The roof is truss built and the area over the conditioned space will be an unvented conditioned attic insulated with spray foam.
Roof tress covers bedroom and porch insulate.
The insulation should fit snugly to prevent air from getting through.
An insulated aluminum patio roof uses aluminum clad foam panels.
A roof does get hotter than the walls in the summer but doesn t matter at least in colder climates.
Alternatively you can use wire crossed diagonally back and forth between nails to hold it up in place.
If you have a flat garage roof and an attic above you can install the garage insulation from below using a standard ladder.
I have a 28x36 garage with 28ft span 8 12pitch attic trusses.
Cut styrofoam insulation to the correct size and layer it below the fiberglass already in place.
In either case you will need to follow the general steps below to insulate your garage roof.
If the cavity between the rafters trusses is filled with insulation and is air tight like the walls you will need a vapour barrier.
The run or the base number is 12 inches.
The rise will be the elevation change over the 12 inches.
However if you have a cathedral style garage roof you will need a scaffolding to get into the upper areas of the roof.
Large foam insulation sheets can be nailed directly against the floor above or held in place by chicken wire or other metal elements with the facing against the underfloor.
Polystyrene core insulated roof panels great for homes cottages rvs and trailers versatile high quality and ready to assemble aluminum patio cover kits for the handy diy homeowner interested in a clean professional looking finished product at a fraction of the cost from a contractor.
A pan roof has a less finished look with the pan roof sections either corrugated or creased to add rigidity.
The main question is how to handle the attic space over the porches due to the porches being created by the overhanging roof trusses and since the attic is unvented it is not practical to vent the porch attic.
They make the roof panels 3 to 6 inches thick not just at the edges where the fascia on a pan roof may be that tall but all across the panels.
If you can crawl under your porch insulate from below by nailing plywood boards to cover any openings.
The trusses have a 2x10 bottom chord and 2x8 top chords with 2x4 s at the kneewall.
I live in michigan climate zone 5.
A roof is designed to be water tight and properly constructed and maintained it will be.
For example a slope of 6 12 means for every 12 inches of horizontal distance the slope of the roof will rise 6 inches vertically.