Insulating hip roof corners

[diggler306]

I'm having my heater hung this Friday so I need to prepare by throwing up some vapour and a half sheet of drywall in the corner. I have a hip roof with a relatively low pitch, making space in the corners preeetty tight. I got to thinking that I should probably insulate and do whatever else in that corner beforehand too.

See attached photo. 2x6 rafters. Cold climate. Should I just stuff as much R22 in the corner without worrying too much about soffit venting? I can't even get an insulation vent baffle in there really. The soffits are vented continuously around the whole garage (24x24), so I'll likely still get plenty of air flow elsewhere without worrying about the corners. My plan was do put in R22 batts in the ceiling, R12 in the walls, and then maybe blow in additional insulation after I put in a small attic floor area for storage.

Thoughts?

 

[firecracker]

I've got the same probblem as you diggler, I just stuffed as much insulation in as pos. think that was about 8" and like you again I have lots of draught blowing in the roof space so no chance of damp appearing.
Mine has lasted 10years up to now.

 

[diggler306]

Thanks firecracker! There's only a few inches between the bottom of the hip/jack rafter and the top of the ceiling joist, so once the drywall is up, i'm likely not getting in there again. If I fill it, I should get about the same amount as you did at it's highest point.

 

[Steve in Mi]

I have a question on the gas line. Will it pass code? In my neck of the woods the only time a natural gas line is permitted in a wall cavity is in the case where it passes thru a wall and there are no fittings/joints allowed in the wall cavity. Maybe you are okay with it by Canadian code but it jumped right out at me as not passable in my location.

I remember cutting some foam roof vents lengthwise to work near the corners but as you say it is tight in the corner. Think I used a broom stick to push fiberglass in any tight spots.

 

[diggler306]

Thanks for the comment Steve. I had the gas line done by a licensed plumber, so I sure hope it's to code, but I guess you never really do know unless you look it up yourself eh. I'll look into it.

 

[rsanter]

Fiberglass insulation only works if it has fluf or loft. Meaning you can't compress it or shove it in or you loose R value very quickly.
The way I see it is you need either rigid foam sheets, blown in expanding foam or blown in loose fill

Bob

 

[Steve in Mi]

Fiberglass insulation only works if it has fluf or loft. Meaning you can't compress it or shove it in or you loose R value very quickly.
The way I see it is you need either rigid foam sheets, blown in expanding foam or blown in loose fill

Bob

Noted but can you picture the fiberglass being pushed thru a small opening fluffing up in the larger space behind. Sort of like compressed batts and roll fiberglass expands when you open/cut the packaging from the manufacturing company.

 

[rsanter]

Noted but can you picture the fiberglass being pushed thru a small opening fluffing up in the larger space behind. Sort of like compressed batts and roll fiberglass expands when you open/cut the packaging from the manufacturing company.

Yes and no. You would need to have the properly trimmed to size and then get them in and fluffed to where they need to be.
In areas that narrow this you will have to thin the insulation to the point it won't do much.
This is the big failing with the install quality of fiberglass insulation.
Can it be done, yes. Usually dosent get done effectively.

The more central areas where access is easier can be done right no problem and the fiberglass will work great
The other thing is that to work properly fiberglass needs 6 sided contact and still air. Just like it sees inside a wall. Best thing for you to do when installing fiberglass in the foor trusses is to install some 1/8th plywood to box it in. This will also give a better finished look, protect the insulation from damage or falling down, and you can paint it for more reflected light

Bob