Party Wall may be used in 4 different legal senses
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Drain Survey

The drains within the property are the responsibility of the owner.  Drains become a sewer when they are jointly owned and pass under a number of properties – this is common in London. 

The drains discharge into the main sewer on the road and the main sewer
is required to be ventilated by a soil and vent pipe, if this is cast iron it may rust

Incorrectly fitted air admittance valves can cause syphonage
and stench to enter the property

Inspection chambers allow inspection and rodding of the soil drainage system.  

If the length to diameter ratio is incorrect or the pipe run too long
syphonage will occur which will empty the traps and stench will enter the
property.

When running and testing internal drains pipes gurgling noises are indicative of inadequate traps or inadequate drainage design and installation 

Party Wall Surveyor serving Thanet and London

Third Surveyor serving England and Wales

Image of Bruce Spenser MSc MCIOB
Bruce Spenser MSc MCIOB