September 16, 2026

Interwar Semis in Twickenham, Ealing and Hounslow: Wall Ties and Condensation

Large parts of Middlesex, from Twickenham and Whitton to Ealing, Hounslow, Harrow and Pinner, were built up in the 1920s and 1930s. These family homes are well built, but at around a hundred years old, some common problems are showing.

Corroding wall ties

Many interwar cavity walls used mild steel wall ties. As they rust, they expand and can crack the outer wall. Look for horizontal cracks in mortar joints every few courses, bulging brickwork and lifting window sills.

Condensation in extended homes

Extensions, loft conversions, new windows and draught-proofing all make homes warmer, but they also reduce natural ventilation. Kitchens and bathrooms without good extraction lead to condensation and black mould, especially in bedrooms.

Suspended floors and air bricks

Interwar homes usually have suspended timber floors, ventilated by air bricks. When air bricks are blocked by raised paths, extensions or rendering, the void beneath becomes damp and timber decay and woodworm can follow.

Bridged damp proof courses

Driveways, patios and paths laid over the years often sit too high against the walls, bridging the damp proof course and causing damp at low level.

A health check for your home

  • Walk round outside and check the air bricks are clear
  • Make sure paths sit at least 150mm below the damp proof course
  • Look for repeating horizontal cracks in the brickwork
  • Check bathrooms and kitchens have working extraction

Middlesex is just across the river from our office. See wall tie replacement in Middlesex and condensation control in Middlesex.

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