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37 Answers

We have a SIP roof that will be covered with standing seam metal. Because the lumber between SIPs roof panels present thermal bridges, we wanted to add two inches of EPS to break it.

Now the question is how to put the assembly together. We already have High Temp underlayment on the SIPs panels. Can we put the EPS on top and install the metal roofing on top of that?

Or do we need to put EPS, add another layer of plywood (or furring), underlayment and then the metal roof?

In Green building techniques | Asked By Roger Lin | Nov 1 11

I am not a professional, but designed and installed my own ground-based heat pump system.

In GBA Pro help | Asked By paul willing | Nov 5 11
5 Answers

I have 2x10 rafters with a new roof. Can I use Demilec AgriBalance open-cell spray foam?

They tell me it has an R-value of 4.5. My main concern is using 3/4" tongue-and-groove pine for the ceiling. Should I use a vapor barrier or not? Thinking of using CertainTeed MemBrain. Do not want mold issues.

Thank you for any input.

In Energy efficiency and durability | Asked By jim cassidy | Nov 2 11

I recently encapsulated my crawlspace (in central Maryland). Now it's time to insulate. We want to incorporate rigid mineral wool- Roxul's RockBoard 60, to be specific. The heavy vapor barrier, a DrySpace product, goes all the way up the interior foundation walls and stops just a few inches shy of the sill for future termite inspections. If I want to insulate these interior walls with RockBoard, what is the best approach? I ask because it seems few builders have much experience with this material..particularly in this application.

In General questions | Asked By Michael Matthews | Nov 4 11
1 Answer

1920s house in TN, heating-dominated climate. The house has a full basement, completely below-grade. The previous owner had 6" batts installed in the basement ceiling, but no air sealing. Here's my question: I'm going to remove the insulation so that I can Air Seal the entire area. Do I even need to reinstall the insulation after I'm done? It's constantly 60-65 degrees down there, so it seems like conductive heat transfer would be minimum even without the insulation ( we keep the t-stat around 60 in the winter and 70 in the summer).

In Energy efficiency and durability | Asked By Adam Flowers | Nov 3 11
4 Answers

I'm working with a manufacturer of a lightweight concrete panel for a rainscreen application. The standard thickness of the panels is 1/2" and because of the size of the panels- the thickness has been changed to 1".

I need to make sure there is proper ventilation between the panels with a minimum reveal for 1/2" and now 1" panels. I was thinking 1/4" min for the 1/2" panels but I don't want to go as big as 1/2" gaps for the 1" unless its necessary.

Any help would be appreciated!!

In Green building techniques | Asked By sean Watson | Oct 26 11

Several GBA readers have contacted us to say that they prefer blog comments to be published with the oldest comment at the top of the list, and the newest comment at the bottom.

We have restored that method of listing.

In General questions | Asked By Martin Holladay | Nov 3 11
4 Answers

We have a Superior Walls basement which we are trying to add more insulation to, as part of our Passive House thermal envelope. We've added 2" of EPS outsulation to mitigate the thermal bridging caused by those concrete studs.

Other than that, the walls do provide 6-inch deep cavities which we can fill with insulation. Our initial thought was cellulose. But we are concerned about moisture potential below grade. I know the EPS outsulation helps move the the dew point out, but is it safe to use cellulose below grade?


In Green products and materials | Asked By Roger Lin | Nov 2 11
1 Answer

From Designed to Built: Delivering Your Green Home: I read the short transcript of this webinar, since I am currently working with an architect and a "volunteer" builder to develop the plans for a green home of ~ 3400 SF.

The information on your website was excellent and very pertinent to what I am presently doing....is it possible to revisit the actual webinar broadcast which I think was aired in late October and.....when is part 2 scheduled to air?
Thanks, Bob Weber

In Webinar Follow-up Q&A | Asked By Robert Weber | Nov 3 11
2 Answers

I live in a 4-story, 5,000-square-foot, balloon-framed, brick house built in the 1920s or so.

I recently did a pressurization blower-door test on the house and it only reached 20 Pa or so, but I identified some huge places where air is leaking, including the basement ceiling which is open to the floor cavity and 2 closets on the third floor which connect to the attic/outside somehow.

In Energy efficiency and durability | Asked By Karen W | Nov 2 11
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