Damp proofingin Wembleyextensions, lofts and landlords

Because so much of Wembley's housing has been extended or had a loft converted, a large proportion of the damp we survey here started with building work rather than an ageing damp proof course. A rear extension roof pitched too shallow, an abutment flashing built without a proper upstand, or a new floor level set tight against the original wall can all let water in that shows up as damp on the original structure.

Loft conversions add their own set of junctions: dormer cheeks, valley gutters and rooflight flashings all need to be detailed correctly, and when they are not the resulting damp appears at ceiling level in the rooms below, sometimes well away from where the actual defect is.

Diagnosing this correctly means looking outside at the roofline and junctions as much as inside at the plaster, which is why the survey covers both before any treatment is proposed.

Sudbury retains a stock of older Victorian and Edwardian solid-wall terraces predating the interwar building boom that filled in the rest of Wembley. Where these have a failed or missing damp proof course, symptoms are the familiar tide mark, salt bloom on the plaster and soft, crumbling skirtings.

Treatment is an injected chemical damp proof course using an accredited Sovereign or Wykamol system, followed by removal of salt-contaminated plaster and replastering with a salt-retardant render and skim. As elsewhere, bridging from raised ground levels or render carried past the DPC line is checked for first, since it can be a much smaller fix.

Garage conversions are common across Wembley's semis, particularly in Tokyngton and Preston Road, and were rarely built to habitable standards, no damp proof membrane under the slab, no DPC in the walls and a floor level lower than the rest of the house. Putting that right can mean a damp proof course, tanking to the lower wall, and a correctly insulated and membraned floor.

Around Wembley Central and Alperton, where many houses have been converted into flats or let as HMOs, high occupancy and restricted ventilation regularly produce condensation and mould that gets mistaken for rising damp. We diagnose this in writing at survey, since treating condensation with a chemical DPC changes nothing, and landlords and agents need a clear answer on which they are dealing with.

The high-density flats built around Wembley Park and the stadium in recent years are constructed very differently from the surrounding streets, with cavity walls, mechanical ventilation and balconies. Damp here is more often penetrating, at balcony thresholds, render-clad elevations or window reveals, or condensation linked to under-used mechanical ventilation, rather than rising damp, since there is no solid wall or old DPC to fail.

We survey these on the same basis: establish the actual route the water is taking before recommending anything, and identify where responsibility may sit with a managing agent rather than the leaseholder.

Across Wembley's terraces and semis, cracked render, spalled brick, eroded pointing and failed sill or drip details are common contributors to damp, particularly on the more exposed flank walls of end-of-terrace and corner properties. We repair and renew render, repoint in a compatible mix, replace damaged brick and reinstate proper drip details, using helical brick stitching where cracking needs a structural repair rather than surface filling.

We cover all of Wembley, Wembley Central, Wembley Park, North Wembley, Sudbury, Alperton, Tokyngton and Preston Road, and work outward into Harrow, the wider Brent borough, Middlesex, West London, London, Watford, Slough, Buckinghamshire, High Wycombe and Surrey.

Calls are taken Monday to Friday 8am to 8pm and Saturday 8am to 1pm, with Sunday closed, and evening survey slots are available for landlords and tenants who need access arranged around work.