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2 Answers

Kneewall insulation question

I have been diligently air sealing the home we are building. Extreme air sealing probably, but that’s ok – the only time it is taking is mine and I don’t really cost me any money.

I am getting much closer to actually insulating the home with dense-packed cellulose behind a smart membrane (Intello Plus, in this case) and I have a few questions about some tricky areas. I’ve got some photos and will try to explain the situation adequately.

Asked By Lucy Foxworth | Oct 16 13
4 Answers

Open cell vs closed cell

I am renovating my daughter's room located on the second floor of the house. I got a estimate from a spray foam company. They recommended 6 inch open cell in between my ceiling 2x8 rafters. On the west side exterior wall with a brick wall in the center of the wood frame (chimney) they want to apply 3 inch closed spray foam in 2x4 wall. I believe I am in zone 4a. My question is: is the open cell the right product and do I need a vapor barrier?

5 Answers

Exterior siding details

My house is a 1500 square ft bungalow located on Lake of the Woods in Ontario near the Minnesota border (Climate Zone 7) . Before I purchased the house the previous owners replaced all the windows with triple pane pane windows but had the installers build them out 1.5" with intentions of adding exterior foam when the siding was to be replaced. I have since gutted the entire main floor and rewired, plumbed and insulated with 3.5" of closed cell spray foam in the walls. I added a couple more windows and a set of patio doors and stuck with the 1.5" build out.

Asked By JP Patrick | Oct 2 13
3 Answers

Fiberglass-clad sheetrock as vapor retarder?

I live in IRC zone 5A Pennsylvania. I’m insulating the walls of my kitchen; it was gutted to redo the wiring and the plumbing. There are two exterior walls a north and south side an uninsulated garage on the east side and the main house on the west side.
The exterior walls are clad with vinyl siding over house wrap. The corners of the kitchen are sheathed with ¾ inch plywood –the rest is clad with ¾ polyisocyanurate (PIR). The framing is 2x6, 16 inches OC.

Asked By Anthony Jackson | Oct 1 13
1 Answer

Pre-existing unvented cathedral ceiling-- will there be problems?

My client has a house built in the 1970s with cathedral ceilings, a shallow (2 in 12) roof, 2x12 rafters, and T&G pine ceiling. The ceiling was insulated (looks like R-38 faced batts), but there is neither ridge nor soffet venting. The owner had a membrane roof put on about 2 years ago and now wants to remodel. I am concerned about an unvented roof with a relatively "leaky" ceiling-- won't there be issues with moist air getting into rafter space and condensing on the underside of the roof deck?

Asked By cynthia sharon | Sep 25 13
3 Answers

Cathedral ceiling technique explained?


I posted a full description in the insulation and energy forum, but I am also looking for the building details for the unvented cathedral as seen on page 68 of the article posted below. The #3 Unvented roof. We are in the SF Bay area.

My roof has 6x10 beams, covered by 1 1/2" T&G. In the re roof, this will get sheathed with plywood, then I'll add two to three layers of 2" polyiso. I am hoping for 2 layers to save money. Will that give me a true R30? I thought it was only R 6.5 per inch. On top of that will be another layer of 1/2 ply.

Asked By R W | Sep 22 13
2 Answers

How to finish out stem wall?


I have looked through just about every foundation wall detail and I have yet to see one like the one spec'd for my remodel. I'm curious the best way to finish this out as the concrete stem wall is only partially up the wall. This is a stem wall on a slab on grade that only goes up the bottom 8 inches or so of the walls of what will be bedrooms.

I believe the architect just wants to fur it out and put drywall over that. We are in the sf bay area.

I've attached the detail below.

Asked By R W | Sep 21 13
8 Answers

Cardboard insulation baffles

Wondering if there are any drawbacks/issues with using cardboard ventilation baffles? We made our own baffles out of foam sheathing for the last two homes we built to create an air tight insulation cavity between rafters. Needless to say it is a very time consuming and costly process, especially with a few volume ceilings.

We just experimented making baffles out of a sheet of cardboard and we think we could create, install, and seal these cardboard baffles in a fraction of the time it would take with other materials.

Asked By Bruce Miller | Mar 31 13
6 Answers

Boiler cycling on and off with a low-flow shower head

Just wondering if anyone has come across this before. I have a Baxi Luna 310 fi modulating boiler for both in-floor heating & domestic hot water (35,000-105,000 Btu). With a low-flow shower head (approx. 6 litres / minute), the shower water goes from hot to cold constantly. I noticed the boiler cycles on and off the same way. The boiler requires a minimum flow rate of 11 litres / minute to prevent it from cycling on and off.

Asked By bert matter | Sep 16 13
2 Answers

Siding/insulation/WRB/drainage etc. -- shorter question


I have a question with somewhat less detail than my last volley :)

I am building a new house 100 yards from the ocean - elevated approximately 10' off grade. fiber cement siding

Connecticut shore - 4+ or 5- mix of humid/warm and first cold zone = maybe 40 rain days... near water - driving rain elevated (somewhat protected by large eaves and gable end over hangs). right on the edge of both zones.

Specs - as they stand right now. Still a few weeks out (can easily change up to application for building permit). From inside out:

Asked By pat rowland | Sep 10 13
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