Signs you need a new roof (and when a repair will do)

Signs that point to replacement

• Multiple or recurring leaks. One isolated leak is often a repair. Several leak points, or leaks that keep coming back, usually mean the underlay (felt) beneath the tiles has failed.
• Sagging. A dip or wave in the roofline can indicate a structural or timber problem and should be looked at promptly.
• Widespread missing, slipped or cracked tiles. When more than roughly a quarter to a third of the covering is damaged, replacement often makes more sense than endless repairs.
• Daylight or debris in the loft. Light coming through, or bits of felt and mortar dropping through the battens, suggests the underlay and fixings are past their life.
• Age. Concrete tile roofs typically last 40–60 years, clay 60–100, slate 80–100+. Felt flat roofs much less. A roof well past its design life is living on borrowed time.
• Failed flashings. Lead flashing around chimneys and abutments can fail before the tiles do and is a common leak source.

When a repair is the sensible call

A few cracked or slipped tiles, a single localised leak, or worn ridge mortar are usually repairs, not replacements. A rough rule of thumb used in the trade: when repair costs start approaching 35–40% of a full replacement, replacement is often the better long-term value. A roofer's inspection (typically £100–£250) before you decide is money well spent.

What to do next

If you're seeing several of these signs, get a proper look from a qualified roofer before water gets into the timbers — the longer a failing roof is left, the more the repair bill grows. You can get an indicative replacement cost from our calculator first, so you know roughly what you're budgeting for.