Damp Proofing St Pancras

The streets around St Pancras and King's Cross have seen more change than almost anywhere in London over the past twenty years, but behind the new developments the area is still full of older buildings. Georgian squares and terraces such as Argyle Square, Regent Square and the streets around Cartwright Gardens sit just south of the stations, Victorian terraces and mansion blocks run north towards Camden and Somers Town, and the canal side has a mix of warehouse conversions and new apartment blocks around Granary Square and Coal Drops Yard.

The Georgian and Victorian buildings almost all have basements with front lightwells and vaults beneath the pavement. These are the source of a large share of the damp problems we see in NW1 and WC1. Lower ground floor flats suffer from groundwater against the walls, water entering through vault roofs and lightwell junctions, and bridged damp proof courses where lightwell floors have been raised. Making these spaces properly dry needs a waterproofing system designed to BS 8102, usually a cavity drain membrane with drainage to a sump and pump, rather than the coatings and slurries that were often applied in the past.

Higher up, the period terraces have hidden roofs behind parapets, with parapet and valley gutters that easily block with leaves and debris. When they overflow, water runs into the top of the walls and appears as damp patches in top floor flats, sometimes several rooms away from the actual leak. Failed pointing, cracked stucco and defective downpipes cause similar problems on the front and rear elevations.

Being next to two of the busiest railway termini in the country has its own effects. Some railway adjacent buildings show cracking in render and masonry, which lets rain in, and buildings with walls close to the tracks can be harder to maintain, so small defects are often left until they become damp problems inside.

Many of the buildings around Argyle Square, Regent Square and the Bloomsbury edge are listed or within conservation areas. Repairs need to respect the original lime based construction, so we favour breathable plasters and renders, sympathetic masonry repairs and drained membrane systems below ground that can be installed without harming historic fabric.

In the converted flats and the new build blocks, condensation and black mould are the most common call outs. Converted flats often have small bathrooms and kitchens with limited extraction, while new apartments are well sealed and can build up humidity quickly. We also investigate leaks between flats and water ingress at balconies and roof terraces in the newer developments.

A large proportion of homes around St Pancras are rented, including student accommodation and housing association properties. Our surveys give landlords and managing agents a clear diagnosis, set out who is responsible for the repair and provide a written specification, so issues reported by tenants can be resolved quickly and properly.

We also carry out pre-purchase damp and timber surveys for buyers of period flats around St Pancras. A valuer's note about damp in a lower ground floor flat can mean many things, and our report explains what is really happening, whether the problem belongs to the flat or the building, and what any repair will involve.

Our London office on Fitzroy Street is less than a mile away, so we can usually survey in St Pancras and King's Cross within a few working days.