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39 Answers


I'm building a house north of Stowe VT using SIP over timber frame construction with R-40 walls, and R-48 to R-53 roof SIPs (different thickness are being used in order to make the ridge line heights match on roof areas with differing pitches).

There seems to be some confusion among my contractor, the SIP installers and myself about what to use for 2 parts of the roof system:

1) material to use over the top of the T&G ceiling boards and under the roof SIPs

2) material to use over the top of the roof SIPs and under the standing seam metal roof

In Green building techniques | Asked By Jay Hersh | Jun 18 11
8 Answers

Remodel of early 60's modern house on Puget Sound. Shed-style roof with 1.5 in 12 pitch. Private drive is elevated above house so roof is visible as you approach it. House is L-shaped with attached garage. Garage and L wing roofs are oriented for solar exposure with a substantial PV installation (Solar World 235) on both. Panels will be angled to 30° using either off-the-shelf Unirac components or custom aluminum racks that we plan on attaching with S-5 clips. Central portion of roof is low on the east and slopes up towards the west, where we get the most weather.

In Green building techniques | Asked By Greg Lindstrom | Aug 17 11
1 Answer

The cooktop will be layed on a standard granite top, and the oven, which is electric, will be installed in an existing 30" base cabinet. Is there any special material I need to use to insulate the oven?

As I have never mounted an oven under a cooktop, and with the top being gas, I want to make sure heat build up won't be a problem. I also am concerned with the gas line that will have to run near the oven!

Thank you for any help with this!

In General questions | Asked By Ryan McCormick | Aug 22 11
3 Answers

I have been looking at concrete SIPs. The place I have been looking suggests a a shell of 2 1/2 inch concrete on each side with an interior of 7 inches of XPS.

Okay, this sounds good. You get high thermal mass on the inside and the exterior shell protects the xps from bugs, etc.

But is there a way to make it better(cheaper)? Could it work 2 sheets of xps up against the concrete walls, but then fill the space between the walls with dense pack cellulose (3 inches or maybe even increase it to 5 inches)?

In General questions | Asked By Robert Nemoyer | Aug 18 11
3 Answers

My Massachusetts house was built in 1901 and renovated in 1998. As part of the renovation we added R30 fiberglass batt insulation to the vented attic. The second (top) floor has forced air heat from an airhandler in the attic. Ducts have insulated jackets. We have about a dozen recessed canister lights in the second floor ceiling. Most of the top floor has the original beadboard ceiling, and the fiberglass was just laid down in the attic joist bays over the beadboard.

In Green building techniques | Asked By bil knopp | Aug 19 11
6 Answers

A recent question with regards to heating a basement slab via radiant due to chilled air got me thinking of an idea I had regarding a scheme I had.

We're all more or less in agreement that HPWH are a 'Good Thing' given their ability to extract heat at a fairly high COP. Their main downside in a cold climate being their contribution to the heating load.

We're also more or less in agreement that Passive Solar in cold climates is a 'Great Thing' since the sun is free eh?.

In Green building techniques | Asked By John O'Brien | Aug 22 11
14 Answers

Will try to keep this short....looking for opinions/discussion on window choices for new home we're building. We're located in eastern Nebraska so we get the "best" of types of weather....hot/humid summers and frigid cold winters. House will be on a lake and back of house will be nearly due north. Vast majority of glass of house is on the back (north side)....trying to maximize lake views. Front of house has only a couple windows (one in a closet, one in the laundry) and sides of house also have minimal glass, so solar heat-gain really not a factor for us.

In General questions | Asked By Dave W | Aug 7 11
6 Answers

I have read a little about it on the internet, but I was curious if anyone has experience with it.

I am interested in alternative methods of cooling, and this is something that is of interest to me. I had John Yellott as a professor at ASU, who was a very early solar pioneer, developed the Skytherm system with Harold Hays for passive rooftop cooling in the desert, and built a lithium bromide A/C system for his home in Phoenix.

In Mechanicals | Asked By Nathan Kipnis | Aug 22 11
5 Answers

(Are you all getting tired of my questions yet?)

We have a couple of design choices we can make with our new home and wanted to get feedback on "standard" doors vs. sliding glass doors. Northern exposure. Will either be a "full daylight" standard (french?) door or sliding glass. Looking for input on pros and cons of each from a thermal protection standpoint.

In General questions | Asked By Dave W | Aug 9 11
9 Answers


I have a new, well insulated (walls R-40, Attic R-70) and well sealed (350cfm@50) 3000sqft home in Northern Vermont. The max heat loss is roughly 20k/hr. I heat the home using two Mitsubishi Hyper-Heat mini splits that are located on the first and third floor. The home is all electric.

In Mechanicals | Asked By Graham Mink | Aug 20 11
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