Female “project manager” for her small retirement home with a tall ceiling needs help please,
First, I want to thank everyone who contributes to this forum as I am learning a great deal. I have read everything I can about Cathedral ceilings and find myself needing to understand more.
I live in zone 6 in CNY.
The structure I am building is a 26×30 “Mountain/Lake/Chalet style” home with 8-foot walls and an 8/12-pitch roof. The south wall contains 4 casement windows and matching geometric windows above. Anderson 400 series. It will sit on a full basement ICF foundation.
The interior is open concept. The only room having 4 walls and an 8 foot ceiling is the Bathroom which is 8 x 10 which creates a small “loft” above. There is one other wall that is only 8 feet tall and separates the kitchen from the bedroom area. My builder tells me the ceilings will be about 15.5 feet and they will be 8 Inch tongue and groove pine. Sigh. I used to be so excited.
I will be installing a wood furnace in the basement. The chimney is in the center of the house and will exit alongside the ridge beam at the peak. We will heat primarily with wood and have a backup propane furnace.
I have engineered plans, for 2 x 12 rafters 16″ OC. These plans call for 5/8 CDX plywood, a “proper styrofoam baffle” and r49 insulation. the remainder of the house is 2×6 construction also 16″oc. My engineered plans are bare bones without much detail. Enough to serve as “plans” and the engineer is not very interested in assisting me with questions.
My code officer let me know that the u factor of the windows I have ordered and the small sq footage allows my roof insulation to lower to r38 and wall to r21.
My builder would like to do the following and I am unsure what to think of his suggestion.
I would like to list the layers for you from the outside of the roof down to the inside of the house where the T&G is attached to see if anyone here would be willing to comment on this idea and offer input.
The roof will have Vented soffits and a 1 ” gap on either side of the peak with a vented ridge cap. The layers from the outside in are as follows:
*26 gauge metal roof (not standing seam)
*1×4 firring 2′ oc horizontally
*Rfoil as a synthetic underlayment (sigh)
*2 rows of ice and water shield at the eaves (to create 6′ wide)
on top of 5/8 CDX plywood (call to engineer, he insists it should be plywood, no reason given)
*Accuvent baffle system for cathedral ceilings from the top rail (it bends down into that area and attaches eliminating blocking so I am told) to the peak of the roof.
*Owens corning R38C faced fiberglass insulation high density 9.5″ thick batt
*Tyvek house wrap to fully cover ceiling (taped I assume) as an air barrier *Tounge and groove pine attached to rafter bottoms
The code officer will allow it and says that it will satisfy a class 2 vapor barrier (kraft facing) and also an air barrier (Tyvek house wrap) and would pass the door blower test)
There will be NO canned lights in the ceiling. ( well…there were but after reading here I decided against it.)
Today I talked with a rep from Huber products about zip board for roofing material. His opinion of the above was that if we used zip board instead of CDX and as long as there was air movement under the roof above the decking and below the roof from the eave soffit to the ridge vent, provided by the accuvent baffles, we would have adequate ventilation to deal with any moisture that would escape into the cavity. He said the faced insulation does indeed satisfy the requirement for the class 2 vapor barrier, and he thought that using the Tyvek house wrap instead of drywall was unconventional but would work as an air barrier and save quite a bit of money and time.
Foundation work starts in November and the builder starts Mid Feb.
I am very grateful to the builder as it has been incredibly difficult in my area to find someone who isn’t booked out for the next 18 months. I want to trust him, and I want to get along with the building code officer, but I also don’t want a bad ceiling in my small little dream house.
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