Chicago Garage roof insulation

[chiGarageGuy]

I had a detached garage built this summer in Chicago and figured I'd do the insulation myself after to save a few bucks. Now I'm running into some issues with how to do it the right way. I insulated the main walls with faced batt. Now I need to decide how to do the ceiling/peaks of the walls.

I have 4 square roof vents and aluminum soffits that are vented. Will closed/open cell matter for that? Does the insulation company need to vent with baffles the insulation if sprayed into the 2x6s?

If I batt the roof, do I need to use rafter vent baffles? Do I use them in each rafter and the entire length of the rafter?

The peaks of the walls on the A frame sides are not framed out like the bottoms. Should I just frame them for batts/drywall or spray foam them? If I spray foam them I run the issue of not being able to cover them down the road with osb/drywall

I attached pictures of what I'm working with. Thanks

 

[Kaizen]

The end walls below the mini ceiling need to be firred out for same insulation as bottom. Also measure to see if those are 24 or 16 spacing.
That garage was designed to have the attic sealed And each bay vented up into that sealed space. So yes baffles in each bay up into the attic. Closed cell is the best but most expensive. What size wall studs do you have?


Sent from my iPhone using Tapatalk

 

[Showkey]

Add ceiling joist or supports and put a ceiling in the garage.
Insulate the ceiling just like the home. Ceiling could be wood, metal or drywall.
Insulation could blown in cellulose or fiberglass batts or Blown
Leaving the vents open in the roof.

https://www.diynetwork.com/how-to/r...ceilings/how-to-install-fiberglass-insulation



For price spray foam .........ceiling install and insulation will still much cheaper.
Spray foam will still need to covered per code.

 

[chiGarageGuy]

The end walls below the mini ceiling need to be firred out for same insulation as bottom. Also measure to see if those are 24 or 16 spacing.
That garage was designed to have the attic sealed And each bay vented up into that sealed space. So yes baffles in each bay up into the attic. Closed cell is the best but most expensive. What size wall studs do you have?


Sent from my iPhone using Tapatalk

Wall studs are 2x4 16" on center.
Ceiling is not an option for me as one bay has cathedral ceilings with no rafters for allowing a car lift. The other two bays have loft storage.

If I have open or closed cell foam installed for the tops of the side walls and the ceiling, would they just seal off the ventilator? Is that okay?

I decided to just install 2x4's every 24" to the tops of the side walls in case I ever decide to drywall or osb it..

 

[yeldogt]

Foam would go on the roof deck -- seal the whole thing ... no vents.

Old school thinking has attic vents because fiberglass insulation allows lots of air movement and ceilings leak .... other dense insulation has less air movement ... but still leaks. The theory is by venting -- this heat will leave the building and not heat the roof in the winter w/ snow causing ice dams. Also -- leaking air from dwelling carries moisture with it --- theory goes -- this moisture containing air can condense on the roof deck w/o vents.

Finally there have been studies showing how much moisture vents bring into a structure .... the key is to seal the ceiling .... or foam.

I never do vented attic's in my mid-atlantic climate

 

[Kaizen]

From that info you have no choice but to get foam and block off the vents. No need for any venting. Put plywood over the vents before spraying. Gonna be a big bill


Sent from my iPhone using Tapatalk