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11 Answers

Formula for calculating amount of thermal mass for floor of passive solar house?

Hi all,

I'm trying to figure out how to calculate the proper amount of thermal mass to put in the flooring of the main level of a house I'm building. My goal is to size the floor so that:

1) it won't have so much mass that it can't heat up sufficiently to have a high enough delta T to warm the air over it after the sun goes down

but...

In Green building techniques | Asked By Jay Hersh | May 18 11
4 Answers

More information from Gary Proskiw on south-facing glazing

I just received a copy of an interesting e-mail exchange between Peter Amerongen, the developer of the Riverdale Net Zero project in Edmonton, and Gary Proskiw, the author of a study on the cost-effectiveness of large expances of south-facing glazing.

I have appended Gary's response to Peter to my September 2012 blog on the topic (Study Shows That Expensive Windows Yield Meager Energy Returns).

In Energy efficiency and durability | Asked By Martin Holladay | Jan 3 13
8 Answers

Pole barn fiberglass insulation help...

I have farmed a shop inside my pole barn. I have 6mil plastic under the concrete by no insulation. I do not plan to to heat and cool it very often. Also, I was given 12 rolls of unlaced R25 fiberglass insulation. The siding has been up for over a year it does not leak. My plan is air seal the exterior walls with caulk and cans of spray foam. I also plan to use a 6mil vapor barrier over the fiberglass and behind the OSB interior walls. The rolls of fiberglass are 6 feet by 25 feet and 8" thick.

In General questions | Asked By James Eric | Jan 1 13
0 Answers

Venting a tin roof

We're looking for advice regarding venting a tin roof. We have a 3 :12 shed roof, and the house is located in Quebec.

Above the roof sheathing, we are planning to run 1"x4" hemlock strapping up the trusses, followed by horizontal 2"x4" strapping under the tin.

- our thought was to bring up the sheathing from the lower edge of the deck to allow for the soffit vents (near the outer edge) to supply the air required for above the sheathing / tin.

In General questions | Asked By jessie pratt | Jan 6 13
2 Answers

Is it OK to rake cellulose insulation in attic after fresh blowing?

Hi. This is a follow-up to my question posted here:

http://www.greenbuildingadvisor.com/community/forum/gba-pro-help/26311/s...

I'm looking for some hard evidence or resources that can guide me in the right direction. From what I have been told in prior research is that it is NOT OK to walk/rake over freshly blown cellulose insulation so that it can be raked out. The installer wants to do this, and I do not.

Can someone set the record straight for me? Thanks!

In GBA Pro help | Asked By Rocky Pembroke | Jan 4 13
15 Answers

Heating suggestions for 40k BTU heating load second floor?

I am planning the second floor of a new build home in climate zone 4 which i am completing in stages due to money constraints. The building envelope is hot roofed with 4" cc spray foam on the roof deck and 5.5" of rock wool beneath that, the walls are 2x4 with cavity insulation and 2" of XPS on the outside of the wall sheathing. The walls are further air sealed with a combination of Knauf eco-seal and cc spray foam and the basement walls have 2" of cc spray foam so the envelope is reasonably tight. Fuel source available is propane which is already piped into the home.

In GBA Pro help | Asked By jack ostrick | Jan 4 13
5 Answers

Climate 4A flash and fill (BIB) vs open cell

Hi, We are building a house in MD in climate zone 4A. I am trying to decide between two different insulation methods for our walls. Our house is all brick, with tyvek, OSB and 2x6 with 16in OC. I have to decide very soon on whether to do 1inch closed cell and the BIB (blown in blanket fiberglass) or whole wall fill with open cell. The open cell is about 30% more cost than the flash and fill so I am trying to decide if it is worth the extra money. Of course my main concern is the dew point and moisture issues.

In General questions | Asked By sunil patel | Jan 4 13
8 Answers

1. What is the average cost for a Green house?

I just need an answer for my highschool science project!!!!! Thank you! This means alot!

In General questions | Asked By Rylee Godsoe | Jan 4 13
2 Answers

3. How do you think it would impact the environment if the bigger, and more developed countries switched to Green Buildings?

Again.... I really need this answered! Thanks for your time!

In General questions | Asked By Rylee Godsoe | Jan 4 13
7 Answers

Airtightness Goals

I think that we should raise or SET the bar for air tightness goals.

What is the bar? Is there an Energy Star standard? A LEED standard?

Should it be the Building America Westford Metric?
What is the Westford metric? is it 1.5 Air changes per Hour at 50p or is it 3 ACH @ 50?

How about Passivhaus Standards? 0.6 ACH50

How many out there are surpassing the Westford Metric?

Is any one besides Passive House USA meeting Passive house airtightness standards?

What is your best blower door result and how did you achieve your air barrier?

In General questions | Asked By John Brooks | Apr 25 09
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