A pitched roof fails politely. One slipped slate. A hairline crack in a tile you’d never spot from the street. A crumb of mortar in the gutter.
None of it demands attention, and that’s the trap. By the time a tiled or slate roof leaks visibly into the house, the water has usually been getting in quietly for months — soaking battens, rusting nails and staining the felt, all out of sight.
The good news: pitched roofs telegraph their problems earlier and more visibly than flat roofs, if you know what to look for. This guide covers the warning signs for tiled and slate roofs, what causes each problem, and what an honest repair involves — written from what we see on roofs across Deal, Dover and Sandwich every week.
First, Know What’s on Your Roof
It sounds basic, but the repair conversation starts here, because tiles and slates fail differently.
Clay and concrete tiles are moulded units that hook over battens, each overlapping its neighbours. Most homes built from the Victorian era onwards have them. Clay lasts longer and keeps its colour; concrete is cheaper and heavier.
Natural slate is stone, split into thin sheets and fixed with nails. It’s common on period properties around Deal’s conservation streets and across East Kent’s older housing stock. Good slate is extraordinarily durable — the slate itself often outlasts everything holding it up.
That last point matters more than any other fact in this article. On old slate roofs, the usual failure isn’t the slate. It’s the nails.
The Six Problems We Find Most on Pitched Roofs
1. Slipped and Missing Slates — Usually “Nail Sickness”
When slates start sliding out of position one by one, the cause is almost always the fixings, not the stone. The Victorian iron nails corrode, the nail holes wear, and gravity does the rest. The trade calls it nail sickness, and Historic England’s guidance on older roofs makes the key point homeowners need: corroded nails don’t mean the roof is finished. Individual slipped slates can be re-fixed with discreet metal clips called tingles, and the original slates re-used.
The judgement call is volume. One or two slips a year is maintenance. A scatter of slips across the whole roof means the fixings are failing wholesale — at that point stripping and re-laying the roof (re-using most of the original slate) beats chasing slips forever.
2. Cracked, Spalled and Delaminating Tiles
Tiles fail from weather, age and impact. Frost is the main culprit: water soaks into the tile surface, freezes, and pops flakes off — that’s spalling. You’ll see tiles with patches that look freshly broken, or layers peeling like pastry.
A cracked tile here and there is a quick swap. Widespread spalling across a roof face tells you the tiles have reached the end of their frost resistance, and each winter will now harvest a few more.
3. Ridge and Verge Mortar Failure
The tiles along the very top of the roof, and the edges at the gables, were traditionally bedded in mortar. Decades of frost and wind crack it, and on coastal roofs this happens faster — salt air and the Channel’s wind-driven rain work mortar joints hard. Loose ridge tiles are the classic find after a winter storm, and they’re heavy enough to be dangerous when they let go.
The modern fix is often a dry ridge system — ridge tiles mechanically clipped rather than mortared, with nothing to crack and re-point every decade. On period properties we’d usually re-bed in mortar to keep the original look.
4. Failed Flashings
Where the roof meets a chimney, wall or valley, sheet lead bridges the junction. These junctions are the most vulnerable part of any pitched roof — more leaks start at a chimney than anywhere else on a tiled roof. Lead lifts in wind, slips when its fixings fail, and eventually fatigues and splits.
Good leadwork outlasts almost everything else on the roof; cheap repairs with mastic and flashing tape last a winter or two. If you can see lead that’s rippled, lifted or patched with something black and shiny, that junction is on borrowed time.
5. Rotten Battens and Torn Felt — the Hidden Layer
Under the tiles sits a layer of felt (or breathable membrane on newer roofs) and the timber battens everything hangs on. You can’t see this layer from the street, but it’s where small leaks do their real damage. Tell-tale signs from the loft: daylight visible where it shouldn’t be, felt that’s torn or crumbling at the eaves, and battens that look dark and damp.
Eaves felt failure is its own common repair — the bottom edge of the felt, which carries any wind-blown water into the gutter, rots first because it stays wettest longest.
6. Moss — Mostly Cosmetic, Sometimes Not
Moss on a pitched roof alarms homeowners more than it should. On sound tiles it’s largely cosmetic. It earns attention when it’s thick enough to hold permanent moisture against the tiles (speeding up frost damage), when it sheds into and blocks the gutters, or when it lifts tile edges. Removal should be gentle — pressure washing strips the surface off tiles and forces water under them, and we’d never recommend it.
A wider tour of how roof coverings fail, with the building-science behind each defect, is on Designing Buildings’ roofing defects page if you want to go deeper.
What You Can Check Yourself — From the Ground
No ladders needed. Twice a year, and after any named storm:
- Walk the property with binoculars (or a phone camera zoomed in) and scan each roof face for slipped, cracked or missing tiles and slates
- Look along the ridge line — it should be straight and complete, with no gaps or proud edges
- Check the gutters for mortar crumbs, tile flakes and grit; the roof sheds evidence into them
- From the loft on a bright day: any daylight, any damp smell, any staining on the felt or timbers
- After a storm, check the garden and look again — our guide on storm damage roof repairs covers the full post-storm routine
What we’d ask you not to do is walk on the roof. Tiles crack underfoot, slates are slick with algae, and most of the broken tiles we replace at the bottom of a repair were cracked by someone’s foot, not the weather.
What Do Pitched Roof Repairs Cost?
Every roof is different, but homeowners deserve a rough shape before the quotes arrive.
At the small end: re-fixing a slipped slate or swapping a handful of cracked tiles is typically a same-day visit measured in the low hundreds of pounds, access permitting. Re-bedding a ridge or re-pointing a verge sits in the middle — more labour, sometimes a tower or scaffold. Chimney flashing renewals vary most, because chimneys vary most; the lead itself is rarely the expensive part, the access is.
Two things move any quote upward: scaffolding, where the repair can’t be reached safely from ladders, and hidden damage — the batten rot or torn felt that only shows once the first tiles come off. A fair quote will say plainly what’s included and what would count as an extra, and a fair roofer will photograph anything unexpected before charging for it.
Repair or Re-Roof? The Honest Arithmetic
Most pitched roof problems are repairs, not replacements. A slipped slate, a cracked tile, a re-bedded ridge — these are contained, affordable jobs, and our roof repair service handles them across tiled and slate roofs all year round.
Re-roofing earns its place when the failure is systemic rather than local:
- Slips and cracks appearing across the whole roof, season after season
- Nail sickness confirmed across multiple faces
- Felt and battens rotten beyond patching
- Repair call-outs adding up to a meaningful slice of a new roof every year
Even then, a good slate roof often keeps most of its value: with care, a high percentage of original slates can be re-used on the new fixings, which preserves both money and the roof’s character. On listed buildings and in conservation areas — and Deal and Sandwich have plenty of both — check with the council before changing the covering’s appearance; like-for-like repairs are normally fine, but a change of material can need consent.
Two Quick Questions We’re Always Asked
Can you replace just one tile? Yes — and a good roofer is happy to. Single-tile and single-slate repairs are routine work, not a nuisance job, and they’re exactly how long-lived roofs stay long-lived. Matching the tile is usually the only complication: older clay tiles and imperial-sized slates sometimes take a little sourcing, which is another argument for re-using originals wherever possible.
Why do tiles keep coming off the same spot? Because roofs have weather sides. The face that takes the prevailing wind — around here, usually the south-westerly — works its fixings hardest, and a spot that’s lost tiles twice will lose them again until the underlying cause is fixed: tired battens, worn nail holes, or an exposed verge that needs mechanical fixing rather than another bed of mortar. Repeat failures in one place are a diagnosis, not bad luck.
Small Repairs, Long Roofs
The whole economics of pitched roofing comes down to one habit: deal with the polite warnings.
- One slipped slate re-fixed this month costs a fraction of the batten and felt repair it causes next year
- Ridge mortar re-pointed before winter beats ridge tiles in the garden after a storm
- Check from the ground twice a year, check the loft after heavy rain, and check everything after a named storm
A well-maintained tiled or slate roof is one of the longest-lived parts of a house — slate especially can see out generations when its fixings are kept honest.
If you’ve spotted any of the signs above on a roof in Deal, Dover, Sandwich or the surrounding villages, we’ll take a proper look and tell you straight whether it’s a small repair or something more. Family-run, working on the area’s tiles and slates since 1997.
Call Weathered Roofing on 07379 187815 or request a free quote.