Soakaway size?

[Dankraut]

Could anyone let me know the size of soak away needed for a detached house (14m long x 6m wide 45 degree roof pitch all approx) I have one down pipe at front, and one at the back of house. House is approx 45 years old and although the pipes to the soak aways are clear, they can't seem to cope with the heavy rainfall so I assume they are silted? Cheers.

 

[RedHerring]

A simple formula ia
Soakaway Volume=Area to be drained X (Rainfall Rate/3000)

So assuming an area of about 117 square metres (about 8.4 meters X 14) and typical rainfall rate for UK of 50mm/hour
We have a requirement of about 2 cubic meters for the soakaway.

But that does not take into consideration your ground conditions, the water table height or the construction of the soakaway, e.g. full of rubble will reduce the volume available for water.

 

[Dankraut]

A simple formula ia
Soakaway Volume=Area to be drained X (Rainfall Rate/3000)

So assuming an area of about 117 square metres (about 8.4 meters X 14) and typical rainfall rate for UK of 50mm/hour
We have a requirement of about 2 cubic meters for the soakaway.

But that does not take into consideration your ground conditions, the water table height or the construction of the soakaway, e.g. full of rubble will reduce the volume available for water.

Thanks very much to you, had to get my teenage son to work out the formula DuuuuuuuuuH so I now know how many soak away crates needed..Thanks again.

 

[noseall]

We dig ours about 4'-6" square, as deep as a mini digger bucket will dig and fill them with all the knock-out rubble from the job.

Not had a complaint yet.

They also need to be a minimum of 5m from any structure.

If you have clay sub-soil then forget it.

 

[jono_h]

Have a chat with the Building Control department at the Council. Round our way there are usually happy with a metre by a metre by a metre deep.

 

[Chukka63]

but that doesnt mean a metre from ground level.its the size of area of you rubble etc.also depends on ground conditions entirely.