New shed roof covering

Has there been any accommodation made for, or damages resulting from, differential expansion?

That's one concern I would have about a metal covering on a wooden shed.

When cutting, they suggest using shears, which smears the galv over to protect the cut edge. Drilled holes are in the bottom of the channel, and fitted with self sealing tec bolts. I have no sign of any rust at all, after maybe 15 years.

I made no provision, and never had a problem.

The only issue, has been that a very few of the tec bolt plastic caps, have blown off. Next time, might be worth adding a blob of silicon sealer, or stick like... under the cap, to make sure they stay put.

Warehousing, farm buildings etc. use acres of the stuff without problems.

I tend to fit the double skin insulated version in anticipation of eventual farm building conversion to business use requiring heating. They *creak* with exposure to changes in sunlight!

An unexpected issue I reported here a couple of years back is the

Edge rusting might be encouraged by angle grinder trimming but snips are a pain. I asked one of the manufacturers how they trimmed the undersheet to create a *drip* and was told they use a metal cutting circular saw.