Re insulating attached garage questions

[RumRiver5.0]

Alright let me describe the scene before I ask how to approach this mission! What I have is an attached garage that was already insulated with R11 on the walls and underside of roof. The roof underside has the insulation attached at the supports (joists?) from the top of the wall to the peak. It's old and a bit moldy. The "fire resistant" drywall separating the house and garage has mold above the straight rafter/ceiling height. There were no roof vents or perforated sofitts at this time.


A few years ago I installed a 60k btu furnace up in the rafters and vented it with double wall through the roof. I attached a bracket for a slide in filter and change it out often. It wasn't an expert job by most professional standards but I made it work. We daily drive old cars and I can't afford to pay mechanic to do what I can in reasonable conditions every time something goes wrong in the dead of winter. This furnace has saved the bacon a couple of times for sure.

After some huge storm damage last year I had the roof and siding redone. My "ok" work with respects to the venting were corrected properly along with the suggestion of adding 3 vents for the garage roof. The old insulation is now falling off, garage doesn't hold heat as long due to the vents and this needs to be corrected.

What are the options to get this right? I do like using the ceiling level rafters for storage but perhaps it should go.

 

[The Cobbler]

not sure I understand your post 100%, but do you have insulation up against the roof?
you need airspace between the roof & the insulation as well as venting from the eaves to the roof peak basically
you don't want to insulate between the ceiling joists because you want to use the attic space to store stuff?

 

[RumRiver5.0]

Pretty close to being up against. I was thinking of getting functional airflow by modifying the soffits and putting up thicker insulation as well.

 

[RumRiver5.0]

not sure I understand your post 100%, but do you have insulation up against the roof?
you need airspace between the roof & the insulation as well as venting from the eaves to the roof peak basically
you don't want to insulate between the ceiling joists because you want to use the attic space to store stuff?

I've been told several things. 1) The way it was without heat was incorrect due to having no plastic between the rafters. 2) With heat was going to rot out the roof and now 3) It's losing a lot of heat through the added 3 vents that were included in the roof job.

So I guess I'm looking for the best solution to this mess. Venting properly and keeping heat inside.

The garage is a 2 stall but I want to most efficient setup and if that means closing off the ceiling I will.

I would even add duct work. I just never done this stuff before.

 

[matt_i]

I think easiest solution is to add the ceiling, drop the heater below it.

You can still use the rafters, just have to build in an access opening.

I would try for 10" of insulation above the ceiling, blown-in. Use the truss-ducts so your insulation doesn't cutoff the newfound airflow.