Terraced house survey: party walls, shared drainage, and what to check

What makes this property type distinctive

Most UK terraces are Victorian or Edwardian, with later inter-war and post-war additions. Solid brick is universal in pre-1920 stock; cavity from the 1930s onwards. Party walls are typically loadbearing on Victorian terraces. Chimney stacks often straddle the party wall, with each property owning one flue. Shared drainage is common and now mostly transferred to public ownership under the 2011 Water Industry regulations.

Common defects to expect

These items are routine for the property type. Most are renegotiation items, not deal-breakers. The survey's job is to flag which apply to this specific property and which have already been addressed.

• Chimney stack movement at the party wall
• Damp in party walls (sometimes from the neighbour's plumbing)
• Shared drainage condition where private
• Bay window settlement at the front
• Lath-and-plaster ceilings cracking
• Slate roof end of life and shared with neighbours
• Single-skin rear extensions or outhouses
• Sash window decay (Victorian/Edwardian terraces)

What the survey should cover

• Party wall condition: cracks, dampness, evidence of work without consent
• Chimney stack condition where shared
• Roof structure including any spray foam, sarking felt, and the boundary with neighbours' roofs
• Drainage: public sewer or shared private; CCTV survey if old clay
• Bay window settlement (very common, usually historic)
• Solid wall damp diagnosis

Which survey level to book

RICS Level 3 (Building Survey) for any pre-1940 terrace. Level 2 only for well-kept post-1980 terrace housing with no visible alterations.

For a deeper comparison see Level 2 vs Level 3 survey.

Construction-specific risks

Party walls and shared structures introduce risks the buyer can't fully assess from inside their own property. Neighbour-driven damp, neighbour-driven structural movement, and shared drainage failures are all routine. The Party Wall etc. Act 1996 governs works affecting party walls, historic non-compliance is sometimes flagged on surveys.

What to check before offering

• →Read the party-wall situation: which walls are loadbearing, who owns each chimney flue
• →Confirm whether drainage is public or shared private
• →Check whether any extensions had Building Regs and Party Wall consents
• →Read the EPC, terrace properties often have lower EPCs due to wall-to-volume ratio (good) but solid walls (bad)

Use the full pre-offer checklist on the house buying checklist to combine these property-type checks with the standard pre-offer items.

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Frequently asked questions