Plumbers & electricians in Herne Hill

The centre is where Half Moon Lane meets Norwood Road, with the station and its railway junctions above it and Brockwell Park rising to the west. Ground climbs in most directions from there, up towards Tulse Hill on one side and over the ridge to North Dulwich on the other. The low point is the middle, and that is no accident. The River Effra ran through here before it was culverted in the eighteen forties and swallowed by the sewer network. The river is gone. The valley it cut is not.

Before the railway arrived in 1862 this was large villas standing in their own grounds, and some survive. After it the terraced streets went up quickly, and they remain the bulk of what stands here: solid brick, high ceilings, back additions, and under a good many of them a cellar dug at the same time as the footings. Post war estates, tower blocks and newer infill flats fill in the rest. No two calls look alike. A converted house has original waste never meant to serve four kitchens, which is why a blocked drain in Herne Hill is as often a shared stack problem as one household’s. Boiler repair in Herne Hill runs from a combi in a top floor conversion to an untouched cylinder and loft tank, and the electrical work spans the same range, out to an EV charger where the only parking is the kerb.

Why a Herne Hill cellar takes water when nothing has leaked

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On a valley floor the water table sits close to the surface, and after a long wet spell it rises. Made ground and river deposits over the London Clay hold and move that water, and the culverted river below is a large pipe running full at the exact moment everything else is full. A Victorian cellar was cut into that ground with brick walls sitting more or less straight on the earth and a floor laid over bare soil. There is no membrane, because nobody built one. When the ground outside is wetter than the air inside, water comes through the wall. That is not a fault developing. It is the structure doing what it always has, in a year wet enough to show it.

What you see is a floor damp by morning, or a shallow sheet of water across the lowest part of the cellar that was not there the day before, usually a day or two after heavy rain rather than during it. It is clean, cold and has no smell. It rises at the joint between floor and wall as much as it runs down anything, and the wet areas are broad rather than pointing back to one spot. A leak runs whether it has rained or not, and keeps the meter turning with every tap shut. A blocked drain smells, and shows first at a gully or a slow WC. Groundwater does neither, and it has no source you can turn off.

The instinct is to seal it, and sealing alone is usually the wrong money. A waterproof render does not remove the water, it moves the argument. Pressure spread across the whole cellar concentrates on whatever is left unsealed, so it comes up through the floor, finds the next weak joint, or pushes the render off the wall. What lasts is a system that accepts the water and controls where it goes: a membrane that lets it run behind, a channel round the perimeter at floor level, and a sump at the lowest point with a pump to lift it out. The pump wants a supply shared with nothing else, a serviceable float, and realistically a second pump and a battery, because the night the water arrives is often the night the power goes. Where that discharge is allowed to go is not a free choice either, and whether a sump alone is enough depends on the house.