Saturday, February 20, 2010

MAISON COCAGNE HOUSE - Roof @ Attics Details



Roof trusses at attic (north) wall are parallel chord trusses to allow for 18 inches of glass fiber batt insulation (R60). The roof trusses are installed at 16 inches on center in line with wall studs below. 6-mil vapor barrier is attached to the bottom chord of the truss. Gypsum wallboard or other desired finish is attached to the truss chords on 1x4 furring strips at 16 inch on center perpendicular to the trusses.

The benefits of installing radiant barriers are still in question. If used, I would recommend attaching the radiant barrier taping all joints to the bottom chord of the trusses after installing the vapor barrier, but prior to installation of the furring strips.

Roofing material is TRACC Moderne Slate roof shingles over ice shield underlayment. This is a 50-year roofing material made locally from recycled materials capable of withstanding a 175 mph wind driven rain. This is a very important feature on the Northumberland Strait where northeasters are not uncommon. The roofing sheds snow easily so consideration must be given to sliding snow in our climate. The roofing also works well for a rainwater collection system (guttering not shown).

Maison Cocagne House is designed with double 2x4 insulated, exterior stud walls separated by a 3-1/2 inch fully insulated space to isolate the exterior walls from thermal bridging. The outside double stud walls would be erected prior to construction and erection of the interior stud walls. The inside stud walls are designed to be load bearing while the outside stud walls are designed to carry the exterior finish. The cold side of the inside stud wall is completely covered in a 6 mil vapor barrier then sheathed with 1/2 inch CDX plywood sheathing to provide lateral bracing as well as protect the vapor barrier. Red dashed line shows location of the 6-mil vapor barrier in the wall system. Red dots show locations where barrier is sealed with acoustical caulking. Experience has shown that the vapor barrier can be safely installed inside the wall as long as 2/3 of the insulation is on the cold side of the barrier. Locating the vapor barrier at the cold side of the inside stud wall allows for installation of electric without penetrating the vapor barrier. The cold side of the outside stud wall is sheathed with 1/2 inch fiberboard sheathing, then covered with house wrap. The design allows for the walls to be framed and insulated on the floors and lifted in place using wall jacks. A perimeter truss with 2x4 vertical blocking in line with the 2x4 wall studs above and below is required to carry the loads to the foundation. Details for optional balloon framing and openings are provided in the links and will be discussed later.

4 comments:

Ellard Martin said...

Very interesting. It looks very complicated and highly technical. Are you familiar with thermal insulators? Does this provide heat recovery ventilator to supply fresh air?
By the way, here's a link for NY Roofing Company for readers or bloggers who have roofing problems.

Ellard Martin said...

Very interesting. It looks very complicated and highly technical. Are you familiar with thermal insulators? Does this provide heat recovery ventilator to supply fresh air?
By the way, here's a link for New York Roofing Company for readers or bloggers who have roofing problems.

Sarah said...

Nice information shared here on roofing. Roofing is the important part to be concentrate more in a building. Recently I have hired a Roofing services for my building from Oklahoma's Roofing Company.

rocky said...

Excellent post,
Its a very useful and good informative post for me. Air which comes through the openings of the buildings gets heated and circulates in the atmosphere with dusts and gaseous particles. It never gets out of the workplace. You have to do something to push it outside.
Thanks for this great sharing.
air ventilator