Small lead roofs on period fronts are easy to overlook and awkward to repair. Here is how they work, the faults to look for, and why the front elevation of a protected house changes what you may do.
Some Victorian and Edwardian houses in Margate, Ramsgate and Broadstairs have a bay window on the front, and some have a small porch over the door. Above each there is a short length of roof, often almost flat, and on a period house that roof may well be covered in lead. The roof is a few square metres in size and carries the whole front of the house's weather on a small area.
It also tends to be overlooked. A bay roof is out of sight from the pavement and from most rooms, and the first sign of trouble is a stain inside the room below. By then the damp has usually been working for some time. A small roof is quick to inspect and, caught early, a modest job to put right.
This guide belongs to our lead roofing work. It covers how the roof is built, what goes wrong, the lead specification and, because these roofs sit on the front elevation, the planning and consent rules that apply to a front roof.
How a lead bay or porch roof is built
A bay window projects from the wall, and the roof over it is a small timber deck, boarded and covered. Lead is laid over the boards in sheets. Because lead expands and contracts as the temperature changes, a roof is not covered in one piece. The sheets are joined at upstanding timber rolls, running down the fall, and at steps called drips across it, which let the lead move without splitting.
At the point where the bay roof butts against the main wall, a flashing is dressed up the brickwork and tucked into a joint. On a bay, the run along the top is the apron, the lead that carries water out onto the roof. At the sides, where the bay roof meets the window's returns, lead is dressed up to a cheek or turned into the wall. A porch has a similar arrangement over a smaller area.
The pieces of a bay roof:
- the timber deck, which gives the lead its support
- the lead sheets, joined at rolls and drips
- the flashing along the wall above it
- the edge detail at the front, which throws water clear of the face of the bay
- the outlet or gutter that takes the water away
MyJobQuote gives over 80 years for lead flashing, and HomeBuilding gives 60 to 100 years for a lead flat roof. Those are typical ranges and not promises, and a small roof on a front elevation takes sun, frost and driving rain full on.
Where bay and porch roofs go wrong
The faults on these roofs show up in a handful of places. The roof is low, and water has less fall to run away with than on a main slope, so a minor fault matters sooner.
- A split in the lead at a drip or a roll, where the metal has moved and cracked from fatigue.
- A lifted or pulled-out flashing at the wall, where the mortar it was tucked into has weathered away.
- Water ponding on the deck because the fall is shallow or the outlet is blocked.
- Rotten boards underneath, which let the lead sag and split in turn.
- A blocked gutter or outlet on the front edge, filled with leaves and moss.
The rotten boards are the one to look for. Lead is not the first thing to give way on a leaking bay roof. What fails first is often the timber under it, soaked by a slow leak long before a stain appears inside. Once the boards have gone soft, patching the lead on top does little, because the next sheet has nothing firm to lie on.
Moss and leaves can collect on a low roof, and since a bay roof is out of sight, cleaning it is easy to forget. A look from an upstairs window every so often is the quickest inspection there is. If the lead at the wall has lifted, our page on the lead apron explains what the flashing is meant to do.
Lead codes for a small roof
Lead sheet comes in codes that stand for thickness. The Royston Lead brochure gives the range below, and each code carries a colour mark on the roll.
| Code | Thickness | Colour mark |
|---|---|---|
| Code 3 | 1.32 mm | Green |
| Code 4 | 1.80 mm | Blue |
| Code 5 | 2.24 mm | Red |
| Code 6 | 2.65 mm | Black |
| Code 7 | 3.15 mm | White |
| Code 8 | 3.55 mm | Orange |
The brochure recommends Code 3 for soakers and for nothing else. For every other part, including the covering of a bay and the flashing at its wall, the specification fixes the code, so no single number can be named as the right one for a bay. The same brochure lists work on historic or listed buildings among the uses of lead sheet, and a bay on a period front is exactly that sort of work.
Lead sheet roofs are covered by BS 6915, which Approved Document C points to. The flat-roof standard BS 6229:2025 is for membrane roofs and does not apply to lead. That matters on a bay. The fall and the details come from the specification written for the lead roof and not from the rules for a felt or single-ply roof, and a surveyor who applies the wrong set of rules will draw the wrong detail.
For an owner, the practical question to put to a roofer is which code the quote assumes for the bay, which for the wall flashing and which for any soakers. Each of those answers should be in writing, so that the specification can be read back later.
Front elevations and conservation areas
A bay or porch is on the front of the house, and the front is the part of a protected house that councils pay most attention to. The rules depend on the council, and nothing about a bay roof makes it exempt.
In a conservation area, a change to a roof covering on the front can be controlled by an Article 4 direction. An Article 4 direction is the means by which a council withdraws particular permitted development rights from a defined area. What it covers varies from council to council:
- Swale Borough Council's Article 4 direction for Faversham extends to roof coverings, so a covering on the street side of a house there is within its reach.
- Dover District Council says a direction can reach roof alterations to a home on whichever side faces a highway, a waterway or open ground.
- Thanet District Council has Article 4 directions in the Pegwell conservation area and the Ramsgate ones, and the classes that apply at an address are a question for that council.
Thanet has 27 conservation areas, including Margate, Cliftonville, Broadstairs and Ramsgate. Canterbury has 97, Dover 57 and Swale 51. For an address in any of them, ask whether an Article 4 direction applies before the work is planned. What a direction covers in Canterbury, or in Folkestone and Hythe, is a question for that council itself to answer.
Like for like: the safe route
Like for like is repair that copies what was there: the same metal, laid the same way, in the same spot. A split lead sheet on a Victorian bay, renewed in lead of the specified code with rolls and drips as before, is like for like. Swapping the lead for another covering is a change, and on the front of a protected house it is one to raise with the council first.
Thanet District Council's conservation area page puts it as a likelihood: work that matches the existing is less likely to require planning permission. That is Thanet's wording for Thanet's addresses and is not a rule for other councils.
For a listed house, section 7 of the Planning (Listed Buildings and Conservation Areas) Act 1990 requires listed building consent for works that would affect the building's character. A repair that matches the original keeps the character, though whether the work needs consent is for the council to say. Our page on leadwork on listed buildings goes through the consent route.
Three further points:
- Replacing a roof covering can raise a Building Regulations question. The Planning Portal's test asks whether less than 25 per cent of the building envelope and less than 50 per cent of the roof is affected.
- For Dover addresses only, the district's building control list includes replacing a roof covering, including a straight like-for-like swap.
- A new porch at ground level whose floor area does not exceed 30 m² is exempt under Schedule 2 of the Building Regulations 2010.
What happens at the survey and the repair
A small roof on the front of a house is surveyed in person, because most of what matters is invisible from the ground. The surveyor goes up, usually from a ladder or a tower at the front, and works through the following.
- Looking at the lead for splits, lifted edges and ponding.
- Testing the boards beneath for softness, from the edges and from inside if there is access.
- Checking the flashing at the wall and the mortar it is tucked into.
- Looking at the outlet or gutter at the front edge.
- Finding out whether the address is listed, or lies in a conservation area or an Article 4 area.
Photos of the roof itself come back to you, so what was found is plain to see. The repair then follows what was found. A single split can be repaired, a flashing re-dressed, and a blocked outlet cleared. Where the boards are soft, the lead comes up, the deck is renewed, and new lead is laid to a specification you can read.
If a ladder or tower stands on the pavement, the access is discussed beforehand. Should a scaffold be needed over the pavement, Kent County Council is the licensing body and the scaffolding firm applies, giving 5 working days' notice, with a fee of £52 per week for 2026 to 2027. Pricing comes after the survey, as a single written total.
