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3 Answers

Air barrier behind T&G paneling

We have some T&G paneling that is going to be installed on our walls and ceilings on a house we are building. Understanding that T&G paneling is not an air barrier we have typically installed Sheetrock first and installed our paneling over top the Sheetrock.

Our interior trim salesman says it is better to use OSB or plywood on the wall as sheetrock holds too much moisture and could cause problems with our T&G. He has been selling interior trim for about 30 years so typically trust his opinion.

In Green building techniques | Asked By Danny Kelly | Jan 17 12
5 Answers

Insulating crawlspace in a 200 year old house

We have a project involving a 250 year old house built on the side of hill that, 17000 CFM @50 pascals. The customer does not have a lot of money, so we are trying to figure out the best way to air seal/insulate the crawlspace. When running the blower door, there is noticeable air leakage through the floor boards and along all interior wall bottom plates. The oil furnace is in the crawlspace and although I would like to figure out a way to condition it all, the crawlspace is uneven and broken up by rock walls as part of the foundation, storage areas, and 5 foot high dirt piles.

In Energy efficiency and durability | Asked By Jim Hanson | Jan 16 12
7 Answers

Best practices for air-sealing sheetrock to top & bottom plates?

ENERGY STAR (ES) now requires that gypsum wallboard be caulked to top & bottom plates to reduce air movement from conditioned spaces to unconditioned spaces such as unconditioned attics. What are some of the products and practices employed by builders to satisfy this requirement?

In Green building techniques | Asked By Steve Vollstedt | Dec 1 11
6 Answers

Okay to use Open Cell foam over existing batt insulation or foam board? I'm located in Zone 5a.

I have a bonus room that has accessible 3 walls and the ceiling. The room is already insulated on the walls with R-11 and R-3 foam board. I have had two contractors now tell me that they can spray over the existing insulation with open cell foam vs. removing it. I'm curious as to why it wouldn't be better just to remove all the existing insulation [wall and ceiling], spray foam the back of the drywall between the studs; and then put back up the R-3 foam board on the walls and batt insulation up on the ceiling?

In General questions | Asked By Don Pearson | Jan 16 12
3 Answers

Duct heater required with an HRV in a cold climate??

I'm in the beginning stages of building a super-insulated house near Ottawa, Canada. The foundation is completed and we're about to start framing. One of the last details / sub-contractsI need to tie up is the HRV system. One of the firms providing a quote insists a 1500-2000w duct heater is required.

I recognize that the fresh air is likely to be somewhat cooler than the temperature of the house. However, this suggestions a little over-the-top given that the house will have R50 walls, R80 attic, tripled-glazed fibreglass windows and will be tight at less than 1.0 ACH50.

In Mechanicals | Asked By John Scime | Jan 16 12
3 Answers

Is it worthwhile preheating the cold water supplying a domestic water heater?

I will be building a new home this year in northern Ontario, Canada. The intention is to build a very efficient home with high insulation levels. While I have the design essentially complete I still have not determined how to heat my house. The house will be south facing on a slab with a second storey, I am leaning towards radiant heat. Infloor on the main and radiant baseboards on the 2nd floor.

In Mechanicals | Asked By Jody Brinkman | Jan 13 12
5 Answers

Wondering about best (cold climate) strategies for insulating a floor system built on a pier foundation

I poured a pier foundation for a wrap-around covered porch for my house in Vermont last year. Due to changing circumstances we've decided to add-on to our living space by enclosing and insulating this space rather than building the porch. I'm wondering about best strategies for insulating the floor system over the piers. Thanks!

In GBA Pro help | Asked By Micah Whitman | Jan 16 12
2 Answers

Retrofit help

I've been asked to design an attic remodel for client's 1950's Cape on Boston's North Shore. Presently the attic is unfinished and unheated. She wants a new roof, siding and windows, a golden opportunity to try a DER. Also, she would like gabled dormers on the front and a shed dormer in back to increase headroom and furnishing flexibility.

Since so much of the roof will be modified, and the existing rafters are 2x6 @ 16" o.c., the entire roof - structure and all - will be removed, affording some serious opportunities to optimize insulation as well as air and water barriers.

In GBA Pro help | Asked By John Rockwell | Jan 16 12
4 Answers

Does adding 2" polyiso to the interior of an unvented cathedral roof assembly cause any problems?

I am building a new home with cathedral ceilings in a cold climate (zone 6) and have a question about the roof assembly. The plans from the architect call for a 2x12 rafter furred with ripped 2x6, giving a rafter depth of about 14". My builder is uncomfortable with the connection of the furred 2x3 to the rafter and has suggested an alternative. He has proposed skipping the furred strip and just go with the 2x12 rafter and then use 2" foam and apply that to the inside of the rafter. The foam could be installed before the cellulose and then the cellulose could be pumped in behind it.

In Green building techniques | Asked By Geoff Simonds | Jan 16 12
2 Answers

Closed cell spray foam under roofing

Can one apply closed cell spray on insulation directly to the underside of roofing sheeting to which asphalt shingles are nailed to create a cathedral ceiling? I am looking to create a heated loft above a garage with a gambrel roof.

In Energy efficiency and durability | Asked By Terry Kittle | Jan 16 12
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