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5 Answers

Air and thermal barrier continuity in ceiling over garage

Good Morning All,

I am building a new structure (northern end of zone 3) and will be using the 100-year wall approach with a low slope metal clad roof (yes white colored). 2 x 4 construction on the exterior walls (yes, I know about OVE) with Zip cladding, then 2 - 1" xps lapped sheets on the exterior and most likely rockwool in the cavities.

Piece of cake? Except!!! the ceiling over the garage (which sits under the 2 stories above). The garage will most likely be CMU with no insulation (cold space).

In GBA Pro help | Asked By leo kloop | Aug 25 14
26 Answers

Review my home insulation plan

I'm building a new house, and would love to hear feedback on the insulation plan. It can be found here: http://lazukars.bitbucket.org/house.png

DESIGN GOALS:

- Have a consistent insulation pattern up from the basement and up through the roof. In this case XPS on the exterior and ccSPF on the interior.
- Eliminate thermal bridges wherever possible.
- Double the insulation required by code

CONCERNS WITH THIS DESIGN:

- Foam Sandwich: The current sandwich of XPS on OSB on ccSPF will create OSB rot. The OSB will not be able to dry to the interior.

In Plans Review | Asked By Ryan Lazuka | Aug 18 14
20 Answers

Forced air is forced air ... isn't it?

All this talk about ductless minisplits is making me dizzy. If a forced air furnace gives a bad atmosphere in a building, doesn't a minisplit per room just give many bad atmospheres?

Dana reminded me on another post that a forced air furnace increases infiltration/exfiltration. Well, why doesn't a minisplit heater or cooler do the same?

In General questions | Asked By flitch plate | Aug 19 14
4 Answers

A few questions on my cathedral ceiling plan

Hi All, I've been reading through the forums for the last month or so as I'm preparing to reinsulate my cathedral ceiling in my master bedroom and home office. I've found tons of great information so far and just had a few questions on my current plan to see if I'm on the right track.

In Energy efficiency and durability | Asked By Edward Dziarcak | Aug 22 14
17 Answers

Off-grid house needs... gasp!...air!...gasp!

Hi,
I need some advice...preferably before I cut a bunch of holes in the walls or ceiling and find out that this was a pointless venture.

So the details:

900sq foot one level, mostly open plan, highly insulated and sealed home.
Heating climate...like really... a lot. -40 C is not unheard of for stretches of time. More typical is -20 C

The house is powered completely with PV.

Heat is supplied by radiant slab, a bit of passive solar. I am also putting in a small wood stove in the next few days.

In GBA Pro help | Asked By keith ahlstrom | Aug 21 14
11 Answers

Is foam under the basement always recommended?

I have been thinking about the benefit of putting XPS/EPS foam under the basement slab, and it has gotten me thinking.

I am building in zone 6, where it is quite hot for a couple of months in the summer, getting up into the 90s, and cold in the winter, getting down to the 10's (Fahrenheit) on and off for a couple of months.

In Green building techniques | Asked By Stephen Youngquist | Aug 21 14
2 Answers

Using rigid foam insulation in an unvented roof

Hello, I would like advice on insulating my garage. It has cinderblock walls and an unvented hip roof with no ridge or soffit. Rafters and sheathing are exposed and the outside is metal panels. I can't really alter the outside appearance of the home due to my local historic society (home built in 1842). My question is, can I glue/screw rigid foam board directly to the underside of the roof sheathing, in between rafter bays, then finish by screwing plywood or drywall directly to the foam board. Is there risk of moisture build up (between foam board and sheathing) if I do this?

In General questions | Asked By Dan McGonigle | Aug 22 14
19 Answers

Excess humidity - HVAC system too large

So, My AC system died last spring, and I was prepping to put new windows (impact resistant, low e) in my house... My house is approx 2200 sq.ft in Florida, south of Tampa... Zone 2A

I had a 4 ton system, and knew that would be too big as a replacement, but my HVAC tech replaced it with what was here and said he could tune it... Now my house averages 55%rh or higher... Up into mid 66-67...

In Mechanicals | Asked By Chris Marriner | Aug 18 14
2 Answers

Crawlspace question climate zone 6

Question about sealing up a crawlspace with foam.

Our house at some point had an addition on the front put on. It is more like a bump out that is 6' x 16'. They did dig for a foundation and built a cinder block wall to hold this up. There is a dirt floor in the crawlspace that is above the level of the dirt outside the block wall. This crawl space is only 18" deep stays dry and only accessible through an old basement window well window that they built this in front of. Needless to say I never went in there.

In General questions | Asked By William Heiden | Aug 22 14
2 Answers

DIY blower door test?

This page describes how to build a DIY blower door:

http://www.builditsolar.com/Projects/Conservation/BlowerDoor/BlowerDoor.htm

Basically you use a furnace blower and a cheap magnetic or tube-of-water manometer. You can't finely tune the speed of the blower like a professional blower door, but given the few built-in speeds of the motor, you can generally find a speed that yields close enough to 50Pa that you can extrapolate the CFM50.

In Green building techniques | Asked By Nick Welch | Aug 21 14
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