How the lean is worked out
It comes down to whether the roofing itself is sound. Worn mortar, faded paint, moss and the odd broken tile are what a restoration fixes. Tiles crumbling everywhere or sheets rusted through mean the roof is at the end of its life, and paint won't change that.
Cement sheet roofs on older homes are a separate case, because they may be asbestos. That always needs checking first.
What to do with the answer
Use it to frame the conversation with a roofer, not to make the call yourself. Ask them to photograph what they find, and if it's close, ask for both prices. Our guide to restoration vs replacement goes deeper.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.