Category House Extension

A manhole in the extension footprint rarely stops the build, but it changes the design. Private vs public drains, what AD H and Thames Water allow, and the fixes.

Building regs put a soakaway first for extension rainwater, but London's clay and small gardens often rule it out. The rules, the tests and the alternatives.

Most London home extensions never pay CIL, but extensions of 100 m² or more must claim the exemption on Form 9 before work starts. The rules in plain English.

Why kitchen extensions feel cold in winter – glazing, cold surfaces, draughts and undersized heating – what Part L does and doesn't guarantee, and what helps.

Why cracks appear where an extension meets the original house, how to judge them using BRE Digest 251, the warning signs and what to do next.

A design checklist for London terraces: how to stop a side return extension leaving the original middle room dark and unused.