Contractor Talk - Professional Construction and Remodeling Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
1,716 Posts
Discussion Starter #1
Hi guys, I'm an ex-lurker from south western Canada (mild weather). I'm going to be rebuilding the roof on a house that presently has no eaves or rakes. I'll be putting those on and then roofing. The basic roof is 8/12 gable with two shed dormers, one each side that meet at the peak. They are 2/12. The building is older with minimal insulation at present and NO vapour barrier. I'd like to add ins. when I sister the rafters. Intake venting will be in the new soffits.
How would you guys vent the two sheds? We do get snow here, occasionally a couple of feet, but it only rarely gets much below freezing and that not for long.

I'm planning on torch roofing the sheds, and 30 yr arch. shingle the rest.

Ideas, input, thanks, Rich.
 

·
Commercial Roofing
Joined
·
1,220 Posts
Do not fill the cavity with insulation, so that you can have positive air flow, then you can install one way vents designed for low slope. Have you used torchon materials before?
 

·
Registered
Joined
·
1,716 Posts
Discussion Starter #3
Yeah, I've done torch before, where would you put the vents, who makes them, tks, Rich.
 

·
Commercial Roofing
Joined
·
1,220 Posts
I would put them near the ridge, about a foot or less down from it. Your roofing material house should have one way breathers.
 

·
Registered
Joined
·
174 Posts
You can use the foam "insulation deflectors" to provide an air space above the insulation. Another way is to use rafters that are a few inches taller than the amount of insulation you are adding. Can't you just use a ridge vent instead of the turtle vents?
Jim
 

·
Commercial Roofing
Joined
·
1,220 Posts
My concern with the ridge vent here is the 2/12 slope. Blowing rain and ice would not have much trouble getting in there.
 

·
Registered
Joined
·
1,716 Posts
Discussion Starter #7
We get LOTS of rain. Wouldn't put in a ridge vent on this low of a slope. The roofs are small, all it would take is a couple of turtles if they would vent all the cavities, are you suggesting one per cavity?
"Your roofing material house should have one way breathers." Explain?
How is a low slope vent different from a standard turtle? Rich.
 

·
Commercial Roofing
Joined
·
1,220 Posts
It is a taller conical type vent that stands up off the roof surface. Snow and blowing rain will not infiltrate this type of vent if properly installed.

As far as the rafter cavities, you would definitely not want the insulation to the top of the cavities, but a contiguous air space aboe the ceilings. Keep in mind that you would need quite a few of these vents. Turtle vents are not meant or designed for low slope roofing.

Hope this helps. I will look for more ventilation solutions for you.
 

·
Registered
Joined
·
8,573 Posts
AaronB. said:
My concern with the ridge vent here is the 2/12 slope. Blowing rain and ice would not have much trouble getting in there.
Exactly. Most manufacturers say not to place on less than 3/12.

If it were my shed, I'd use the rafter baffles, aka insulation deflectors, to create that positive air flow from soffit to attic.
 

·
Registered
Joined
·
24 Posts
I might be missing something here,
but unless this house has cathedral ceilings,
the small 6 ft section of 3/12 pitch area,
would not really effect the air flow dynamics,
if the soffit factors and ridge vent openings are
adjusted accordingly. The would still be 28 feet of ridge vent,
and air flow across the ceiling joists doesn't seem to be
blocked, allowing continous airflow above the propa-vent system.

just my $.02 worth
David
 

·
Commercial Roofing
Joined
·
1,220 Posts
builderr, the roof pitch is 2/12. Low slope membrane being applied, not good for ridge vent. Sorry.
 
1 - 12 of 12 Posts
Top