How Do You Know If Your Roof Needs Repairing?

Roofs fail gradually, not suddenly. By the time water is visibly coming through a ceiling, the damage has usually been building for months. Catching the early signs saves money and avoids the kind of emergency callout nobody wants.

Which roof problems are emergencies?

Not every warning sign needs the same response. Use this as a rough guide to how quickly to act:

Severity	Examples	Suggested action
Immediate danger	Sagging ceiling, falling tiles, a large storm-created opening, water near electrics	Keep the area clear and call urgently
Prompt inspection	Missing tiles, damaged flashing, a recurring damp patch, visible daylight in the loft	Arrange an inspection within a few days
Monitor and maintain	Light moss, ageing gutters, isolated surface wear	Photograph it and schedule a routine assessment

General guidance, not a substitute for a site-specific assessment. If in doubt, treat it as the more urgent category.

How often should a roof actually be checked?

A yearly visual check, plus an extra look after any severe storm, is sensible maintenance for most roofs — the right frequency depends on the roof's age, material, exposure and past condition. The NFRC's homeowner's guide to roof work is a useful independent reference if you want to understand what a professional check normally covers.

Most homeowners never do this — the roof is out of sight, so it stays out of mind until there's a leak. For older properties common across West Sussex — Horsham stone roofs, Sussex clay tile, and slate on Victorian and Georgian buildings — that matters more, not less. As Horsham District Council's own re-roofing guidance notes, it's often the fixings that fail first on older roofs — corroded nails on old slate, for example — well before the slate or tile itself gives out.

What are the visible warning signs from ground level?

Start with what you can see without a ladder — most of these are visible from the garden, the street, or an upstairs window:

Sign	What it usually means	Urgency
Slipped, cracked, or missing tiles	Fixings failing, wind uplift damage	Book within 2–4 weeks
Sagging roofline or dip in the ridge	Structural timber weakening, potential rot	Urgent — book this week
Moss or heavy algae growth	Trapped moisture, degrading tile surface	Monitor, book within 1–2 months
Rusted or damaged flashing around chimneys	Water ingress point at the weakest junction	Book within 2–4 weeks
Gutters overflowing or pulling away from fascia	Blockage or fixing failure, water running down the wall	Book within 2–4 weeks
Granules collecting in gutters (felt/asphalt)	Surface breaking down, nearing end of life	Get an assessment

What are the signs inside the property?

Internal signs usually mean water has already found a way in:

Damp patches or discolouration on ceilings, especially after heavy rain — this is often the first sign anyone notices, and by this point water has typically been tracking through the roof structure for some time.
Daylight visible through the loft roof — check on a bright day with the loft lights off. Any daylight means there's a corresponding way in for rain.
Musty smell in the loft or top-floor rooms — a strong early indicator of trapped moisture, even before visible staining appears.
Sagging or bowing ceiling in a top-floor room — this points to water sitting in insulation or timber above, and should be treated as urgent.

AJW Roofing carrying out a residential roofing repair in West Sussex — Anthony and the team on site in West Sussex. Photo caption to be updated with the specific job/defect once a matching image is available — see dev note.

Can condensation look like a roof leak?

Yes — and it's easy to mix the two up. Condensation in a poorly ventilated loft can wet timbers, insulation and underlay even when the roof covering outside is intact. A genuine leak often gets worse after rain and tends to follow the same route each time, whereas condensation usually appears more widely during cold weather rather than after a specific downpour. Because the symptoms overlap, it's worth having the roof covering, ventilation and loft conditions checked together rather than assuming either cause on its own.

Which parts of a roof most commonly let water in?

Water rarely gets in through the flat, open expanse of tiles or slates themselves — it's the junctions and details that usually fail first:

Chimney flashing and soakers — the join between chimney and roof is one of the most common failure points.
Valleys — where two roof slopes meet and water is channelled in higher volume.
Ridge and hip junctions — mortar or dry-fix systems here can loosen over time.
Rooflights and vents — any penetration through the roof covering is a potential weak point.
Gutters, fascias and outlets — blockages here send water where it shouldn't go, even if the roof covering itself is sound.
Flat-roof seams and upstands — laps, outlets and standing water are the usual culprits on flat sections.

How does the age of a roof affect whether it needs repairing?

Age matters, but condition matters more than a simple percentage of a roof's theoretical lifespan. Roof-covering lifespan varies widely — natural slate can remain serviceable for many decades, but corroded fixings may fail earlier; concrete and clay tiles also vary by product, exposure and installation quality; felt systems tend to have shorter service lives than slate or tile, though workmanship and detailing matter as much as the material's age.

An isolated defect on an otherwise sound roof is usually repairable, whatever the roof's age. Replacement becomes more likely when failures are widespread, the underlay or battens have deteriorated, structural timbers are affected, or the same area keeps needing attention every year or two. If you don't know your roof's age, a professional inspection will usually date it fairly accurately from the materials and fixing methods used.

What does a professional roof inspection check?

A proper inspection looks well beyond the one tile or patch that prompted the call. Depending on access and roof type, it typically covers:

Slipped, cracked or missing tiles and slate, and the fixings holding them
Ridge, hip and verge details
Chimney flashing, soakers and back gutters
Valleys and other roof junctions
Flat-roof seams, outlets and any standing water
Gutters, fascias and soffits
Visible underlay, battens and roof timbers from the loft side
Loft moisture and ventilation, and any previous repairs or recurring weak points

The aim is to find the entry point, understand the underlying cause, and tell you whether it's an isolated defect or part of wider wear — not just patch the symptom you called about.

Can home insurance refuse a roof-damage claim?

Insurance risk It depends on the cause. Buildings insurance typically covers sudden, unexpected damage — a storm, a fallen branch. It generally doesn't cover gradual deterioration from lack of maintenance, and insurers can decline a claim if the roof was already showing wear before the incident. Cover, exclusions and evidence requirements vary by insurer and policy, so it's worth checking your own documents rather than assuming a repair — or any resulting internal damage — will automatically be covered. Getting problems fixed as they appear isn't only cheaper; it also protects your position if something bigger happens later.

Anthony's note — West Sussex homes On older properties around Pulborough and Horsham, north-facing roof slopes tend to stay damp longest after rain, since they get the least direct sun to dry out. If you're checking your own roof for moss or algae, that's usually the side worth looking at first.

What should you do when you notice signs of roof damage?

Don't get on the roof yourself. Most of these signs are visible from the ground, from an upstairs window, or from inside the loft. If in doubt, a professional inspection is quick and tells you exactly what you're dealing with — an isolated repair, or something more.

AJW Roofing has been trading in West Sussex for over 15 years, is family-run, fully insured, and is rated 9.8/10 on Checkatrade from 105 verified reviews. We're a local roofing contractor based in Pulborough, and if you're searching for a roof repair near me in Pulborough, Horsham, Billingshurst, Storrington or the surrounding West Sussex villages, we can usually inspect and quote within a few days. We cover residential pitched roof repairs and chimney repairs across the area.

Spotted any of these signs? Get a free quote, or get in touch directly — Anthony or Emma will tell you straight whether it's a quick repair or something bigger:

FAQs

How quickly should a slipped tile be fixed?+

Within a few weeks ideally — a single slipped tile is a minor job, but it's also an active entry point for water every time it rains. It rarely stays a one-tile problem for long.

How do I know if a leak is coming from the roof, or from something else?+

Water often travels along roof timbers before dripping through, so the stain on your ceiling is rarely directly below the actual entry point — it can be well over a metre away. A professional inspection that checks the roof covering, flashing, and guttering together is the only reliable way to trace it back to the source.

Does moss on the roof actually cause damage, or is it just cosmetic?+

Light moss isn't automatically evidence that the roof has failed. Heavy growth can retain moisture, obstruct drainage and conceal cracked or displaced coverings underneath, so it's worth having it assessed and professionally removed rather than left to spread — pressure washing or harsh scraping can itself damage some tiles and surface finishes.

How do I know if it's a repair or a full replacement?+

An isolated defect on an otherwise sound roof is usually repairable, regardless of the roof's age. Replacement tends to make more sense when failures are widespread, the underlay or battens have deteriorated, structural timbers are affected, or you're calling a roofer out for the same section more than once a year. Condition matters more than age alone — a professional inspection can tell you which situation you're in.

How do I know if a leak is coming from the roof, or from something else, if I've already had it checked once?+

If a repair hasn't resolved a recurring leak, the original diagnosis may have addressed a symptom rather than the actual entry point — this happens most often with chimney flashing and valleys, where water can travel some distance before it becomes visible. A second inspection that traces the full route, not just the area directly above the stain, is usually the next step.

What happens if I ignore early warning signs of roof damage?+

Roofs fail gradually — moisture gets into the timber structure long before there's a visible leak, and that's far more expensive to fix than the original tile or flashing issue. Left long enough, this can mean replacing roof timbers, insulation, and ceilings, not just the roof covering itself.

Should I check my roof after a storm, even if nothing looks obviously wrong?+

It's good practice. Wind can loosen tiles and fixings without an obvious sign until the next heavy rain finds the gap, so a quick visual check — or a professional one if you're unsure — after any severe storm is sensible, even when nothing looks wrong from the ground.

Can I repair a roof myself?+

Be cautious. HSE guidance treats all roof work as high-risk, even tasks that take only a few minutes, and stresses the need for safe access, suitable equipment and competent people. Most homeowners don't have the right access equipment or experience to assess fixings safely, so a professional inspection is the safer route even for something that looks minor.

About the author: Anthony has run AJW Roofing for over 15 years alongside Emma, covering residential and commercial roofing across Pulborough, Horsham and West Sussex. AJW Roofing is family-run, fully insured, and rated 9.8/10 on Checkatrade from 105 verified reviews.