The short answer
A parapet gutter is reached from a roof access, a hatch or a scaffold platform, with boards laid so nobody stands directly on the lead. Debris is lifted out by hand, the outlets are cleared and the lead is inspected for splits, ponding, open joints and loose flashings. A water test confirms that it drains. Findings are photographed so you can see the gutter for yourself.
Getting to a gutter nobody can see
Behind a parapet, the gutter lies at the bottom of the slope, with the upstanding wall on its outer side. It is common on town houses, terraces and public buildings where the front is finished with a stone coping and the rainwater is hidden. Its great virtue is its tidy appearance, and its drawback is that nobody looks at it until water comes through a ceiling.
Reaching it is the first job. Some have a hatch or a door from the loft or stair that opens onto the roof. Others are reached by a roof ladder from a lower roof, or from a scaffold or a mobile access platform erected for the purpose. We choose the route to suit the building, and that choice is a safety decision before it is a cleaning one: the work is at height, beside an edge, on a surface that can be slippery.
On a tall or exposed building, edge protection or a platform is the sensible answer. A ladder alone is seldom enough for more than a quick look. The access plan is agreed at the survey, so that nobody improvises on the day.
Protecting the lead while working
Lead is soft. Boot heels, ladder feet and tools dent it, and a deep crease can turn into a crack over the years. For that reason people do not walk directly on the lead bed if it can be avoided. Boards or crawl boards spread the load and keep boots off the metal, and tools with sharp edges are kept out of the gutter.
Clearing is done by hand, with a small scoop or trowel of a soft material, and a brush. Wet moss, silt and leaf mould are lifted out and bagged, not pushed towards the outlet where they would form a plug. Wire tools and metal scrapers are avoided, since they score the surface and open a path for corrosion.
Debris from an old lead gutter should be bagged and disposed of properly rather than left on the roof or tipped in the garden. Our page on lead and health explains why a tidy approach matters.
Birds sometimes nest in a gutter, and bats can roost in roof voids nearby. Both are protected by law, so a nest or a roost halts the job until proper advice is in hand.
What the inspection looks for
With the gutter clear, the lead can be read. We follow its length from one end to the other, looking at each of these in turn.
- Falls and ponding. The bed is laid with a slight slope towards the outlet. British Standard guidance for flat roofs recommends a minimum fall of 1 in 80 in the finished surface, designed at 1 in 40 to allow for tolerances. Standing water in the bed shows that the fall has gone or the boards beneath have sagged.
- Drips and laps. The steps along the gutter and the overlaps between sheets are where cracks usually start. Our page on the drip in a lead gutter explains what they are for.
- Splits and pinholes. Hairline splits are easy to miss until the lead is dry and clean.
- Upstands and flashings. The lead turned up the parapet and the roof slope needs to be tight and well tucked in.
- Outlets. The hopper or outlet, and the downpipe beyond it, take the whole gutter's flow. A part-blocked outlet leaves the water with no way out.
Testing and recording
A visual check does not show everything, so a gutter is often water tested. Clean water from a hose is run into the highest end, and we watch how it travels, whether it ponds, and whether it leaves by the outlet as it should. If a ceiling inside has been marked by a leak, someone watches from the loft or room below while the test is made.
We photograph what we find, before and after clearing: the state of the lead, the outlet, any splits and any damage to the stonework behind. Pictures matter in a hidden place, because you can then see exactly what the roofer saw. They also help if a repair is needed, or if the building is listed and the council needs evidence, a subject we cover in our answer about a lead alternative on a listed building.
If a fault is found, the options are explained up front: a local repair, a welded or patched section, or relining the length. A reline is a larger job, and typical UK costs of lead work are discussed in our guide to leadwork costs. A fixed price follows the survey.
How often, and what you can do yourself
There is no number of years that fits every roof. The right interval depends on the trees nearby, the pitch of the slope feeding the gutter and the number of outlets. As a working rule, a hidden gutter is worth looking at once a year, after the leaves have fallen, and after any severe storm. It is the sort of place where one blocked outlet can undo years of sound lead.
You can help from inside. After heavy rain, check the ceilings and walls below the parapet for new marks, and check the loft for darkened timber along the eaves. Do not climb out to look yourself unless there is a proper, guarded access, since a parapet gutter edge is exactly the sort of place a fall happens.
If you would like a gutter checked, our lead roofing team covers Bath and the towns within 30 road miles, and it helps to tell us where the outlet sits and whether water has shown inside, so the first visit can go straight to the likeliest fault.
