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!


15 Answers

Mini-split exterior heat collector unit in attic?

What parameters should be evaluated in considering the placement of the 'exterior' unit of a mini-split heating system in an attic which is generally warmer than the outdoor winter environment in Northern Vermont? Why not collect some of that heat from sun on the shingles as well as some of the usual heat losses in a 35 year old wood frame/fiberglass insulated house? Is there a 'recharge' rate factor that would probably deplete that heat source faster than it would normally be replenished?

In Energy efficiency and durability | Asked By Kerry Batdorf | Mar 17 14
1 Answer

Is the R-value of a PVC ceiling better than 6.4 mm RhinoBoard?

I need data on PVC ceilings' R-value and the advantages of PVC ceilings over RhinoBoard.

In Energy efficiency and durability | Asked By Johan Van Vuuren | Mar 20 14
18 Answers

CertainTeed vs James Hardie fiber cement shingle

We decided to go with a fiber cement shingle or lap. Wanted to get advice/experience with CertainTeed or James Hardie. Heard James Hardie material is difficult to work with and bad for the environment (when they make and off-gasing when cutting and nailing it). Thanks for your advice! - Karen

In Green products and materials | Asked By Karen Miller | Aug 16 10
2 Answers

Interested in environmentally friendly sealants

I am looking at sealing the concrete slab of my basement, a large living space.
1. I have examined three products: Enduroseal, Xypex and Lithi-tek LS 9500. All claim to emit no VOCs. Enduroseal hardens into nonsoluble silicate minerals. Xypex hardens into nonsolluble crystalline structure. Lithi- tek LS 9500 hardens at the nano level (I don't know more than that.) Are there other environmental considerations besides VOCs for a living space? Might they form dangerous dusts? How does one assess such products environmentally? Is there any authority to consult?

2.

In Green products and materials | Asked By Chris Campbell | Mar 14 14
15 Answers

Does fastening WRB or building felt with cap staples work as an air gap for a rain screen approach?

I'm wondering if the space created by the plastic cap staples will work as a "cheapskate's" rain screen under vertical ribbed steel siding? I don't know the exact thickness of the cap staple, but from memory I would say it's a bit over 1/16".

My wall assembly is as follows: 29 gauge vertical rib steel siding, Typar WRB, 1/2" cdx sheathing (taped and caulked as exterior air barrier), 2"x8" stud wall with dense pack cellulose or cut and cobble polyiso cavity insulation), 2" rigid polyiso interior sheathing taped, and 1/2" acx interior sheathing.

This is for my wood shop.

In Energy efficiency and durability | Asked By Rick Van Handel | Mar 12 14
9 Answers

Without natural gas, is there a better option than electric baseboard heat?

I am currently designing a home to build, that is to be the best compromise of sustainability and affordability. This home is 800 s/f and will have a passive solar heat design, and a wood stove to use our local biomass resource of beetle kill pine, however I need a third heat system for the house (what the City considers to be the primary system). Although natural gas is very cheap in CO, we decided we would rather put the money to run a gas line and install a furnace toward a net metering PV system, since we have the optimal climate for this.

In Mechanicals | Asked By Curt Lyons | Mar 7 14
12 Answers

Metlund D'Mand hot water recirculation pump

I am thinking about installing hot water recirculation pump to reduce hot water usage. Metlund D'Mand hot water recirculation pump seems to be a good choice since it's passive and does not use energy until you push a button when hot water is needed.

In Green products and materials | Asked By Rian Bart | Dec 2 10
5 Answers

Two layers of poly sheeting?

Would it be okay to put two layers of poly under a basement slab? The layers would consist of 4" of gravel, one layer of poly sheeting, one layer of XPS foam board, another layer of poly sheeting, and then the concrete slab.

Would this be beneficial or would it be overkill? I am building in central KY if that has any implications. Thanks for any input.

In General questions | Asked By Morris Farris | Mar 17 14
5 Answers

R-25 exterior rigid foam in Maryland, USA

I was given 50 sheets of 4x8 R-25 rigid foil faced foam that was left over from a commercial building project. I also have 35 sheets of 4x8 R-10 blue board. I live in Maryland just outside of Washington, DC. I plan to add an addition on to the house this summer. The existing house is all masonry with no insulation. I would like to use the 2" R-10 board to cover the existing brick section and them add cement siding and new windows,

In Green building techniques | Asked By James Eric | Mar 17 14
5 Answers

How to insulate/seal in tight spaces

Hi, I've got about 14" where the ground floor was bumped out 2.5" over the walkout basement. The joists run perpendicular, so there are about a dozen little "bays" roughly 30"x14" where the outside ir circulates and makes it feel like you're stepping on a slab ice in the kitchen above. I've caulked outside, but bridging fitted at the openings to the basement, along with various wiring runs and vents make it virtually impossibly to get a caulk gun or expanding tape into all the corners inside the bays.

In Energy efficiency and durability | Asked By Laura Braceland | Mar 17 14
Register for a free account and join the conversation


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