Building Construction Handbook, Eighth Edition

Party Wall ~ a wall separating different owners buildings, ie. a wall
that stands astride the boundary line between property of
different ownerships. It may also be solely on one owner's land but
used to separate two buildings.

ridge

eaves

upper

floor

boundary line

ground

floor

party wall between dwellings

functions as a separating wall

for sound insulation and for

fire compartmentation

fire stopping in boxed eaves

ct/s mortar or mineral wool

fire stop between separating

wall and underside of roof tiles

Where an internal separating wall forms a junction with an
external cavity wall, the cavity must be fire stopped by using a
barrier of fire resisting material. Depending on the application, the
material specification is of at least 30 minutes fire resistance.
Between terraced and semi-detached dwellings the location is
usually limited by the separating elements. For other buildings
additional fire stopping will be required in constructional cavities
such as suspended ceilings, rainscreen cladding and raised floors.
The spacing of these cavity barriers is generally not more than
20 m in any direction, subject to some variation as indicated
in Volume 2 of Approved Document B.

Refs.
Party Wall Act 1996.
Building Regulations, A.D. B, Volumes 1 and 2: Fire safety.
Building Regulations, A.D. E: Resistance to the passage of sound.

Internal Party Walls