Leak Detection in the City of London

A Building Stock Unlike Anywhere Else in London

The numbers set the tone. Over 500,000 people worked in the City in 2019, and the 2021 census counted 8,583 residents living there. Almost everything we are asked to survey is therefore an office, a shop, a restaurant or a mixed use building, and the person who calls is usually a facilities manager or a managing agent with a tenant on the phone and a wet ceiling tile on a photograph.

Water in a commercial building travels sideways along the slab before it drops, so the floor reporting the damage is often not the floor with the fault. Restaurants and cafes concentrate that risk. Pipework to dishwashers, glass washers, coffee machines and floor drains is packed into a small kitchen, usually behind fixed units, and a weeping connection there can run for weeks. Commercial leak detection starts from £300 and the timing can be arranged around service.

Facilities Teams Need an Answer, Not Just a Repair

In a multi let building, finding the water is only half the problem. The other half is establishing whose pipe it was, because that decides whether the landlord, the tenant or an insurer carries the cost, and whether the damage becomes a service charge item or a claim. A trace and access survey at £350 to £450 sets down the position, the method and the part of the building involved, in a form all three parties can read.

Older buildings make that harder than it should be. Heating and hot water systems in a City office may have been altered through several refits, valves capped and re-run, and the drawings on file describe an earlier version of the building. Thermal imaging at £150 to £250 and tracer gas at £200 to £350 show where the pipework actually goes, which is frequently the first accurate record anyone has had for years.

The Barbican: Electric Floors, So Rarely a Heating Leak

Two estates by the practice of Chamberlin, Powell and Bon account for most of the City's resident population. The larger, the Barbican, went up between 1965 and 1976, is listed, and contains roughly 2,000 flats, maisonettes and houses. Heat in its flats comes from electric cables set into the floor slabs, a communal background system switched on by the City Corporation for the winter half of the year, from 1 October until 30 April.

That single fact changes the diagnosis. Because no hot water circulates through those floors, a Barbican leak is rarely a heating leak in the sense meant anywhere else in London. What does appear is far more often mains or waste water, or the contents of an appliance, or a bathroom in the flat above. Residents are asked to take water penetration to the Barbican Estate Office Repairs Service Desk, which normally opens an investigation without delay, and the cost of that investigation can be passed back to a leaseholder whose own shower, washing machine or dishwasher turns out to be the source. Where an independent answer is wanted, the engineer plans any thermal work around the warm floors, since they shift surface temperatures and would otherwise mislead the camera.

Golden Lane: Gas Boilers Now, Electric Systems Later

Golden Lane, raised between 1954 and 1962 and listed as well, began on a communal system and switched in the 1980s to a gas boiler or electric heating in each flat. Under the City's major works programme the gas is due to come out again, replaced by electric heating and hot water in phases across 2028 to 2035, and the estate's 16 storey tower, Great Arthur House, is pencilled in for 2029 to 2031. Until that happens, a flat with a boiler can lose pressure through a radiator, a valve or a pipe buried in a floor, so a few days of pressure readings and a look at the pressure relief pipe are the useful first move. Anything on estate pipework goes to the City Corporation as landlord.