Roofs rarely fail because of a single dramatic event. More often, something fixed to them or hanging over them does slow harm for years, and the damage shows up on the first wet night after it finally gives way. Trees are the obvious case: a limb comes down in a gale, a branch rubs the same patch of tiles every windy day, or leaf litter sits in a valley until water backs up. Less obvious are the things people attach to a roof and then forget. An aerial strapped to a chimney in the 1970s, a dish bolted through the tiles when a new provider arrived, a cable clipped under a slate. Each leaves a hole, a stress or a stain that a roofer finds later. This guide takes the two sources in turn, describes how the damage looks from inside and outside, sets out how repairs are made on slate, clay and stone roofs, and explains what to do to prevent more. It also covers the practical points that come with a neighbour's tree and with insurance.
How a tree damages a roof
Trees harm roofs in four separate ways, and the repair depends on which one you have.
Impact. A falling branch can crack tiles, snap slates, bend a ridge or break battens and rafters underneath. The visible hole may be small, while the structural damage beneath is larger. Where the branch is heavy, the timbers should be checked from the loft before anyone looks only at the covering.
Abrasion. A branch that brushes the roof in every wind slowly wears the surface. On clay and concrete tiles it removes the face coating, and on slate it scuffs and flakes the edges. The tell-tale is a pale patch, always in the same place, on the side nearest the tree.
Debris. Leaves, twigs and seeds gather in gutters, in valleys (the lead-lined channels where two slopes meet) and behind chimneys. Once the channel is blocked, water spills over the edge or backs up under the covering. Hidden channels such as a box gutter, a leaded trough built into the roof, are especially prone, since you cannot see them from the ground.
Shade and damp. A roof under a canopy stays wet longer, so moss and algae take hold. Moss holds moisture against the surface and lifts the edges of tiles, and in winter, frost working into a wet tile can flake its face.
None of these needs a storm to start. For that reason we inspect the whole slope beneath an overhanging tree and not only the visible damage. A cracked slate that was found after a gale has often been joined by others that cracked quietly in the years before it, and a repair that treats only one leaves the next leak waiting.
Repairing branch damage on slate, clay and stone roofs
The method follows the covering, because each material is repaired in its own way.
Slate
Each slate is fixed beneath the course above it, which means a broken one cannot be nailed back on top. The usual repair slides a replacement into the gap and secures it with a tingle: a narrow copper or lead tab, nailed to the batten, with its free end folded up to hold the tail of the new slate. If the damage covers several slates, the courses around it are lifted and refixed. We try to use salvaged slate of the right size and weathering, because a new grey slate stands out on an old Welsh roof.
Clay and concrete tiles
Plain clay tiles hang from the battens by nibs and are held by clips and nails, so a damaged tile is lifted by raising its neighbours. Interlocking tiles are replaced the same way. The batten behind is checked, because a splintered batten will not hold the new tile.
Stone tiles
Stone slates are heavy and uneven. They are re-hung with care and, where the supply allows, replaced with reclaimed stone of the same character, since modern substitutes change the look of the roof.
Timber and ridge
If the branch has damaged a rafter or ridge board, the structure is repaired first, often by fixing a new timber alongside the old one, before the covering goes back. A bent or displaced ridge is rebuilt and fixed mechanically.
MyBuilder's 2026 repair guide lists minor jobs at £100 to £300 and moderate ones at £500 to £1,000 as typical UK ranges, with fixes after a storm at £500 to £1,500. Where a fallen tree needs scaffold, that is quoted as a separate line. A tarpaulin stops further damage meanwhile, and the page on roof tarpaulins describes how one should be secured. For a bigger break the first step is the make-safe visit, followed by a fixed price in writing.
Old aerials, dishes and the holes they leave
A television aerial or satellite dish looks like a minor addition, but it has to be anchored to something, and the something is your roof or your chimney.
Aerials are often strapped to a chimney stack with galvanised lashings and a bracket. Over time the bracket rusts and stains the masonry, the lashing loosens and rubs against the stone, and the weight of a large aerial, loaded with wind, can crack the pointing and push the stack out of line. Where the mounting was drilled into the brickwork or stone, the holes admit water to the masonry and the flue. If the aerial is still on the stack but no longer works, it is simply a load carried for nothing.
Dishes are different. Many are fixed to the wall, but some are bolted through the roof covering to a rafter or a bracket on the roof slope. A bolt through a tile or slate needs flashing or sealant to keep the hole watertight, and sealant eventually fails. When an old dish is taken down, the bolt holes remain, and those are where leaks start. The fix is to replace the damaged slate or tile, not to smear sealant over the hole, and to check the batten beneath.
Cables are the third source. A cable clipped under a tile or laid over the ridge can lift the covering slightly and let wind-driven rain in. Where cables enter the building through the roof, the entry point should be sealed and sheltered by a lead or purpose-made flashing.
In MyBuilder's 2026 chimney repair guide, the typical UK ranges are £250 to £1,200 to mend a flashing and £500 to £2,000 to repoint, which averages around £750. Scaffold explains much of the spread. Our survey looks at the stack and the slope together, and the price you sign follows it.
Chimney stacks and aerial loads
The chimney is where trees and aerials most often meet. Branches strike the top of a stack, and an aerial adds weight and leverage there. A stack in Bath may be built of stone and lime mortar. A taller stack on a gable exposed to wind takes the most punishment, and a leaning stack is a safety problem that should not wait.
Look for four signs. A visible lean, or a gap opening between the stack and the roof. Crumbling mortar around the aerial bracket. A rust stain running down the face of the stack. And damp patches on the chimney breast inside the house, typically on an upper floor.
Repair is stepped. Loose pointing is raked out and renewed, and on older stone stacks that means lime mortar, not cement, because a cement mix is harder than old stone and keeps in moisture that should be able to dry out. Flaunching is the mortar crown that sets the pots in place, and cracked flaunching lets water into the flue. Flashings, the lead dressed around the base where the stack meets the slope, are renewed if split or lifted. A badly leaning stack is taken down and rebuilt, and if the building is listed, consent has to be obtained through B&NES Council before that work begins.
An aerial that is still used can often be moved to a wall bracket or a new mounting. One that is no longer used is better removed, along with its bracket, the stained mortar repaired and the old fixing holes filled. We would rather you ask before anyone climbs, since the stack may be less stable than it looks.
If the leak seems to come from the chimney but the cause is unclear, our guide on telling a roof leak from condensation explains how to separate the possibilities. Damp on a chimney breast can be a flue problem, a flashing fault, or condensation on a cold masonry stack.
Prevention: pruning, clearing and fixing things properly
Most of this damage is preventable, and prevention costs less than repair.
Keep trees back. Branches should not touch the roof, and a gap of a metre or so is sensible so that growth between visits does not close it. The work belongs to a tree surgeon, not a roofer on a ladder. Before anyone cuts, ask the council whether the tree is protected, since some trees have restrictions on pruning. If the tree is a neighbour's, start with a conversation and a photograph. Most neighbours would rather agree a time than argue about branches.
Clear the channels. In autumn, after leaf fall, gutters, outlets and valleys should be cleared, and again in spring. If a tree overhangs a hidden gutter, a gutter guard is rarely enough; the channel needs checking by hand.
Treat the surface. Moss on a shaded roof can be removed gently by hand. Pressure washing can damage slate and soft tiles, so we avoid it; the roof cleaning service explains the gentler methods.
Put fixings in the right place. A dish belongs on a wall bracket where possible, not on the roof. If it has to go on the roof, it needs a bracket fixed to the structure, with the penetration flashed. An aerial no longer in use should come down.
Plan for birds and bats. Tree work and aerial removal can disturb both, and both are protected, so timing matters.
Winter is the season of most tree damage, and the winter roof repairs guide sorts out which repairs proceed in cold weather. The repair itself is covered by our roof repairs service, where a free survey comes first, the photographs show your own slopes, and a fixed price is put in writing afterwards.
Who pays: neighbours, insurers and records
Damage from a tree raises practical questions about responsibility, and a roofer cannot settle them, but we can help you gather what you need.
If your own tree caused the damage, the repair is yours to arrange, and it may be covered by your buildings insurance if the cause was a storm. If a neighbour's tree dropped a branch, the first step is a polite note with photographs. Some householders' policies respond to such damage, and the neighbour's insurer may be involved if there is a dispute. Citizens Advice publishes neutral guidance on neighbour disputes, and a solicitor can advise on liability. We do not give legal advice.
Insurers often define a storm by wind speed, and a common threshold is a gust of 55 mph. Policies commonly leave out wear and tear, so a claim for damage that built up slowly under a rubbing branch may be treated differently from a branch that fell in a gale. Photographs taken before and after help in either case. We do not handle claims for customers, and we cannot promise that one will succeed.
The records worth keeping are simple. Dated photographs of the tree and the damage, the weather on the day, a written report from a roofer describing the cause, and receipts for any emergency work. Our survey report gives you the roof side of that, with photographs and a note of what the damage was and how it was repaired.
Once the repair is finished, our written guarantee on workmanship runs for ten years. The site is cleared and waste taken away, including the broken slates and any debris the tree left behind.