Owner
9 min read
Flashing is the thin waterproof layer at roof junctions, chimneys and abutments are the usual failure points in Stirling wind driven rain.
Avoid mastic bodges, the right fix is usually proper leadwork (Code 4 or Code 5) chased into masonry with correct laps and fixings.
Budget from £450 to £900 for a small flashing repair without scaffold, and £1,500 to £3,500 for a typical two storey chimney flashing renewal with scaffold in Stirling and Alloa.
If you have a leak that keeps showing up at the chimney breast, a gable wall, or the top corner of a dormer, it is usually flashing. Flashing is what seals the awkward joins, it takes the brunt of Stirling weather, especially when we get wind driven rain like we saw in Babet and the back to back storms in January 2024. The good news is most flashing faults are fixable without touching the whole roof, but the repair needs done properly, not silicone smeared over cracks. Below I will show you what flashing is, the common failure patterns we see around Stirling, Alloa and Falkirk, and what you should expect to pay in 2026.
Roof flashing is a thin waterproofing material fitted anywhere the roof covering meets something else. Think chimneys, dormer cheeks, roof to wall abutments, valleys, hips, verges, parapets, rooflights, and around soil vent pipes. On a lot of older Stirling stock, you will see lead dressed into place with step flashing at the sides of the chimney and an apron to the front, sometimes with a back gutter (back tray) behind. On slate roofs, you can also have lead soakers under the slates at abutments.
Flashing fails because it moves and it is exposed. Lead expands and contracts, mortar cracks, fixings loosen, and once water gets a track behind it, it will show inside the house. In Central Scotland we get spells of heavy rain with strong gusts, that is when weak junctions show up. Standards like BS 5534 (slating and tiling) and BS EN 12326-1 (roofing slate quality) are useful benchmarks, but on a real roof in Bridge of Allan or Fallin, good detailing and access are what decide if it stays watertight.
The most common issue we get called to in Stirling and Alloa is not a broken slate, it is a junction that has been patched a few times and is now letting water in again. Typical faults are: split lead at a bend line, step flashing that has lifted out of the chase, short laps where two pieces meet, and cement pointing that has failed so water runs behind the lead. Another big one is someone has tried to “seal” flashing with mastic, it works for a winter then opens up.
Do not ignore gutters either. An overflowing gutter can make it look like flashing has failed because the water is backing up at the eaves and tracking in. If you are seeing damp at the top of a wall, check the gutter line, fascia, and soffit condition. We often end up doing a small tidy on the rainwater goods at the same time as a leak repair, see fascias, soffits and guttering for what that usually involves.
If you are unsure whether you need a minor fix or something bigger, start with a proper inspection as part of a roof repair. We will check the flashing, the underlay or breathable membrane, the sarking condition where visible, slate gauge and fixings, and any signs of water tracking on timbers. That saves you paying for the wrong repair.
Common after strong gusts, the lead can lift at an abutment or the edge can crease and crack. You usually see it after storms when the rain is driven up the roof.
On chimney step flashing, the chase in the masonry needs sound pointing. If the mortar is crumbling, water gets behind the lead and runs down the inside face of the stack.
If the overlaps are too short or joints are in the wrong place, water can track in by capillary action. This is common on rushed repairs where lead was cut small to save material.
Silicone and bitumen patches split quickly in our climate. They also trap water and make the proper repair harder later.
Chimneys are the number one flashing leak point across Stirling, Falkirk and the villages. The water has a lot of ways in: step flashing at the sides, an apron at the front, and a back tray (back gutter) that takes the run off behind the stack. If the back tray is split or not dressed properly, it can dump water straight into the roof space. You often only notice it when the plaster on the chimney breast stains or bubbles.
Access is the catch. A two storey chimney on a 1930s house in Bannockburn, or a taller property near Stirling town centre, usually needs scaffold to do the job safely and to the right standard. It is also common that the leadwork is not the only issue. We regularly find loose brickwork, perished flaunching on top, or failed pointing that needs done alongside the flashing. That is why we price chimney repairs as a package rather than pretending it is just a bit of lead.
– William Young, Owner
For most traditional roofs in Stirling, lead is still the right answer. It shapes well around awkward details, it lasts if it is detailed properly, and it is repairable by a competent leadworker. We mostly use Code 4 for soakers and lighter details, and Code 5 where you need a bit more strength, such as chimney aprons and trays. If your roof is slate, especially Welsh slate or reclaimed Scotch slate, lead soakers and step flashing are the tried and tested approach, see slate roofing for the way we typically build those junctions.
Aluminium can be a cost effective option on some modern details, but it is not a magic fix. It still needs correct laps, correct fixings, and proper chasing into masonry where required. The other thing is planning and appearance. In parts of Stirling with conservation sensitivities, swapping visible lead for a different metal can cause issues. If your property is listed, like for like repairs are often the sensible route, and that usually means lead. If you want a deeper run through on leadwork details, see Article 11 on leadwork.
First step is diagnosis. A flashing leak can look like a cracked tile, a ridge issue, or water coming over the gutter in heavy rain. We look for water tracking marks on timbers, staining on sarking where visible, and damp lines in the underlay or breathable membrane. We also check nearby details like valleys, verges, and the condition of the batten ends at the eaves. If the roof is slate, we check for slipped slates and nail sickness, because a nail failure beside an abutment will mimic a flashing problem.
The fix depends on what is actually wrong. If the lead is sound but loose, we can often refix and re dress it, and renew the chase pointing. If the lead is split, short lapped, or patched repeatedly, we cut it out and replace it with correctly sized pieces and proper laps. On chimney work, that normally means new stepped flashing, new apron, and a back tray if needed. If the repair ties into wider roof work, we will also discuss the overall roof condition and whether you are better with a larger repair or a proper roofing job on that slope.
Call a roofer if the leak is active, if the ceiling is bulging, if water is near electrics, or if you can see lead lifted after a storm. We get a spike in call outs around Stirling and Falkirk after named events because wind driven rain finds the weak point fast. The other trigger is repeat leaks. If you have had the same corner patched twice, it is time to stop patching and renew the flashing properly, otherwise you will end up with rot in the battens or damaged sarking.
DIY wise, the main issue is access and detail. Chimney step flashing repairs usually need chasing into masonry, dressing lead properly, and making sure laps and cover lengths are right. That is not a ladder job for most homeowners, and it is not worth a fall. If you are a landlord in Clackmannanshire, remember a persistent leak is not just a nuisance, it can become a Repairing Standard problem quickly if the property is not wind and watertight. If you want a practical overview of what we check on a leak visit, read Article 3, roof repair guide.
Costs come down to access, height, and how much leadwork needs replaced. As a rough UK guide, full lead flashing replacement is often priced around £100 to £300 per linear metre, and small repairs can start from about £388 for a basic job. In Stirling, the big swing factor is scaffold. If we can do it safely from ladders on a single storey extension roof, costs stay sensible. If it is a two storey chimney with awkward access in a tight street, scaffold can be the difference between a £700 job and a £2,500 job.
For 2026, these are realistic ranges we see locally, including labour and materials, and usually excluding any major slate or tile replacement outside the flashing zone. Small refix or patch repair to an abutment, no scaffold, £450 to £900. Renew a short run of stepped lead flashing to a chimney side where access is good, £900 to £1,600. Full chimney flashing renewal, stepped flashing plus apron and back tray, two storey scaffold, £1,500 to £3,500. If the chimney also needs repointing or flaunching repairs, add £400 to £1,200 depending on condition, see chimney repairs for the typical scope. For a wider view of repair pricing across roof types, Article 10, roof repair costs, is a useful read.
Flashing faults are one of the most common causes of leaks we deal with in Stirling, Alloa and Falkirk, and they are usually straightforward to solve if you catch them early. The key is to repair the junction properly with the right material, the right laps, and the right fixing and pointing, not to keep chasing it with sealant. If your roof is slate or tile and the rest is sound, a flashing renewal can buy you years of dry roof without a full re roof.
If you suspect flashing is the issue, get it checked before the next spell of heavy rain. A small leak left for a season can rot battens at the eaves, stain ceilings, and turn into a bigger strip out. If you want us to look at it, we cover FK7 Stirling and out to Alloa, Clackmannanshire and Falkirk, and we will tell you straight what needs done and what can wait.
Standard roof repair and maintenance work is usually 20% VAT. If you are combining flashing work with qualifying insulation upgrades, ask about the VAT treatment before the quote is finalised.
If you have active dripping, a wet chimney breast, staining that keeps coming back after every downpour, or you have seen lead lifted after high winds, treat it as urgent. We can often make it safe with temporary weatherproofing, then come back with scaffold if the permanent repair needs it.
If it is a repeat leak at the same junction, that is a sign the flashing is the root cause, not the slates. We will inspect, show you photos of what has failed, and price the sensible fix, whether that is a small repair or new Stirling, Alloa, Falkirk, Dunblane and the wider Central Scotland area. Call 01259 726404 or message us on WhatsApp.
Repair suits localised damage where the battens, underlay, and timbers are sound. If you have recurring leaks, widespread slippage, nail sickness on slate, or a sagging ridge line, replacement is usually the sensible route in Stirling because you cannot bring it back to BS 5534 expectations without stripping.
A small refix might be possible if you have safe access, but most chimney step flashing work needs chasing into masonry and proper laps, and that is not a safe ladder job. If the roof is two storeys, scaffold is usually the right call.
A common guide price is £100 to £300 per linear metre for lead flashing replacement, with small jobs sometimes starting around £388 plus access. In Stirling, scaffold for a chimney is often the biggest extra cost.
If water is actively coming in, affecting electrics, or the ceiling is bulging, treat it as an urgent repair. After storms, wind can lift lead and drive rain in fast, so it is worth getting it made watertight the same day where possible.
William has spent over two decades on Scottish roofs, working from apprentice slater to running a Stirling-based team that re-roofs villas and repairs storm damage across the central belt. He writes about roofing the way he talks on a survey: straight, costed and honest.
40+ yrs combined experience · Stirling · NFRC member
Chimney flashing, stepped flashing, back trays and soakers in Code 4 and Code 5 lead.
Targeted fixes for slipped slates, broken tiles, valleys, and leak tracing across Stirling and the Central Belt.
Repairs and renewals on Welsh, Spanish and reclaimed Scottish slate with correct detailing.