A 48 metre long shared water supply pipe connected to eight cottages in London undergoes repair and refurbishment

London Cottages Corroded 48 Metre Long Shared Water Supply Pipe Leak Repair

Four cottage owners from a terrace of eight in London opt to repair their respective sections of a 48 metre long shared water supply pipe attached to the back of the building after low-quality lagging trapped moisture against the steel line, leading to heavy corrosion and numerous leaks.

Case Study Overview

Site 19th century cottages
Location London, UK
Pipe Type 50mm steel shared water supply pipe
Repair Type Leak repair and pipe reinforcement
Products Superfast Aqua PW Epoxy Putty, Liquid Metal Epoxy Coating, SylWrap Pipe Repair Bandage

Pipe Defect

The row of eight terraced cottages were built in the middle of the 19th century. They were connected to the public water network at a later date via a somewhat unusual setup involving an above-ground shared supply pipe.

This pipe connected with a water main at one end of the terrace. It then rose up the side of the first cottage, from where it was fixed at a height of three metres across the back wall of the eight cottages.

It ran for 48 metres, surrounded by building extensions, downpipes, guttering, satellites and other installations added to the cottages over time.

Because it was a shared supply pipe, the local water company bore no responsibility for the line. It was instead down to the cottage owners to repair and maintain the pipe collectively, or to look after the section of around six metres behind their respective property.

After temperatures in London dropped to -8°C, one of the cottages noticed their section was leaking. Lagging was removed to access the pipe, revealing several cracks and severe corrosion across the entire line.

The lagging was discovered to have been low-quality material which soaked up moisture, trapping water against the steel pipe and causing heavy corrosion. The cracks were a result of the weakened metalwork being unable to cope with the freezing weather.

It was inevitable the other seven cottages were going to suffer leaks in their own sections in the not-too-distant future. With this in mind, they looked into replacement options.

Total replacement of the entire 48 metre line was quoted at £22,000. Some cottages did not want to contribute £2,750 towards this, instead preferring to chance their six metre section would not deteriorate further.

Replacing individual sections for those wanting to avoid future leaks was not practical. The work would be too disruptive and new fittings would struggle to connect with the old, brittle sections not being replaced.

With no common route forward, the cottage with the leaking section contacted Sylmasta asking for advice to repair their part of the shared water supply line.

SylWrap Solution

The Sylmasta Pipe Refurbishment System was used to seal the leaks, reinforce the pipe and protect against further corrosion. With two cottages requesting their sections be attended to, Sylmasta sent an approved contractor to carry out the application.

Lagging was removed and all the holes sealed with Superfast Aqua PW Epoxy Putty, chosen for its excellent wet surface adhesion amid concerns the pipe may have been weeping. Superfast Aqua PW has WRAS Approval, meaning it is certified as safe for contact with drinking water.

Enough putty was cut from an Aqua PW Stick, kneaded by hand and then pushed into a hole. Within 20 minutes, it cured to form a rock-hard sealing material. Once every hole had been filled, the two sections of pipe being repaired were painted with Liquid Metal Epoxy Coating.

Liquid Metal formed a new, hard-wearing metallic outer surface around the pipe to refurbish the weakened steel and act as a shield against external corrosion. Should the brittle metal be breached from inside, the Liquid Metal shell would also contain the pipe contents.

Four layers of SylWrap Pipe Repair Bandage were added next. SylWrap was wrapped around the two sections being repaired, encompassing them in an impact resistant shell. SylWrap application took place whilst the Liquid Metal remained tacky, improving adhesion between the pipe and the Bandage.

Finally, better quality lagging was installed. Even if moisture again became trapped by the insulation, Liquid Metal and SylWrap would prevent any water contact with the original pipe.

Superfast Aqua PW Stick used to repair a leaking shared water supply pipe in London
Superfast Aqua PW Epoxy Putty sealed all holes in the pipe


After watching the repair process, a third cottage asked for their section to be looked at. Corrosion was yet to breach this area of the pipe, meaning only Liquid Metal and SylWrap Bandage were needed to strengthen the section.

All three cottages were completed in a single day. A fourth cottage then requested Sylmasta revisit for their section. Once completed, it meant the Sylmasta Pipe Refurbishment System had reinforced half the 48 metre shared water supply pipe with a repair which will last many years.

Follow Up

Around a year after the initial repair, a fifth cottage contacted Sylmasta. 12 months of further corrosion had caused numerous cracks and left their section of the pipe on the verge of collapse.

Because of the condition of the pipe, a repair was now far more challenging and costly than the refurbishment the other four cottages opted for – highlighting the benefits of strengthening and protecting systems before serious problems develop.

Products Used

Superfast Aqua PW
WRAS approved epoxy putty which seals holes and cracks in pipes where the surface is wet

Liquid Metal
Epoxy coating painted onto pipes for refurbishment and protection against corrosion

SylWrap Pipe Repair Bandage
Water-activated wrap sets rock hard to reinforce and strengthen repairs

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