Q&A: A Forum for Green Building Experts and Beginners

[Click map to enlarge]

Please register for a free account or sign in to ask and answer green building questions.

The usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration:
Under the box labeled "More explanation," look for the words "File attachments."
Click that, and you should be able to attach a photo.

Thanks for joining the conversation!


8 Answers

Wall vent vs. roof vent

We are installing a custom wood range hood and can't decide between venting through our wall or heading through the roof. The duct is 6" round. Going through the roof the run would be about 3-4' straight up. Roof is pitched about 5-12 and the vent cap would land right around 30" from the eave.

The range sits on an exterior wall, so heading though the wall would give the run a 90 degree turn and about 2' of ducting. The siding is 4" lap fiber cement. Any pros or cons or suggestions to persuade me one way or another?

In Mechanicals | Asked By Matt Cibula | Jan 25 15
2 Answers

What's the best way to integrate rain water to a condo system?

Hi,

First of thank you for having such a wonderful forum to share infornation on. I have found this place very usefull in the past.

To my question: im designing a 7 story medium sized condo that will house 6 families. Im thinking of integrating rain harvesting to the building as we some times get droughts and i hate to see all that rain water go to waste. I think it should be regulation to have some sort of backup water sytem just incase the mains dry up. But for now will just be using rain water for the watering closet.

Some numbers:

In Mechanicals | Asked By Osman Naskali | Jan 24 15
2 Answers

Windows - Canned spray foam vs. ExoAir foam tape

I noticed that builders will use canned spray foam to fill in the gaps between the window and the window bucks. The spray foam is messy and needs to be trimmed back on the interior and exterior since trim work cannot be done properly. I also question spray foams ability to expand and contract as window frames do over the course of the life of the home. I also have seen smoke pencil tests done after spray foam and there are noticeable air gaps between the window frame and buck.

In Green products and materials | Asked By Peter L | Jan 24 15
11 Answers

Longevity of double wall construction?

I'm currently designing a new home as an owner/builder (construction to begin later this year) for the Edmonton, Alberta area. I have several years of building experience, however I have to admit that I've only ever done status quo jobs - 2x6 construction with fiberglass batts, a poly vapor barrier and OSB sheathing.

In Green building techniques | Asked By Matthew Sokalski | Jan 23 15
2 Answers

What is the best heat-pump water heater for Zone 6A?

So you guys have more than convinced me to go with a heat pump water heater. I am going to have 9.3+kW on my roof. Should I just buy a heat pump water heater or buy a Marathon type electric water heater and add on a heat pump?

In General questions | Asked By brad hardie | Jan 23 15
4 Answers

Slab on grade floor repair

About 20 years ago two rooms were added onto this house, both have a slab on grade and the floor tiles are cracking, i had to repair a wall in one of the rooms, and it looks like the floor was the slab with a styrofoam sheet on top (2-3 inches thick), with 1/4in plywood, black adhesive (tar?) and kraft tiles on top (i have no idea what these tiles are called, they are 12x12 in, used in many schools and older buildings, are less then 1/4 in thick and are the same fibrous material all the way through (and i'm hoping not asbestos, they were installed about 10 years ago i am told).

In Green building techniques | Asked By Alan B | Jan 22 15
4 Answers

Whisper wind exhaust only ventilation durability with continuous run time?

Don't believe any of us know how long a Panasonic Whisper wind fan can be expected to run if exhausting 60 CFM out a bath ceiling if hard wired to operate continuously through time? Anybody have a guess?

In Green products and materials | Asked By Rick Jenkins | Jan 22 15
12 Answers

Ventless heat pump clothes dryer

Would a ventless heat pump dryer contribute to indoor humidity and heat levels?

I thought the unit was all self-contained and would NOT contribute to increasing moisture and heat in the room it was located in. If anything, it would only dispense water from the drain line into a sink drain but that's about it. Am I wrong?

In General questions | Asked By Peter L | Sep 5 14
2 Answers

How to insulate a partially open unvented ceiling/roof?

We've had a leak and ceiling damage in a 50 yr old house with a flat roof in zone 4A. Part of the ceiling is gone, damaged, part still intact with its fiberglass.So there are cavities with part fiberglass. There is no ventilation in the cavities. This part of the roof was re-roofed a few years ago and some sort of foam board was added on the exterior (presumably between the old rubber and new TPO) at that time. The is no condensation currently with the cavities open.

In Green building techniques | Asked By Katie Dorst | Jan 23 15
13 Answers

Using too much electricity?

I just completed a 1043 sq ft story and a half cottage with a 351 sq ft garage apartment over a detached single car garage. I have two mitsubishi hyper heat splits in the cottage and one in the garage apartment. The cottage has a 27KW ecosmart tankless and the garage apartment has an 18KW. The garage apartment is never used and my usage is between 60 and 74 KWH per day. I'm gearing up to call the utility and the electrician to check things out. Is this atypical for an all electric home this size?

In Energy efficiency and durability | Asked By Andre Jones | Jan 19 15
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!