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14 Answers

Why is there condensation on the return ducts and mold in the attic as well 60% humidity throughout the home?

This home has since been remodeled, including all new metal duct work and insulation. The issue that we need to resolve is the high humidity in the house at about 60-65% even though the unit is running efficiently. There is quite a bit of condensation on the return ducts in the attic as well. We have had two reputable Heating and Cooling Contractors come to assess the situation to no avail. The owner attempted to contact the original Mechanical contractor, but has not been able to speak to anyone yet.

Asked By Jimmy Miller | Sep 1 15
4 Answers

Building Codes

I often see posters refer to building in areas with no codes. Here in Canada, although we have areas in which there are no permits or inspections, the building codes are enacted to cover the whole of each province or territory. People building in areas where the codes are not enforced have the same obligations to follow them as elsewhere.
Are there areas in the US where there are no codes and you are free to build as you like?

Asked By Malcolm Taylor | Sep 2 15
4 Answers

Roof ventilation ideas

I'm trying to add attic ventilation for my whole house fan, as the manufacturer states that I need a total of 4.4 sq. ft. of free air. I currently have gable vents, but they're located right above a window and the attic air gets sucked right back into the house (even when the window is closed, to some degree, and I'd like to open that window anyway). So I'm thinking of sealing off the gable vents and getting all the ventilation from the roof.

Asked By Robert Shelton | Aug 26 15
1 Answer

Is it ok to step the slab thickness over the footings to accommodate insulation between the slab and the footings?

I am building an addition on my home near Ottawa and I am adding two new sections of full-foundation on either side of the existing foundation, which has no under-slab insulation. I am adding 3 inches of insulation under the new slab, however for various reasons it is not practical to bring the 3 inches of insulation over top of the footings and right to the inside edge of the foundation wall.

Asked By Chris Seligy | Sep 2 15
7 Answers

Any hydronic system controls with low standby electricity consumption?

I was feeling good about the changes I'm making to reduce the electricity consumption of my hydronic system: a Grundfos Alpha ECM pump that is consuming only 16 W when it's running, and Taco "sentry" zone valves that use about a watt when on. But I measured the power consumption of controls last night, and it can add up to almost as much as the pump: 3 W for an aquastat, 6 W for a Taco "switching relay" circulator control with one zone on, and 4 W of standby power for the 40 VA 120:24 VAC transformer that powers the zone valves.

Asked By Charlie Sullivan | Sep 2 15
7 Answers

How can I properly vent my tiny house roof (it has cross member framing instead of rafters)?

I have the framing almost complete on my tiny house, but I have run into a stumbling block. Framing the roof with cross members instead of traditional rafters made a lot of sense because the shorter span allowed smaller lumber for more head space and less weight, but upon further research my plan for venting is not going to work (I know - proper planning prevents poor performance). See attached picture for framing structure.

Asked By Ryan Reed | Sep 2 15
8 Answers

Attic insulation upgrade

I'm struggling with getting the correct answer on how to proceed with upgrading my attic insulation.

I live in Pittsburgh PA climate Zone 5A.
My existing attic space has batt insulation on the floor with no air barrier and is vented at the gable ends.

I would like to spray foam on the underneath of the roof deck sheathing in-between the truss joists and on the gable end walls to meet the required R38.

I'm struggling to understand if I should use open cell foam or closed cell foam.

Asked By Forrest Watson | Sep 1 15
2 Answers

Ducted mini-split serving multiple floors

I am attempting to break my house design into zones such that I can use one mini-split for each zone. I am having trouble simultaneously satisfying two pieces of advice from this forum. In "Rules of Thumb for Ductless Minisplits," Martin says that one ductless head can serve a maximum of about 1100 square feet. That is based on distribution, not capacity. I realize that it is a rule of thumb that might not apply to a super-open floorplan, but if I violate that rule, I should have some justification.

Asked By Reid Baldwin | Sep 2 15
2 Answers

How were the IECC Climate Zones maps developed?

Were high resolution zone maps developed and then adjusted to match the county boundaries—perhaps with a generous safety margin—or something different entirely?

My brothers' houses, 150 feet apart, are in different counties. One house is in Zone 3 (Johnston County, NC), the other in Zone 4 (Harnett County, NC). Should my Zone 3 brother be concerned that he's really experiencing Zone 4 conditions (and vice versa)?

A generous safety margin might imply that some true zone 3 climate locations are well into Zone 4 map areas which can have a large impact on those with a tighter budget.

Asked By Stewart Akerman | Sep 2 15
2 Answers

New 20+ SEER Variable Carrier heat pump w Greenspeed Intelligence system creating moisture and performance problems in the crawl

I had to replace 2 -13 SEER HVAC split systems in my house about 2 years ago do to some Sandy storm damage. One split system was a 90% gas furnace with a 3 ton 13 SEER AC and the other was a 2 ton 13 SEER heat pump. Both the air handlers were originally in the crawlspace, which I hated, and I wanted to come up with a better set up with the new replacement systems.

Asked By Bruce Howe | Sep 2 15
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