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5 Answers

How does a vapor retarder work in a Northern climate?

I guess I'm asking a Building Science question here, but in a Northern Climate (e.g., 6A), What does an interior vapor retarder actually do, especially if the air barrier is at the sheathing layer for a typical 2x6 wall with fibrous insulation? I can understand an interior temperature of 68% with a relative humidity level of 35% (and the dew point that must be kept higher than any condensing surface, which seem to the real parameter of interest in all of these discussions), and I can understand the temperature gradient (and its associated "humidity" gradient increase with dew point change).

In General questions | Asked By Bob Manninen | Jan 6 12
22 Answers

Cathedral Ceilings Retrofit - Zone 5

Hi All,

I have house just north of Boston, in Zone 5. It is a contemporary home built in 1983 with nearly 100% cathedral ceilings. I have an active leak on one of the roof sections, and as such will be replacing the roof very shortly. The roof section is 6/12 pitch 22 feet wide and 28 feet high with two layers of asphalt shingles.

I would like to address some of the shortcomings of the existing roof system which are:

In General questions | Asked By Bernie Simon | Dec 31 11
3 Answers

Where can I find the "insect screen -full width" that is shown in detail 2-00004?

I am using the GBA wall section detail #2-00004. I have been looking online for the insect screen described in the detail. I envision it as something like a soft mesh that is 3/4 thick. Is there anything out there that is not too expensive? If so, who is making it?

In Green products and materials | Asked By Beth Robinson | Jan 6 12
5 Answers

How to build a movable passive solar heat sink?

My wife & I are remodeling a house to accomodate a 133 inch long dining table when fully expanded. Most of the time the table is closed to a 60 inch diameter. We will install a south facing window approx. 7 ft. long x 4 ft. high. Except for when the table is fully expanded (1% of the time), we could have a passive solar heat sink inside the room near the window, but need to move it to accommodate the table when fully expanded. Have been thinking of something water filled. We could install a faucet & drain in the room. A movable sink would also allow it to be unused during the summer.

In PassivHaus | Asked By Robert McDonald | May 24 09
6 Answers

Builder demos porch and sunroom at deadbeat client's home

Patrick McCombe, an editor at Fine Homebuilding, e-mailed me this link to a YouTube video reporting on how one British builder handles deadbeat clients:

In General questions | Asked By Martin Holladay | Jan 5 12
15 Answers

How does flash and batt impact mositure migration?

Does this practice (flash and batt) work with single wall construction where the foam is sprayed against housewrap?

Some builders in the KC metro area use single wall construction. To meet efficiency expectations they are wrapping the home, spraying 1/2" to 1" closed cell foam and filling the cavity with batt insulation. Does this cause issues with moisture migration?

In Energy efficiency and durability | Asked By Bruce Chyka | Jan 4 12
6 Answers

Insulating a framed half-high wall in a basement


We have just completed construction of an addition on our home in zone 5A. The addition has a walk out basement that does not have a heat or a/c duct located in the space. The walls were built with concrete block to above grade (floor to about 38") and then the rest is a 2x6 studded wall (about 58") The wall construction as of now is as follows from outside in. Brick veneer - 2" vent space - OSB sheathing attached to 2x6 stud wall OSB is wrapped with Tyvek on the exterior.

In Energy efficiency and durability | Asked By Martin Miller | Jan 5 12
3 Answers

SIPs Roof Replacement

I have an energy makeover project for a client with an older log home. Beyond the usual infiltration issues we need to repair/upgrade the roof.

Current: asphalt shingle, tar paper, OSB in fair shape -- some rot and rodent damage, but not past fixing.

One plan is to strip back to OSB, repair as needed, add tar paper, 4" SIP Nail board, More tar and paper and a standing-seam metal roof ready for PV.

Thoughts? Ideas? Criticisms?


In Green building techniques | Asked By Bruce Glanville | Jan 4 12
4 Answers

Most effective door weatherstripping?

So, for blocking little air leaks around the perimeter of the door slab: of the typically available options--the felt stuff, the foam tape, the molded plastic fin stuff, the teardrop-shaped stuff, etc.--what's the best plan of attack? What's useless?

I've got some of that typical compression door seal stuff (whatever it's called) installed on the jambs, and there's a triple-seal sweep already installed, but it's not really close to perfect yet.

I'll also be installing it around my vent panel.

For what it's worth, I have indeed looked at this:

In General questions | Asked By Minneapolis Disaster, 6B | Dec 26 11
9 Answers

Reflective barrier and insulation for radiant heat

Hey all, looking for thoughts on my heating upgrade. After reading and reading I think I know enough to ask questions (but not have the right answers) so i figured the voices of experience could help.

I'm in the process of installing radiant heat in my 1,800 sft single level home in Long Island NY. It will be PEX in the joist bays over a crawl space and basement. the crawl space has a concrete floor over a vapor barrier and the basement is unfinished without any underslab/exterior insulation. I'm trying to figure out the best way to insulate so here are my thoughts on the process

In General questions | Asked By Michael schlee | Jan 3 12
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