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

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8 Answers
Heat loss calculus: solar heated siding and air space

I would like to discuss about the implications on heat loss calculations of temperature of exterior finish and its different layers (notably air space) and its effect on the delta T .

I have not found much info using the search, rather some mentions about the effect etc.. Maybe I am not using the correct terms to look it up?

So basically, when we are calculating the heat loss of an area using HDD or simply a specific time delta T, how is it affected?

A dark grey finish with a 3/4 air space under it should get pretty hot during day time when the sun is shining high...

In General questions | Asked By Jin Kazama | Apr 24 13
2 Answers
Help! My house has its HVAC ducting outside the envelope

In my area in Central Virginia, it is 'fashion' to install HVAC duct work outside the controlled envelope of living space. First floor ductwork is in the crawlspace; 2nd floor ductwork and the upstairs air handler is in the attic. Everything I've read in FineHomebuilding warns against this, but apparently local builders aren't reading FH. So, what am I as a homeowner to do within reason to remedy this situation? What is the most cost-efficient course of action short of creating new duct chases throughout the house?

Thanks -
MitchellT
owner of a gas guzzler home built in 2003 :(

In Energy efficiency and durability | Asked By Mitchell Teixeira | Apr 24 13
4 Answers
Waterproof tile backer

Is there a waterproof tile backer for a tub surround which can be used for a period of time prior to the application of the finished tile surface?

In General questions | Asked By Morgan L Washburn | Apr 29 13
2 Answers
Polyethylene sheet trapped between gypsum and wood panels: Is that wrong?

Hi everyone,

I am currently restoring an old house in a cold climate. The ceilings on the second floor were previously covered with big fiberboard panels, which I removed because they looked wavy. Under it is a layer of old wood paneling (V-joints), that used to be the finished ceiling before, which are fixed to the attic studs. Directly on top of them, in the attic, is the current insulation (looking like cellulose).

In General questions | Asked By Baril Troplein | Apr 30 13
1 Answer
Do retrofit "air tight" electrical boxes exist?

I read with great interest this article back in Feb http://www.greenbuildingadvisor.com/blogs/dept/building-science/air-leak...

However, what continues to surprise me why they have not come up with a airtight retrofit electrical box. It would seem this market is where they should concentrate? New construction and using this type of box seems like a no brainier. Where help is needed in the old drafty houses!

In Energy efficiency and durability | Asked By M S | Apr 28 13
8 Answers
Frost-Protected Crawl Space Construction

I am planning to construct a frost-protected footing/stemwall for a crawlspace in the northern Illinois region. Based on IRC guidelines, I only need to provide vertical insulation on the foundation wall to a minimum depth of 14 in. (depth to top of footing). Based on this, I have two general questions:

In General questions | Asked By Jon Sfura | Apr 26 13
9 Answers
Difficult Crawlspace Access

I have a Vermont customer who has requested that the crawlspace below their kitchen be insulated to improve to reduce cold floors and general discomfort. My biggest issue is the clearance in the crawlspace between the soil and the floor joists. I've recommended 3" of closed cell foam to the crawlspace walls and rim joists/box sills. I would recommend poly across the dirt floor and up the walls first, but my issue is the clearance. It simply isn't feasible to properly layout poly along the floor as there is less than 1 foot of clearance in most areas.

In GBA Pro help | Asked By Mike LaCrosse | Apr 26 13
3 Answers
Metal roof

Our energy consultants, Neo Virtus Engineering, evaluated our new home. The problem: it would get up to 90 degrees inside in the summer.

Their top priority recommendation was to install and metal roof. I understand about the need for high solar reflectance and thermal emissivity.

I've seen one home that has a standing seam design. Quite nice.

What metal (certainly not aluminum) would produce the highest SRI and TE? Should the panels be prepainted? Energy Star has many companies and colors to choose from.

In Energy efficiency and durability | Asked By rita addison | Apr 25 13
1 Answer
Sauna roof and wall assemblies

I am planning to build a small sauna structure in Ontario with a zero overhang unvented roof, open-joint cladding with rain screen, Delta Fassade S membrane or similar on the walls (and possibly roof), DensGlass sheathing, rock wool insulation (R14), and a foil vapour barrier on the inside with taped seams.

In GBA Pro help | Asked By Travis Marttinen | Apr 25 13
1 Answer
Build a new home or remodel old?

Here is a spreadsheet that I have created trying to break the costs down.
https://docs.google.com/spreadsheet/ccc?key=0ArcSXlgvI1xadEswVC02NVBMZzR...

Those figures are ones that I know will be similar situations for each house. As you can tell I left out any finish materials other than what it takes to seal a house up.

I'm not necessarily asking if my figures seem realistic, but I am open to opinions.

In General questions | Asked By Nicholas C | Apr 25 13
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