Roof repairs
across Lancashire.

Roof repairs explained

What actually
goes wrong.

Most roofs don’t fail all at once. They fail at the weak points: a slate whose nail has rusted through, a ridge whose mortar has cracked, a strip of lead that’s lifted in the wind. Here’s what we see most on Lancashire roofs, what causes it, and how a proper repair deals with it.

Slate roof repairs

Natural slate covers a huge number of Lancashire’s terraces and older houses, especially in the mill towns of East Lancashire. Slate itself can last well over a century. What usually gives up first is the nail holding it. Older roofs were fixed with iron nails that slowly rust, and when they fail the slate slides down the roof. Roofers call this nail sickness, and one slipped slate is often the first sign that others will follow.

A handful of slipped slates can be refixed with a tingle: a small strip of lead, copper or stainless steel nailed to the batten under the gap and folded up over the bottom of the slate. It’s a quick, tidy fix. If slates are slipping all over the roof, though, refixing them one by one stops making sense, and the honest answer is a re-slate that reuses the sound slates.

Matching matters on slate. A new slate that’s the wrong size, thickness or colour stands out from the street, so we look for reclaimed slate first and only use new where it blends in.

Tile roof repairs

Most post-war estates are roofed in concrete interlocking tiles, while older and more traditional houses often have clay plain tiles. Tiles crack from frost, from being walked on, or from something heavy landing on them, and some older profiles are no longer made, which makes reclaimed tiles the only good match.

Replacing a tile means lifting the ones around it, sliding the new one in and fixing it properly. Since the 2014 revision of BS 5534, the British Standard code of practice for slating and tiling, all single-lap tiles are expected to be mechanically fixed with nails or clips rather than just hooked over the batten. When we replace tiles, we fix them to that standard.

Ridge and hip tiles

Ridge and hip tiles cap the top and corners of the roof, and traditionally they were held on with nothing but sand and cement mortar. Mortar cracks as the roof heats and cools, the joints open up, and eventually tiles work loose. A loose ridge tile in a storm is a genuine hazard.

BS 5534 now says mortar alone isn’t enough: ridge and hip tiles should be mechanically fixed, even when they’re bedded in mortar. That leaves two good options. We can re-bed the ridge in fresh mortar and fix each tile with clips and screws, or fit a dry-fix ridge system that holds the tiles mechanically with no mortar at all, needs very little maintenance and often adds roof ventilation. On older or listed buildings, where the look of a mortar ridge matters, we’ll talk through which suits.

Valleys, flashings and leadwork

If we had to bet on where a leak is coming from, we’d bet on the joins. Most leaks start where the roof meets something else: a chimney, a wall, a dormer, or another roof slope in a valley. These joints are sealed with lead flashing, tucked into the mortar joints of the brickwork and dressed over the slates or tiles.

Lead is long-lasting when it’s the right thickness and fitted properly, but it splits if pieces are too long, lifts in high winds if it isn’t secured, and comes away when the pointing holding it fails. Cheap fixes like a bead of sealant or a mortar fillet in place of lead rarely last. We replace failed flashings with new lead, cut and dressed on site to suit the roof.

Finding a leak

The stain on your ceiling is rarely directly under the problem. Water gets in, runs along the underlay or down a rafter, and drips wherever it finds a way out. That’s why a leak needs tracing, not guessing. We start in the loft, looking for wet timber, staining on the underside of the felt and daylight where there shouldn’t be any, then work out on the roof from there.

Finding the real cause is the difference between a repair that lasts and a call-back after the next downpour.

Flat roof repairs

Flat roofs on extensions, garages and dormers come in three main types. Felt (built-up bitumen) roofs crack, blister and lose their surface over time. EPDM rubber roofs are tough but can lift at the edges or split where they’ve been cut around pipes and outlets. GRP fibreglass roofs can crack at joints and corners where the deck moves.

Small splits and blisters can usually be patched. Water sitting on the roof after rain, called ponding, is worth taking seriously, because it means the roof isn’t draining and every repair will be under constant attack. If a flat roof is patched in several places and still leaking, it’s usually time to re-cover it rather than keep patching.

Temporary vs permanent repairs

When water is coming through the ceiling, the first job is to stop it. A temporary repair, sometimes called a make-safe, might be a sheet over the damaged area, a slipped slate pushed back into place or a patch on a split flat roof. It buys time.

A temporary fix isn’t a repair, though. Once the weather allows, the cause needs fixing properly, with the right materials and fixings. If anyone offers to “sort it with a bit of sealant” and leave it there, that’s a bodge, whatever their name is.

Lancashire weather and your roof

Where you live in Lancashire changes how your roof wears. On the Fylde coast, in Blackpool, Fleetwood and Lytham St Annes, wind-driven rain and salt off the Irish Sea are hard on ridges, flashings and flat roofs. In the Pennine-edge towns like Burnley, Accrington and Blackburn, damp and shade mean moss, blocked gutters and frost-damaged slate. Around Lancaster and the Ribble Valley, stone houses, heavy slate roofs and conservation areas mean repairs need to match what’s already there.

That local wear is why our town pages go into more detail about the roofs we see in each area.

Can I fix it myself?

Falls from height are one of the biggest causes of serious injuries at work, and a roof is no safer at the weekend. We’d always say leave anything on the roof itself to someone with the right access equipment. There are still useful things you can do safely from the ground:

• Check the roof from the street or garden with binoculars after a storm.
• Look in the loft for damp, stains or daylight, and take photos.
• Keep gutters clear if you can reach them safely from a stable ladder.
• Note when a leak appears, for example only in heavy rain or only in wind from one direction, as it helps trace the cause.