Thats why people use the ceramic deck screws.
Insulating a metal porch roof.
Ya the new pressure treated wood they took out arsnic and added more copper will eat through any metal.
If you are experiencing mold and mildew growth damp spots on your ceilings and walls or musty odors there is a good chance that your metal roof is not properly insulated.
The batts are located side to side on the rafter of the roof.
Insulating a new metal roof step 1 install plywood or oriented strand board osb to act as structural roof sheathing.
This in turn prevents moisture condensation on the metal roof.
If you re willing to invest some more consider an insulated porch roof.
Metal roof insulation increases the temperature of the inside surface of the ceiling.
Condensation can cause your ceiling to rot.
The foil will reflect the heat from the roof and the foam will keep any cool air down you will also be able to keep the airspace which is absolutely essential with the steel roofing.
The insulation should fit snugly to prevent air from getting through.
Lay the plywood perpendicular to the roof joists and fasten it in place using galvanized or stainless steel roofing nails.
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.
Both materials make a great physical barrier between the interior building and the metal roof.
Fiberglass batts or glass mineral wool metal roof insulation the most common material used for an insulating metal roof is fiberglass batts or glass mineral wool.
This is different from the normal roll up type of insulation as it comes in panels rather than paper covered fiberglass.