Insulate the garage...roof.

[Moomin]

Hello.
The plan to insulate my garage is starting to take shape, but the question is what to do with the ceiling. See attached image...this is how it looks today.
The roof beam is 170mm...
My plan is...After trying to find the right way...
Install slightly lower insulation, like 145 for the air gap, and also open up at the eaves so that air can come in. (No opening today).
Put on plastic...and then batten (sparse panel) the ceiling and then put on sheets....

Or do you have another approach??

 

[huggan]

Are you going to have heating year-round?

 

[Moomin]

Well...yeah...but like 15 degrees in winter...and whatever it is in summer...

 

[corre]

Don't forget sheets for the air gap, either masonite or treated corrugated cardboard sheets. The corrugated cardboard sheets can be fastened with a staple gun, for example.

 

[Moomin]

But then I've understood it right to open at the ends, and then create the air gap, insulate, etc...

 

[corre]

Are you going to fill the joints in the ceiling and paint?
I suspect that the current ceiling joists are not sized with the deflection factor in mind. So there is some risk that it will crack because of that.

Otherwise, as I understand, it's a correct way to insulate, albeit not very efficiently.
But if you maintain 10c and support with an electric fan when you work, it probably doesn't matter that much.

 

[Moomin]

Corre: Yes, that's the idea in the longer term, whether it will be boards or just råspånt remains to be seen. Today it's not insulated at all above, just tar paper and boards... so there's no point in even heating it.
But the thought is, as you say, to keep it at 10-15 and then use a heater when I'm going to work there...

Thanks for the input... now it's time to prepare insulation.