Repair or Replace? The Question Most Horsham Homeowners Get Wrong

Most people assume their roof needs replacing when a tile slips or a small leak appears. Usually, it doesn't — a straightforward repair will do the job for another decade. But there are situations where repair becomes uneconomical, and recognising them early saves money in the long run. Here are the seven signs we look for when advising Horsham homeowners on whether to repair or replace.

1. Your Roof Is Over 30–40 Years Old

Concrete interlocking tiles — the material used on most of the 1960s–80s estates across Roffey, Littlehaven and Broadbridge Heath — have a design life of roughly 40–60 years. After 30–40 years, they begin to absorb more water, lose surface aggregate, and the nails fixing them to the battens corrode. If your Horsham property was built between 1960 and 1985 and has the original roof covering, it's worth having it surveyed regardless of whether it's actively leaking.

2. Tiles Are Slipping Regularly

A single slipped tile after a storm is a repair job. If you're having tiles replaced every year — or you notice multiple slipped tiles in the same area — that's a sign of widespread nail failure rather than isolated damage. This is the classic presentation of nail sickness, common across Horsham's 1970s concrete tile estates. Replacing individual tiles on a roof with failing nails is a temporary measure; the rest will follow.

Nail Sickness in Horsham

Nail sickness is widespread on the concrete interlocking tile roofs across Roffey and Littlehaven. Read our full guide to nail sickness to understand whether your roof is affected.

3. The Felt Beneath the Tiles Has Failed

Roofing felt is the secondary barrier beneath your tiles — it catches any water that gets past the tile surface. Felt installed before the 1980s is typically a bitumen-based material with a finite life. When it fails, it splits, sags and eventually allows water into the roof structure. You'll often see it as a series of dark stains in the loft directly below the roof slope, or as daylight visible through gaps in the felt when viewed from inside the loft on a bright day.

4. You Have Daylight in Your Loft

On a sunny day, go into your loft and let your eyes adjust to the dark. Any points of light visible through the roof covering — other than at the ridge or eaves ventilation — indicate gaps that need addressing. Multiple light points scattered across the slope suggest the tile coverage has broken down rather than a single tile having slipped.

5. Your Energy Bills Have Risen Unexpectedly

A failing roof covering allows cold air into the roof void, which increases heat loss through the ceiling below. If your heating bills have risen without any obvious explanation and your loft insulation appears intact, the roof covering is worth checking. This is more noticeable in Horsham's older properties where the loft space is uninsulated at rafter level.

6. The Roof Has Multiple Patches From Previous Repairs

A roof that has had repeated patching over the years — different tile types, varied mortar colours on the ridge, mismatched slates — is a roof that has been maintained beyond its natural life. Each repair adds cost; at some point the cumulative spend exceeds the cost of a clean replacement. If a surveyor or roofer points out three or more distinct repair areas, the economics of replacement usually become compelling.

7. Water Staining on Interior Walls or Ceilings

This one seems obvious but is often attributed to condensation or plumbing rather than the roof. The key distinction: roof-related damp appears after heavy rain, tracks downward from ceiling level, and often has a distinctive tide-mark ring as it dries. It's most likely to appear on top-floor ceilings, around chimney breasts, and at the junction of flat roofs and the main pitched roof — all classic problem areas on Horsham properties.

What To Do Next

If one or two of these apply, a repair survey will clarify whether a targeted fix is still the right answer. If three or more apply, replacement is likely the more economical route and we'll tell you so clearly when we survey. We don't recommend replacement when repair will do the job — it's not in our interest to oversell work that isn't needed.

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Last reviewed: July 2026 by Horsham Roofing Experts.