Percolation Test

[faye.giannotti@gmail]

Hi, can anyone help confirm who is responsible for ensuring that a percolation test is carried out following a Building Control inspection? Should this be included in the Architects' drawings to be done or down to the Builder?

 

[freddiemercurystwin]

Typically a structural engineer wold be employed to check the test is adhered to ie he'll stand there and look interested for an hour or so, charging you the earth for it (no pun intended). That said, it's quite common for BCO's to be familiar with your local area soil conditions and may suggest a size that will typically work.

 

[faye.giannotti@gmail]

Thank you for your reply. Very helpful and much appreciated.
A structural engineer has been employed to provide calculations however, they have not stated that a percolation test should be carried out. BC has requested that this be done.
Should the structural engineer have stated this in the first instance for the builder to then carry out?
I'm trying to identify whose responsibility for this to be done.

 

[freddiemercurystwin]

Well normally a percolation test is not required, (assuming we're talking about a domestic extension?) and as mentioned BC usually know the lay of the land so an SE wouldn't expect to be drawn in to overseeing a test. Neither would a builder. However if BC are insisting on a test you'll have to suck it up, ordinarily the process involves the builder digging a specific sized hole, pouring in a measured amount of water and then the SE standing there until the level drops by a measured amount, then he can calculate how the soil drains and work out the size the soakaway needs to be after calculating the amount of rainfall it's expected to cope with.

Or if you have a Google you may find a local drainage/soakaway company who can do it, may or may not be less expensive than using an SE, who's hourly rate is likely to be seemingly absurd.