This is the question we are asked most often, and the honest answer is that it depends on whether the failures are isolated or general. Here is how to work out which you are looking at.
Isolated failures mean repair
A handful of slipped tiles in one area, a cracked ridge, a failed section of flashing: these are events. Something specific happened, or one component wore out. Repair it, and the rest of the roof carries on doing its job. Replacing a whole roof because of three tiles is a waste of money and we will say so.
General failures mean replace
Slates slipping in different places every few months, widespread nail fatigue, felt beneath that has perished across the whole roof, battens that crumble when touched: these are not events, they are age. Repairing them individually becomes an annual cost that never ends, and each visit costs access as well as labour.
The tell is the pattern over time. If you have paid for three separate small repairs in two years and they were all in different places, the roof is telling you something.
The arithmetic worth doing
Compare the cost of a re-roof against the repairs you would realistically expect over the next ten years, and include scaffold or access on each visit, because that is a large share of the cost of a small job. On an ageing roof, replacement frequently comes out cheaper over that period, and you also stop having to think about it.
Get the structure looked at either way
Whichever route you take, the timbers matter. On a re-roof they can be inspected once the covering is off, which is the only time anybody gets a proper look. That is a genuine benefit of replacement that rarely appears on a quote.
Ask for both options
Any roofer worth using should be able to price a repair and a replacement and explain which they would choose for your roof and why. If you are only offered one, ask about the other. We quote both as a matter of course. Call 023 9355 3347.