Drain Alert carried out an in-situ pipe repair using a two-stage process designed specifically for corroded cast iron pipework in inaccessible locations.

First, the full internal surface of the pipe was prepared using a Picote milling machine. This electro-mechanical tool uses high-speed spinning flails to remove all internal corrosion, followed by a spinning sandpaper attachment to finish the surface to a smooth, clean profile — ready to receive the lining.

With the pipe surface fully prepared, an epoxy spray coating was applied to the interior of the 80mm diameter downpipe. The resin was built up in three separate passes of 1mm each, achieving a final lining thickness of 3mm. Each coat was then cured using a UV light rig passed down the length of the pipe, ensuring a rapid and complete cure.

The result was a completely watertight, structurally reinforced pipe repair — carried out entirely from within the existing pipework, with no excavation or disruption to the library’s walls.

The repaired pipe is now fully watertight and structurally sound, with a smooth epoxy-lined interior that will resist future corrosion. The repair was completed without any need to open up the building’s walls, preserving the fabric of this public building and avoiding the significant cost and disruption that a full pipe replacement would have involved.

This technique is particularly well suited to vertical downpipes in heritage and public buildings where the original pipework is concealed within the structure. It demonstrates Drain Alert’s capability to deliver specialist no-dig repair solutions in sensitive environments where conventional methods are not an option.