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

Q & A Instructions

[Click map to enlarge]

The GBAGreenBuildingAdvisor.com web site has a wealth of articles on a wide variety of construction topics. Before posting your question, you may want to check out the articles on this page: How To Do Everything. You just might discover an article there that provides the information you seek.

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

If you want to post a question, 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!


1 Answer

Details about drywall under tongue and groove as an air barrier

I have read often on gba about the importance of using an air barrier under tongue and groove and I may be over thinking it but it seems that 1/2" ultralight has the potential for more air leaks around nail penetrations due to occasional voids in ultralight and that 1/2" could more likely bust around nail penetrations and let air in versus 5/8" but before I wear myself out hanging 77 lb sheets I figured I should ask an expert.

Thanks,

Matt

Asked By Matthew Seabolt | Jul 1 15
1 Answer

Boiler upgrade recommendation?

I’m currently looking to upgrade my old boiler as it developed a small crack and is leaking. My current boiler is a P-468U-wt (151,000 btu/hr) Weil-McClain oil-fired boiler with a 40-gallon hot water holding tank.

I’m getting two different suggestions from two of my plumbers and would love some input on their recommendations. One recommends replacing it with an Energy Kinetics System 2000 and the other one is suggesting a Navien Combi-boiler.

Asked By Joe Pavia | Jul 1 15
1 Answer

How do I get and keep air out of my geothermal loop?

We have a "closed loop" geothermal heating and cooling system. 97 wells 300 ft. deep. 4 story building. 36 water source heat pumps. 72 electric water pumps. 219 ball valves.
There is no way at the high point (attic over 4 story) to release air and no easy way to add water to displace the air. The contractor keeps trying with their big pump and tank trailers to purge the system by driving the air bubbles out through the basement. No surprise to me, having observed the bubbles in my bathtub travelling upward, this approach keeps failing.

Asked By Todd Conradson | Jul 1 15
1 Answer

Where to put the water barrier?

Hi,
I'm going to retrofit rigid foam over a log home in Vermont. The logs are 6 inch pine logs, that have an R value of about 9, they have a clapboard cut on the outside so the house will not appear any different with a 3 inch layer of foam insulation with a rain screen and clapboard.

My question is about where to put the tyvek, on the out side of the foam or under the foam? We are replacing all the windows and doors. It would seem to me that the tyvek belongs on the outside of the foam and over the flanges of the new windows and doors.

Asked By Thomas Gardner | Jul 2 15
15 Answers

It's 2015 and they still build like this...

Brand new build going up in Phoenix, AZ. What you see is completely 100% framed and ready for stucco. The missing OSB sheathing is done on purpose. They do "open framing" and only use sheathing where required. The rest is open 2x4 framing.

They will stuff R-13 batts within the 2x4 walls, staple on some building paper and then put 1" of rigid EPS on the outside and use conventional stucco to finish it off.

A recent blower door test on a home like this showed 15 air changes per hour.

ALL of the duct work and air handlers are installed in the 150F unconditioned attic.

Asked By Peter L | Jul 1 15
19 Answers

Foundation capillary break & waterproofing

My wife and I are building a small home (First Day Cottage) on a full foundation with a walkout on the downhill end. I read about having a capillary break between the footing and foundation wall and it makes sense to me. When I asked the concrete contractor about it he said he's never done it (though he did remember one other customer who asked about it a couple years back). I get the impression they won't leave me much time to do it myself between pours.

Asked By Martin Frank | Jun 30 15
73 Answers

Geothermal nightmare

We truly hope you can help us. We had a geo-thermal closed loop system (into the river) put in and it went online March 2012. WaterFurnace Super DeHeater, 4 Multi-Aqua mini-splits (included for AC) and an air-handler (included for AC). 3200 sq ft home with baseboard and in-floor radiant heating. $34,000 and we have had nothing but problems.

Asked By Colleen Nicholson | May 30 13
1 Answer

Relative value of air sealing at exterior sheathing

I am trying to understand the relative value of air sealing at the sheathing. To do this lets consider cost as the benchmark. I realize that there is value beyond cost but this is an easily quantifiable benchmark and the one that seems most resonate with my clients.

Asked By Hugh Stearns | Jul 1 15
63 Answers

Attic hot after closed cell spray

Finished attic with 4 foot knee wall , duct located in knee wall to support 2 floor,extremely hot, BASF spray tite 2 inches with spray foam wraped around rafter in knee wall but with Sheetrock on ceiling just 2 in foam In cavity . Suggestions to handle heat issue. Richmond Virginia all attic seal very well thinking heat coming from rafters under Sheetrock. Thermal convection coming from rafters. Worked done in the winter, crawl space also done, house built 1994 colonial 2 story with garage with room above with dormer. Also in crawl space does it really need supply vent and return vent

Asked By Mark hippchen | Jun 27 15
3 Answers

Can a feature be added to e-mail on a reply?

If i want to follow a conversation, I have to come back to it and sometimes it ends up on the second or third page. It would be very convenient that once I reply to someone's question, I get an e-mail when it gets replied to by someone else.

Asked By Alan B | Jul 1 15
Register for a free account and join the conversation


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