Soakaway question (yet another one!)

[RonnyRaygun]

I've just built a small (3m x 3m) extension to the rear of my property. I am also planning to install a conservatory of the same size.

I was told by my building inspector to dig a 1.2m3 hole for a soakaway.

First question. Do I really need a hole that size? I did the calculations and I reckon using Aquacell or similar I could drain three times the area into a hole that size.

Second question. Do I need an inspection hole?

Third question. I've read in a few places that I need to be at least 2.5m from any boundary. My garden isn't big enough to stay that distance from a boundary while also being 5m from my extension. The building inspector doesn't seem worried by that so I suppose it must be OK.

Thanks for your help.

[lutonlagerlout]

1 metre cubed below invert level is the minimum sized soakaway that most local authorities allow, so in effect this must be a metre by metre square hole ,1.2 deep to allow for the pipe and some cover of soil over the crates or hardcore.
5m is the minimum length they like and in an ideal world 2.5m in from the boundary but the 5 m from the house is more important

inspection hole??
what for ??
its only rainwater going in to it

IMHO its worth using a trapped gulley to stop leaves and detritus from getting down and blocking the pipe/soakaway

regards LLL



Edited By lutonlagerlout on 1251827347

[Tony McC]

I think most BCOs still think of soakaways as rubble-filled amorphous holes in the ground, with, at best, 30% void space. Using crates achieves 95-98% void space so, in theory, a soakaway need only be one-third the size (soil permeability assumed to be good).

You could ask the BCO to explain how they came up with that rather convenient figure. What's the betting that it's "what we always use"?

[lutonlagerlout]

under a certain meterage of roof you dont need any soakaway.
sadly for ronald i think its 4.5 m 2
regards LLL