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16 Answers

Radiant heat design details - Bosch or Navien combi boiler?

I am getting into the details of our radiant and DHW design and was looking for some feedback on the boiler choice. I have been planning on using a combi boiler and so far favored a Bosch model, but have started to wonder whether the Bosch would short cycle in my planned setup.

These are the two Combi Boilers that I am considering:

  1. Bosch Greenstar 100
In Mechanicals | Asked By Torsten Budesheim | Apr 13 16
24 Answers

Is it possible to have too many air intake vents in house?

Is it possible to have too many return Air vents in house? Of course I guess anything is possible.
But I believe it was someone on this site, that responded to an issue I have with a Lennar home.. IT was build as part of their "green' series. I lived in the house for 9 months and after my second trip to the emergency room due to air quality or lack there of in the house... I moved out... And I have been trying for 2 years to fix it.

In Green building techniques | Asked By Barry Ross | Apr 12 16
12 Answers

Tiny house building -- mold and off-gassing prevention

Hi, I am going to be building a tiny house DIY. I have not built walls myself, but have done most everything else in a house I had owned, taking it down to the studs to rebuild. One of the reasons I am building a tiny house is that I have extreme health needs. Because of lung disease and a mast cell disorder, I react to small amounts of mold, environmental pollutants (formaldehyde, cigarette smoke), foods, etc. Since these issues have become graver, I have lived in just one place I would consider relatively safe, my current home.

In Green building techniques | Asked By Emmy Haus | Feb 8 16
3 Answers

Flat roof insulation

I am about to tear off an old tar & gravel roof as well as the existing sheathing. I know that some of the old fiberglass insulation was water damaged and expect that to be true of more rather than less. The plan is to add a modest 1/4" per foot slope (that's all the room we have). I will insulate between the 2x8 16" on center rafters, deck with 3/4" ply, add polyiso rigid, another layer of 1/2" ply, and finally we will lay down a mod bit roof. Over the top will be a modest roof deck. All of this is in a zone 4 region.
Here are my questions:

In Energy efficiency and durability | Asked By Scott Wittenberg | Apr 6 16
5 Answers

Insulation for roof rafters under a metal roof (not-vented)

I'm the homeowner, so I'm not 100% informed on the ins an outs of metal roofing yet. I have a metal roof going on a renovation project and from what I understand the roof is not vented. We have a mixture of depths in the rafters, some are the original 2x6 (i think those are 6") and then a bunch of new TGIs. It's a 2-story wood frame house.

I haven't meet with the contractor and his insulation sub-contractor yet, but I'd like to go in a bit more informed. What is the best approach or insulation type for the rafters where there is a metal roof that isn't vented?

In Energy efficiency and durability | Asked By David Kaplan | Apr 14 16
0 Answers

Do you have new windows? CEMAC needs your help

Did you recently replace the windows in your home? If so, you can help advance research that could reduce the cost of replacement windows.

The Clean Energy Manufacturing Analysis Center at the National Renewable Energy Laboratory is studying the costs of installing energy-efficient windows in homes—from the cost of the windows themselves to costs for installation and labor— and we’re collecting as much data as possible. We are searching for copies of actual invoices from energy-efficient window installations.

In Green products and materials | Asked By Jorn Aabakken | Apr 15 16
9 Answers

Can a multi-head minisplit be electrically separated to two different electrical meters?

I'm wondering if single outdoor mini-split units, that operate two or more interior wall units, can have the electrical demands of the interior units metered separately?

In General questions | Asked By Brad Hardie | Apr 11 16
11 Answers

Zone 7A existing cabin crawl space headaches

We recently purchased a existing seasonal lakefront cabin built in the 80s in northern MN. We are remodeling and converting to all-season occasional use and trying to address the vented crawl space. It is damp and there is some mold on floor joists, but I don't believe there has been standing water and the soil composition is sand. The problem is access: there is very low clearance in most areas (only 6-8" in some spots). Our contractor has proposed 1) adding rigid insulation to the perimeter block foundation, or 2) raising the cabin and adding two more rows of block.

In GBA Pro help | Asked By Deb Edwards | Apr 13 16
8 Answers

Judge my insulation plan

Hi All. I've been browsing GBA and I think I've got a good insulation plan for my remodeling project.

House Stats:
-Fully gutted for remodel
-6" block walls
-Built-up, low-slope roof (no attic--2x8 joist between roof and interior ceiling)
-House currently has a foam roof (looks like spray foam)
-Phoenix, AZ (dry, hot climate)

-We added added furring strips over the existing so that there is 1.5" of space between drywall and block

In Energy efficiency and durability | Asked By Will Clinton | Apr 14 16
4 Answers

Is mold growing under an encapsulated crawlspace a concern?

On a project we are doing , the home owner is very reluctant to encapsulate the crawlspace because he believes that mold will grow on the ground side of the vapor barrier and the spores will end up migrating into the house. We both know that having a completely airtight ground barrier is impossible so slight infiltration is expected. Has anyone documented this problem occurring? He wants to close the vents, install a loose fitting vapor barrier, and a dehumidifier.

In General questions | Asked By Mike Labesky | Apr 15 16
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