Garage insulation / attic venting

[1967Chevelle]

Looking to insulate and properly vent my attic in the garage. The garage block construction with no insulation at all at the moment, the garage is 22' X 24' with a loft, I'm thinking completing the loft floor and placing insulation (R20) and vapor barrier under the loft floor.

Also the soffit is all plywood without any venting currently, I have 2 roof vents (one on each side of roof) just below the ridge,

since I'm going to be insulating the loft floor, would I need to install vents into the soffit? along with Attic Rafter Vents?

 

[NUTTSGT]

It looks like you have a newer hip roof. Having a hip roof doesn't allow the use of gable end vents which are generally easy to put in.

To get air out, you need to get it in after you close off and insulate that ceiling. While it may not be the be form of ventilation, they make some small round vents that you can put in the soffit if it it tight on space. These are 4" but they also make 2 & 3" versions.

https://www.menards.com/main/mcom/b...981946224.htm?tid=4184370840376195215&ipos=72

If you have more room you can get a similar vent that is larger and rectangular.

https://www.menards.com/main/mcom/b...81946224.htm?tid=-8212885480084948810&ipos=11


I'd use either R-19 or R-21 for the ceiling, whatever is available locally to you with kraft paper and cover it with something like ribbed metal. You might lose a few inches of head room but it will brighten the area up.

Once you have that done, you'll still lose heat through the walls. You guys have cold winters up there and those block walls will **** the heat right out. The back wall of my garage is block and it was always cold. I tap-conned 2x4s to the back wall, stuffed in 1.5" polystyrene and covered with 7/16" OSB. It made a huge difference getting and keeping the garage warm.

When I started to vinyl side the garage, the block exterior got firring strips tap-conned on it, stuffed with 3/4" polystyrene, sheathed and vinyl siding on top of that.

 

[1967Chevelle]

It looks like you have a newer hip roof. Having a hip roof doesn't allow the use of gable end vents which are generally easy to put in.

To get air out, you need to get it in after you close off and insulate that ceiling. While it may not be the be form of ventilation, they make some small round vents that you can put in the soffit if it it tight on space. These are 4" but they also make 2 & 3" versions.

https://www.menards.com/main/mcom/b...981946224.htm?tid=4184370840376195215&ipos=72

If you have more room you can get a similar vent that is larger and rectangular.

https://www.menards.com/main/mcom/b...81946224.htm?tid=-8212885480084948810&ipos=11


I'd use either R-19 or R-21 for the ceiling, whatever is available locally to you with kraft paper and cover it with something like ribbed metal. You might lose a few inches of head room but it will brighten the area up.

Once you have that done, you'll still lose heat through the walls. You guys have cold winters up there and those block walls will **** the heat right out. The back wall of my garage is block and it was always cold. I tap-conned 2x4s to the back wall, stuffed in 1.5" polystyrene and covered with 7/16" OSB. It made a huge difference getting and keeping the garage warm.

When I started to vinyl side the garage, the block exterior got firring strips tap-conned on it, stuffed with 3/4" polystyrene, sheathed and vinyl siding on top of that.

how many vents of 4" would I need to add?

 

[biggziff]

how many vents of 4" would I need to add?

https://www.todayshomeowner.com/adding-soffit-vents/

The best venting is ridge and soffit. If you decide to do this, you need to close any gable or other passive venting.

https://www.finehomebuilding.com/2011/07/14/a-crash-course-in-roof-venting