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!


18 Answers

Adding ridge vent and continuous eaves sensible for vaulted ceiling?

Hi,

In Green building techniques | Asked By user-6793320 | Apr 5 17
3 Answers

Insulating a shed roof addition from the 60s

Hello Folks:

In General questions | Asked By Josh Dudeck | May 24 17
5 Answers

Heat loss calculation for a ductless system

I did a thorough whole house heat loss calculation for my project when I was considering doing radiant floor heat but I have now decided to go with a Ductless Mini Split system. On one of the final tables of my spreadsheet (where I calculate design day requirements), I seem to have put in a "Boiler Efficiency" factor most likely for the heat source for the water for the hydronics. When it comes to sizing the outdoor units, should I leave that final adjustment? I attached a picture of the table showing the data.

In Energy efficiency and durability | Asked By John Brown | May 24 17
1 Answer

home in DE

Sorry the word was stud. I am addressing the interior stud cavity.

Thanks Ed

In Energy efficiency and durability | Asked By Edward Serafin | May 24 17
7 Answers

Kerf channel and thermal bridge

I am working through a shed roof design for a small shop and I have always liked protruding rafter tails. Obviously, I know these days they have been entirely eliminated due to the thermal bridging.

I will ask one question though and show a couple drawings. What if one were to cut a deep enough channel or kerf (may not be the right term) along the exterior face of the envelope (in my case, a SIP)? And then, if that channel (all the way around BTW) were filled with a foam of some kind.

In Green building techniques | Asked By John Brown | May 20 17
15 Answers

How to deal with duct-work that installed in unconditioned attic and a powered attic ventilator?

I am a homeowner of a brick ranch built in 60s in climate zone 7 and it is about 1,800 sqft.

The previous owner had the furnace and ductwork were installed in the attic and a powered attic ventilator (PAV) too in 2013. The attic floor does have some fiberglass as insulation material and it is about 8 inches. The ductwork is insulated flexible duct (supply duct is black from the outside and the return duct is silver from the outside).

In Energy efficiency and durability | Asked By TedLiu | May 22 17
14 Answers

Opinions on my exterior options

I have posted a few times regarding my situation and have been provided a lot of great information from GBA. I have not really been able to figure out what would be the best option for my situation. So i thought i would try and summarize and hope the minds here can point me in the right direction.

Current house climate zone 6
drywall
poly
2x6 16"oc fiberglass batt
plywood
Wood siding
2.64 ACH

The siding is being ripped off as it is failing in multiple places

Plan
Inspect sheathing/framing for water issues, replace as needed
Tape seams of plywood
Add Tyvek or similar wrb

In Energy efficiency and durability | Asked By Jeremy Archer | May 15 17
20 Answers

Sealing PT sill plate to concrete slab ?

I am a homeowner in the midst of a 2000 sq ft addition. Houston TX, foundation is a concrete slab. Walls (from inside out) are drywall, stick 2*4 framing with open cell foam, OSB, tyvek, air gap, brick veneer.

The builder used pressure treated 2*4s for the sill plate but there is no (capillary) barrier between the concrete and the sill plate. 3.5" of open cell spray foam is going in the exterior walls today.

In Energy efficiency and durability | Asked By Mark McFarlane | May 20 17
4 Answers

Passive solar design and HVAC sizing

I just used CoolCalc.com software (free to use online) to do a Manual J. analysis of my heating and cooling needs, since I just found out that I may need to replace my 13 year old HVAC system. One of my 2 heat pumps has a leak and needs to be recharged, and I am considering my options, so I wanted to get an accurate estimate of my heating and cooling needs. I found that the Manual J. heat loss calculations do not take into account the heat gain from the passive solar design, (except for cooling loads).

In Energy efficiency and durability | Asked By Ron Nachman | May 22 17
6 Answers

Help with vapor barrier - On-grade engineered wood

Hello All. Thanks for a great site. I have been reading quite a few Q&A regarding this topic but seems to be still confused. So I appreciate any assistance.

The home is located in the Dallas area (zone 3a I guess) and was built in 2010 with a plastic vapor barrier under the slab. There's also gutters and grading all around.

I'm trying to install engineered wood [flooring] on the first floor (on grade) and based on the consensus here is to put another vapor barrier on top of the slab as a safety measure in the long run. This is where I get confused.

In General questions | Asked By Ram777 | May 22 17
Register for a free account and join the conversation


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