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8 Answers

How green is my cloud?

I can't verify, but I read sometime recently that there's less embodied energy in buying a CD than in storing it on-line. Which got me to thinking about these monster servers that must be sprouting like mushrooms. I have a vision of us all living in lovely net zero homes, served by our own individual off-site servers consuming a Fukushima's worth of juice.

No real question. Just wanted to share my cheerful thought before the weekend.

In Energy efficiency and durability | Asked By Dan Kolbert | May 17 13
3 Answers

Quickly listing neighborhood amenities by LEED category

I am working on several LEED for Homes Midrise projects which are pursuing points under LL5 Community Resources. LEED outlines several categories of resources, like:

Arts and entertainment center, Bank, Community or civic center, Convenience store, Daycare center, Fire station, etc.

In Project management | Asked By Kris Knutson | May 17 13
5 Answers

Say you want a door but you also want to use it for solar gain. Is there a type of door style/material/size thats best?

I can't seem to get values for doors from manufacturers or when I do, the SHGC drops precipitously once you put the glazing in the door, e.g., Sungate 500 SHGC drops from .6 to less than .4 when put in a swinging fiberglass patio door. Of course glass size is limited to about 2 ft width, although the length is long. How I get what I need in SHGC in a south facing door. Do I change door style, size of door/glass, material, glazing brand, ? etc. Thanks

In Green products and materials | Asked By Lisa Young | May 16 13
3 Answers

Some help with estimation of wall assembly cost?

We are in the process of designing a passive house and are working with PH certified architect/consultant. But for now, builder's knowledge would be needed: a back of the envelope calculation for the cost /sf of this kind of wall assembly: fiber cement board w/ rain screen, fiber board, dense packed cellulose, OSB, dense packed cellulose, drywall. The wood framing will most likely be w/Larson trusses. The R-value we are trying to achieve is around 40. The house is a duplex with gross sf area of ~4500. Would be good to know the material & labor separately. Why do I need it?

In PassivHaus | Asked By Lucyna de Barbaro | May 16 13
2 Answers

Sealing a dry sump

My basement is fairly dry and well above the local water table
and hasn't had any water ingress over any of the major storm
events we've had, and has never had a sump pump. So I don't
really care about storm water; what worries me is the potential
for internal plumbing leaks as there's no way for the basement
to drain until it basically fills all the way up. So I'm
thinking of putting in a sump pump but into a small well that
*doesn't* connect to whatever gravel/earth/whatever is underneath
the slab -- it would be connected to the slab and sealed in and

In Mechanicals | Asked By Hobbit _ | May 16 13
1 Answer

Does anyone have experience with or an opinion of the Dow Powerhouse solar shingle and cathedral ceilings/ roofs?

The cathedral ceiling/roof is unvented, closed cell insulated. Will this solar shingle properly vent moisture upward from the plywood decking? Will there be any problems with running the multiple wiring conduits to the inverter in the basement?

In Green products and materials | Asked By JOSEPH POLAND | May 16 13
3 Answers

Re-using brick pockets in an exterior wall

I am working on the design phase of a rowhouse renovation in Baltimore, Maryland. This rowhouse is 14'x50' and is an end-of-group, with an east facing exterior side wall. Existing floor joists sit in "brick pockets" in this exterior wall.

In General questions | Asked By Charles Chiampou | May 14 13
4 Answers

Can exterior foam be combined with interior spray foam?

If I have walls and/or an unvented cathedral ceiling that are insulated with closed-cell spray foam from the inside, can I also have rigid foam on the outside of the sheathing to limit bridging?
Just wondering if it's somehow a bad idea to have the sheathing sandwiched between two layers of foam.

Thanks, Chris.
(This is for Ottawa, Canada, equivalent to zone 6A.)

In Green building techniques | Asked By Christopher Solar | May 13 13
7 Answers

Thermal mass lessened with overlay over slab?

I have a passive solar off-grid home that works extremely well with a 2 in. concrete slab that is finished with decorative concrete stain/paint. However, the slab and stain/sealer are completely defective and very likely have to be replaced, but one party is proposing a concrete overlay product be put atop the existing slab. The overlay product (ArtCrete Deck Coat, I think it is) consists of two parts--1) Portland cement, aggregate, and a stain, and 2) a modified acrylic latex resin.

In Energy efficiency and durability | Asked By K Tot | May 13 13
3 Answers


I am finishing a screened porch into a fully-insulated room, to be part of the house and used year round. I understand Roxul is an excellent choice for exterior walls. Is a vapor barrier necessary and, if so, can someone suggest how to install. Tks for your help.

In General questions | Asked By Roni Collier | May 14 13
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