Push up on the plywood until the foam is touching the roof decking s underside.
Raising sagging roof rafters.
Sagging rafters may be the result of having framed the roof with lumber of dimensions smaller than current building standards such as using 2x4s or 2x6 s or there may be damage to the framing from insects or rot.
Drill holes in angle iron.
If the damage is identified then it will be easy to repair it.
Place a fascia board up under the roof sheathing and nail it with a hammer across the ends of the rafters to strengthen them.
How to straighten sagging roof rafters.
You may find that.
The first and foremost step is to find out how many and from where the rafters are sagging.
Keep the plywood in place using a piece of lumbar strapping until you can get a roofing expert to repair it.
Place the plywood and styrofoam side up against the damaged roof decking.
Remove the chisel and wet the crack with a wet rag.
Actuate the intensity of damage.
The first step is to find out how many rafters are sagging and if anything else is damaged.
Spread polyurethane glue into the crack with a stiff bristle brush.
So you should start by inspecting the roof from the under side or attic.