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6 Answers

Access to crawl space through masonry stem wall

My small, one-story, wood-framed house will be built on a masonry stem wall three courses (24") high that will support a raised wood floor. My locale requires continuous rebar along the top course, so the top course will be bond-beam blocks. I need to install an access opening through the stem wall (through the interior floor is not an option), and code requires at least a 16" x 24" opening.

In General questions | Asked By Jeff Cooper | Jan 28 16
2 Answers

Long electrical wiring home runs


In General questions | Asked By C. Maglio | Jan 28 16
6 Answers

Duct sizing for Fujitsu 9RLSFCD concealed duct unit

Hi All,

I am planning to install Fujitsu 9RLFCD concealed duct unit and can’t figure out way what size duct should I use and how to determine how many CFM does each room need. I have a heat loss done for each bedroom.

The plan is to put unit in the lower level aka basement (it’s split entry home) and run the duct work to the 3 bedrooms thru the floor. All three bedrooms are next to each other and would not require more than 4-6ft of ducts to each bedroom.

In Mechanicals | Asked By Alex Frost | Jan 28 16
4 Answers

Does OSB sheathing need to be installed horizontally over advanced framing studs 24"OC?

A client building in Zone 4 says their engineer told them, "in our wind speed and exposure (105mph - C) neither OSB nor 15/32” CDX can span between studs at 24”oc without being run horizontally". This is problematic because they are not planning on using rigid foam over the sheathing and are concerned about increased thermal bridging and air leakage resulting from expansion joints and additional blocking needed for horizontal installation. I have seen many houses with vertical OSB sheathing over 24" OC studs so this is new to me. Has anyone else heard of this?

In Building Code Questions | Asked By Elizabeth Coe | Jan 28 16
1 Answer

Cathedral ceiling with service cavity

I am building a vented cathedral ceiling, but am now looking at adding a service cavity to allow space for recessed lights without penetrating my air barrier.

I'm looking at some ultra-thin LED lights, which run about 1.5", so I was thinking I could simply use 2x2s or 2x4s laid flat against my existing rafters. The transformers are short as well and can fit into a shorter 1.5" junction box. They are designed to be placed directly against insulation, so they don't need any space behind them as well, though they'll still have 1" or so, and space all around.

In Energy efficiency and durability | Asked By Peter Hsu | Jan 28 16
9 Answers

Conflicting insulation advice from spray foam installers

I'm trying to determine the best solution for insulating our conditioned attic/unvented roof/cathedral ceiling and our walls. I have read so many articles/blogs/reports on GBA and from Building Science that my head is spinning. I know more about Joe Lstiburek then I care to, and I realize that fights can break out in blogs over who knows more about vapor drive. I'm probably staring my own theory war by posting this, but here goes. This will long, but I want to cover the details of the build upfront.


In General questions | Asked By Shawn Sanders | Jan 27 16
12 Answers

Question about cut and cobble rim joist insulation

I'm planning on insulating around the rim joist of my 1901 home using the cut and cobble method with rigid foam insulation sealed shut with spray foam. I know that normally you fit the pieces right up against the sheathing and between the joists. However, mine are a bit different than all of the diagrams and photos I've seen. My studs seem to go all the way down through the sub-floor to the rim joist. So between most (but not all) of my floor joist, there's one stud, either against the floor joist or in some cases right in the middle of the two.

In Energy efficiency and durability | Asked By Tim Ifill | Jan 25 16
11 Answers

Condensing dryer advice

Does anyone have any experience with these? can you get the HRV to distribute the heat that is created? do they work fairly well or does drying time increase substantially? Do they make too much vapor for a high performing home in zone 6 in the winter time? Thank you in advance. And thank you GBA you make a world of difference for me, a developer of Net-zero homes!

In Green building techniques | Asked By Susan | Jan 20 16
4 Answers

Good range hood damper and thermal break?

Looking at range hoods, it seems as though most manufacturers realize that their built-in dampers don't work very well as many of the manuals contain text like:

Cold Weather Installations:
An additional back draft damper should be installed to minimize
backward cold air flow and a thermal break should be installed to
minimize conduction of outside temperatures as part of the vent
system. The damper should be on the cold air side of the thermal
The break should be as close as possible to where the vent
system enters the heated portion of the house.

In Green products and materials | Asked By Nick Hall | Jan 27 16
2 Answers

Can Panasonic ERVs be on programmable timers?

I am installing a couple of the Panasonic spot ERVs and the directions clearly state not to put them on a solid state controller. The directions state that the harmonics from a solid state controller can effect the motor and make it run noisily and even the possibility of fire. This would limit you from using any programmable timer that I know of. I hear of people putting these on programmable timers thou. Am I missing something? Has anyone had any experience with this? Thanks ahead of time.

In Mechanicals | Asked By Kail Zuschlag | Jan 27 16
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