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

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2 Answers
What's the financial impact of a home's 50-year operating energy vs. initial cost?

Has a good analysis been done comparing the financial/ environmental impact between the operating energy needed over 50 years ( or longer) and the initial cost/ environmental impact of building a house? This seems like an essential green question to me.

Thanks for any help on this question.

In General questions | Asked By james Corsa | Aug 6 11
3 Answers
Is it advisable to use a SIP system over a swimming pool?

Architects details call for a 20 mil duraperm barrier on the underside of 8 1/4" SIP's with a ice and water shield on top. The roof is metal.

In Energy efficiency and durability | Asked By Arlis Palmer | Jul 29 11
9 Answers
Solar thermal system and collector choices

I'm renovating a house in the Seattle area. Part of the renovation includes changing the roof lines for good solar exposure. Heating will be hydronic radiant upper floor (1900 ft2) and hydronic wall panels in finished daylight basement (1400 ft2). Floors will be connected with an open staircase. Air sealing and high levels of insulation are being incorporated. Being on Puget Sound, we're sacrificing insulated west walls for an expansive view of the Sound using a lot of Serious windows. Very efficient windows but windows none the less.

In Mechanicals | Asked By Greg Lindstrom | Aug 5 11
6 Answers
Reducing solar gain on existing windows

Customer of mine has a house with a wall of windows facing southwest. In the summer the living room gets too hot near these windows, which are mostly unshaded. They are soft coat two layer low-e from about 1993. I'm wondering about a couple of strategies for reducing solar gain without replacing the glass or sash. One would be to install some sort of shading across the header above the large units... something that projects more or less straight out and shades the glass without interfering with the view.

In Energy efficiency and durability | Asked By David Meiland | Aug 4 11
4 Answers
Installation of polyiso roofing insulation panels

I am planning to install 4 inch polyiso insulation panels on the roof deck of my Cape Cod style home located in Cape Cod Massachusetts. There is currently 6 inches of fiberglass insulation installed between the 12 inch rafters up to the collar ties. The insulation is then located between the collar ties just above the ceiling of the upper floor. There is a vapor barrier between this insulation and the ceiling sheet rock. There is a small vented area beneath the roof above the collar ties.

My questions:

1. Can I install the polyiso panels and leave the current insulation in place?

In Energy efficiency and durability | Asked By Neil Wintfeld | Aug 3 11
5 Answers
Are my SIPS panels deteriorating?

Seven years ago we constructed a shop/studio building in Freeport, Maine. Climate zone 6A, less than a half mile from salt water. Humid climate. The building is built on a slab with radiant heat coils in the slab. Post and beam construction with SIPS panels. The builder erected the frame, then put MR wall board over the frame before installing the SIPS panels. Building has a metal roof. Exterior is wooden siding over Typar and Cedar Breather. We keep the building heated to 60 in the winter, there is no AC for summer. Building is very tight.

In General questions | Asked By Ralph Harding | Aug 5 11
3 Answers
Proper way to insulate an unvented slate roof?

Hello GBA,

Any best practices on the proper way to insulate a home with an un-vented slate roof?

Keeping the envelope defined as the attic floor would dictate that the attic needs to be vented. I am struggling to figure out how one would go about installing adequate attic ventilation where a slate roof is present.

Re-defining the envelope to the rafters, one would likely use a vapor impermeable spray foam. I am dubious about spray foaming the underside of an 80 year old roof....

Any thoughts or experiences?

Thanks!

In Energy efficiency and durability | Asked By Art Vandelay, AIA/LEED AP+, Zone 5 | Aug 5 11
1 Answer
Best way to design a restaurant basement wall system?

I am designing a build-out of a restaurant in an old (c. 1926) vintage building in the Chicago area. Because of space limitations, the prep area will be in the basement.

The basement walls are Chicago common brick with surprisingly little efflorescence. The basement is definitely damp, and we will be putting in a perimeter drain tile sump pump system with dimple sheeting at the joint between the wall and the new slab to allow any seepage to go directly into the drain tile system.

In Green building techniques | Asked By Nathan Kipnis | Aug 4 11
1 Answer
I want to be a green building advisor in India

Hi,
I want to be a green building advisor in India, so I want to gain the complete knowledge about the whole course.

I want to know, how can I make it possible? Do I need to go through any specific course, and I would also like to know whether it can be done...

Thanks.

In General questions | Asked By Manoj Sharma | Aug 4 11
5 Answers
Polyiso over plywood - low-slope roof

I'm adding a 16x28 1-story addition to my 2-story house. Roof pitch is 1/4"/ 1-foot. It will be used occasionally as a deck.

I'm putting 3.5" poly-iso on top of 5/8 plywood; GAF Liberty self-stick roofing on that.

What's the best way to insulate between the joists?I see much discussion here of problems caused by multiple vapor barriers.

In General questions | Asked By john harrier | Aug 3 11
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