric hot water tank

If water is tested at 2 AM and it takes 3 mins to reach 143 degrees (no one used any water for the previous 9 hours) temperature outside is 62 degrees and someone used the water at 2 pm (washer, dishwasher being used) temperature outside is 89 degrees, would it still take 3 mins to reach 143 degrees?

In General questions | Asked By Durazo | Sep 15 17
3 Answers

Mechanical ventilation

Reaching out for some input on mechanical ventilation. We are building a new house and like anyone else, we are on a tight budget. We have decided to have our HVAC system designed and sized properly and going to use the folks at Energy Vanguard for the design. For the ventilation, as much as we'd love to include that in the services invariably the recommendations would more likely than not be cost prohibitive.

In Mechanicals | Asked By Thomas Roberts | Sep 15 17
6 Answers

Gable access to attic?

The house we are designing will have an attic with roof trusses. No ductwork in it, just lots of insulation. The only time I think it would need to be accessed would be to check for or repair roof leaks. Properly air sealing and insulating an indoor attic access hatch seems somewhat expensive.

Does anyone access their attic through an exterior door in the gable wall - where it would need to be weatherproof, but not air-tight or insulated? Not sure if that is feasible or practical.

In General questions | Asked By Debra | Sep 14 17
22 Answers

Solar assisted Heat pump vs normal air/ground source ? Home in Nova Scotia

I have been researching different heating techniques for a new build in Nova Scotia

4 acres of land
On the ocean (Ocean side is NE- SE)
2 story home + Walkout basement
Main level: 1,600 sqft + 2 car garage (730sq ft)
Upstairs level: 1,050 sqft 3 bedrooms/2 bathrooms (550 sq ft less than main level due to open ceiling)+ loft on garage approx 600 sqft (potential 4th bedroom and den) 450
Walkout Basement : 1,600 sqft (10 foot ceilings) with windows on eastern and southern side

In Mechanicals | Asked By snarbs | Sep 14 17
15 Answers

A few air-sealing questions (at the sheathing stage).


My plywood sheathing with be my exterior air barrier and my housewrap will not be (not taping the bottom of the wrap).

I have a few questions for some tips and advice for you. The question number corresponds with the picture number

1) What is the best way to airseal my outdoor panel box here in this picture?

2) The cutout around my bathroom exhaust fan has a lot of room around it. Will it be sufficient to just tape around or should I stuff some sort of insulation in the gap first?

In PassivHaus | Asked By Tommy87 | Aug 5 17
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