Guide · Roof Repairs

10 Signs You Need a New Roof (Not Just a Repair)

Most roofs we attend can be repaired. But there's a tipping point where patching is throwing money at a roof that needs replacing. Here are the 10 signs we use to call it.

Last updated: May 2026 · By Jamie Pocock

Quick Answer

The 10 signs in order of severity

1. Daylight visible through the roof from inside the loft

Stand in the loft on a sunny day with the loft light off. If you can see pinpricks of daylight, water can get in. Isolated holes can be patched; widespread daylight means the underfelt has failed and the roof needs stripping.

2. Visible sag in the roof line

Look at the ridge line from the street. A perfectly straight ridge is normal; a dip or wave means structural deflection — usually rotted rafters, undersized timbers or failed purlins. Structural sag is a replacement, not a repair.

3. More than 25% of tiles slipped, cracked or missing

1–5 slipped tiles? Repair. A whole face of the roof showing slippage means nail fatigue is widespread (typical on roofs 60+ years old) and individual fixes will keep coming back as new tiles slip month after month.

4. Multiple leak positions in different rooms

One leak in one position usually traces to one defect. Three leaks in three rooms means the roof system is failing as a whole — patching each location costs more than a strip-and-relay over 12–24 months.

5. Concrete tile roof over 50 years old

Marley and Redland concrete interlocking tiles laid 1955–1975 — most post-war UK housing — have a 50–60 year service life. Most are now in or past that window. Symptoms: spalling tile faces, sagging ridges, soft underfelt below.

6. Underfelt visible and degraded

Look up at the felt from inside the loft. Original 1960s/70s bitumen felt that's brittle, crumbling or has visible holes is past end-of-life. Underfelt is the secondary water barrier — when it fails, every minor tile slip becomes a leak.

7. Heavy moss with lifted tiles

Moss itself is treatable. Moss thick enough to physically lift tiles off the battens is a sign that the bedding mortar has failed and tiles are no longer mechanically secured. Re-bedding all tiles often costs as much as a partial re-roof.

8. Perished mortar on every ridge and verge

Isolated ridge mortar failure is a repair. Mortar perished across every ridge tile, verge and hip is a sign the whole bedding system has reached end of life — usually paired with tile slippage on the same roof.

9. Insulation in the loft permanently damp

Damp insulation means water has been getting in repeatedly, not in single events. Wet insulation also loses 70%+ of its thermal performance — your heating bill is already paying for the failed roof.

10. Multiple repair quotes in 2 years

If you've had three or more genuine repair call-outs in 24 months for different defects, the roof is telling you it's done. Money spent chasing repairs would have paid down a strip-and-re-roof inside 5 years.

Repair (£150–£1,500)

1–5 slipped tiles, single leak in single position, isolated ridge or flashing failure. Typical lifespan extension: 5–15 years.

Partial re-roof (£1,500–£4,500)

One face of the roof failing, one valley collapsing, one chimney stripping back. Replace the affected section properly while leaving sound areas. Typical lifespan extension: 15–25 years.

Full strip-and-re-roof (£6,500–£14,000)

Full strip of tiles and felt, replacement underfelt and battens, dry-fix ridge system, re-lay or replace tiles, full new lead flashings. Typical service life: 50+ years.

Honest contractors will quote both repair and replace where genuinely viable, with realistic timeframes for each. We do — see our roof repair service for repair scope and our repair vs replace guide for the deeper decision framework.

Insurance vs replacement. Insurance covers sudden damage (storms, fallen trees), not gradual wear. A 70-year-old end-of-life roof failing in winter is wear, not damage — your insurer will decline. Replace before you need a claim, not after.

Energy performance. Full re-roofs are the natural moment to upgrade insulation and add breathable underfelt. The combined effect typically cuts winter heat loss by 25–35% on uninsulated post-war stock.

Building Regulations. Stripping more than 25% of the roof area triggers Approved Document L (insulation) and B (fire spread) compliance. Reputable contractors include the BR notification and sign-off in the quote — uninsured DIY work invalidates buildings cover and complicates future sale.

Selling soon? A failing roof shows up on every survey and either kills the sale or knocks 5–15% off the agreed price. A new roof with a transferable insurance-backed guarantee removes the issue entirely and pays back at sale.

About the Author

Jamie Pocock — Owner & Lead Contractor

Jamie has 25 years' hands-on experience in roofing and building across Hertfordshire and Essex. He runs every J&Co Contractors project personally — from quote to completion — and writes these guides from real on-the-tools knowledge of what works, what doesn't, and what costs what in 2026.

• 25 years' hands-on roofing and building experience
• CRC Certified Roofer — self-certifies under Building Regs
• SafeContractor approved
• Insurance-backed workmanship guarantee on every job