Quick answers
On a leaking metal or corrugated roof, is sealing the joints and screws enough, or does it need a full coating?
If the metal sheets themselves are sound, cleaning and sealing the parapet joint and every screw head is enough. If the whole surface is weathered or overheats in summer, a full reflective coating or sprayed polyurethane foam is applied.
On metal and corrugated sheet roofs, leaks almost always start in two places: at the fixing screws (once their rubber washers perish) and along the junction where the sheets meet a parapet or side wall.
On this red metal roof, the sheets themselves were sound, but the joint along the parapet was full of perished old foam and gaps. The channel was cleaned out completely, refilled, sealed along its full length, and every screw head across the roof was covered individually.
When a corrugated roof is covered in moss and lichen or weathered across its whole surface, it is pressure-washed and either given a full protective elastomeric coating or sprayed with polyurethane foam and a white UV top coat to stop leaks and keep summer heat out.
Jobs that show it
Sealing the Joints of a Metal Roof
On a red metal roof, the joint against the parapet was full of dirt and crumbling foam. It was cleaned out, refilled and sealed, and the screw heads were covered too.
See the job step by stepCoating a Corrugated Roof
A corrugated roof covered in moss and lichen was cleaned and coated in a silvery-white finish that protects it from the weather.
See the job step by step
Spray Foam and a White Coat on a Corrugated Roof
The old roof was washed, sprayed with polyurethane foam and painted white to stand up to the sun.
See the job step by step