Should I Repair or ReplaceMy Roof?

Repair or Replace: How to Decide

It's the question every homeowner with an ageing roof faces, and the honest answer is: it depends on three things — how much of the roof has actually failed, how old the covering is relative to its expected life, and whether the structure beneath is sound. Get those three straight and the decision usually makes itself.

The temptation is to think in terms of age alone — "the roof's a hundred years old, it must need replacing." That's often wrong. Brighton is full of Regency and Victorian roofs well over a century old that are performing on their original slate, needing only their nails and lead renewed. Equally, a concrete-tile estate roof half that age can be comprehensively finished. Condition, proportion of failure, and roof type decide it — not the calendar.

Age and Condition by Brighton Stock Era

Every roof covering has an expected service life, and where your roof sits against that life is the starting point. In Brighton's housing:

• Regency & early Victorian (Welsh slate), 80–100+ years: Brunswick, Kemp Town, Montpelier. Frequently original and sound — failures are usually nail sickness and lead, both repairable. Replacement rarely justified on age alone.
• Victorian & Edwardian (clay tile & slate), 60–100 years: Hanover, Fiveways, Preston Park. Many at the point where selective repair or partial renewal beats full replacement, depending on condition.
• Inter-war & post-war (concrete tile), 30–50 years: Moulsecoomb, Whitehawk, Saltdean, Peacehaven. These are the roofs most often genuinely at end of life — concrete tiles carbonate and become brittle, and nail sickness spreads across whole slopes.
• Flat roofs (felt/GRP/EPDM), 15–25+ years: extensions citywide. Felt at 20 years is usually replacement; GRP and EPDM last longer and can sometimes be refurbished.

Brighton's coastal exposure pushes the lower-life coverings toward the shorter end of their range — salt air and wind uplift are unkind to concrete tile and felt in particular. That's a factor in the decision and a reason coastal-grade specification matters on any replacement.

The 30% Rule of Thumb

Roofers have a working rule: once more than about a third of the covering has failed or is actively failing, patch repairs stop making economic sense. The reason is access. Every repair visit carries the cost of getting safely to the roof — towers, ladders or scaffold. When failure is localised, that access cost is spread over a genuine fix. When the roof is giving out generally, you're paying that access cost again and again to chase failures that keep appearing elsewhere, and the running total overtakes the cost of replacing the roof once, properly.

Under roughly 30% failure with a sound structure, targeted repair is almost always right and replacement is oversell. Over it — especially with repeated leaks in different places — replacement usually wins. The figure isn't a law of physics; it's a practical threshold, and a good survey applies judgement around it rather than treating it as a hard line.

Cost-Per-Remaining-Year: The Honest Maths

The most useful way to compare repair and replacement is cost per remaining year of roof life. A £600 repair that buys three more years before the next problem costs £200 a year. A £7,000 re-roof that lasts sixty years costs a little over £100 a year — and gives you six decades without another roofing bill. Framed that way, replacement of a genuinely spent roof is often the cheaper choice over time, even though the upfront number is larger.

But the maths cuts both ways, and this is where honesty matters. If your period slate roof needs £1,200 of re-nailing and re-leading and will then give you another thirty years, that's £40 a year — and spending £12,000 to replace it would be spending money to shorten, not extend, the value you get. We do this calculation with you at survey, using your roof's real condition and remaining life, so the decision rests on figures rather than a sales pitch.

When Replacement Is Oversell

A full re-roof is the biggest-ticket job a roofer can sell, which is exactly why it's the one most often oversold. Be cautious of a replacement quote when:

• the roof is a sound period slate roof with only nail sickness or failed lead — that's a repair, sometimes a partial re-slate, not a re-roof;
• the roofer can't show you widespread covering failure — photos of a few slipped tiles don't justify replacing the lot;
• there's no structural problem and no sagging, and the leaks trace to specific, repairable junctions;
• the quote arrives from a doorstep caller who "noticed" your roof — the classic overselling entry point.

Our position is simple: we recommend replacement only when a survey can show you the roof genuinely needs it. If it doesn't, we'll tell you, repair it, and leave you with a roof that has years left and money still in your pocket. If you've been quoted a re-roof and it doesn't sit right, get a second opinion — our survey and honest view are free.

Applying It to Your Brighton Roof

Brought together, the Brighton picture is this. On the Regency and Victorian slate of Brunswick, Kemp Town, Montpelier and Hanover, the default is repair — these roofs are built to last a century-plus, and their typical failures (nails, lead, individual slates) are repairable; replacement is the exception, justified only by genuine widespread delamination or structural failure. On the post-war concrete-tile estates of Moulsecoomb, Whitehawk, Saltdean and Peacehaven, replacement is far more often the right call — these roofs reach a genuine end of life at 30–50 years, and coastal exposure gets them there sooner.

Wherever your roof sits, the decision should rest on a proper survey — a look at the whole roof at height, an honest assessment of the proportion failed and the remaining life by element, and the cost-per-year maths done transparently with you. That survey is free, and it will tell you honestly whether you're looking at a repair or a replacement. Then you decide, with the full picture and no pressure.

Read alongside this guide: our roof repairs, roof replacement and roof inspection pages, and our new roof cost guide for current Brighton replacement pricing.