Drainage and Planning Permission Information From Surrey Driveways
Always seek advise from your local building control department before starting work on your driveway soak-away.
In October 2008 government Planning permission changed on the way you design the rainwater run off from your new driveway ( Link to the planning regulations ).
In short you are no longer allowed to disperse the rainwater from your driveway onto the public highway if the area being paved exceeds 5qm2.
There are several solutions you can use to comply with the new planning regulations, these can be permeable paving or permeable tarmac, gravel, a large enough area of lawn or flower bed to drain onto or as we show in the photos, soak-away attenuation crates, these work on the principle of excavating a large chamber under the driveway or lawn, placing the attenuation crates into the excavated chamber and connecting your drainage system.
Step 1: Decide where the best place to excavate the soak-away chamber will be, there is a rule off thumb that a soak-away should be 5 meters away from any building ( you should seek advise from your local building control department if you are unsure )
On this driveway Surrey-Driveways excavated down to 1.4 meters and allowed a clearance of 100mm around the crates.
Stage 2: For this driveway in Crawley the soak-away required 3 crates, the crates are stacked on top of each other, then using cable ties connect the crates together, this prevents the crates falling apart when lowering them into the chamber.
Stage 3: Using a Geo-textile membrane or Terran completely rap the crates and tape the loose folds with duct tape, this is to prevent the 20mm gravel and silt filling the crate voids.
Stage 4: Take care to level out the bottom of the chamber so the crates sit level, then lower the covered crates into the chamber, the top of the crate should sit about 5 or 6 inches below ground level, this is to allow for the concrete slab which will cover the crates.
Stage 5: Fill the cavities around the soak-away crates with a 20mm gravel and consolidate.
Stage 6: Connect the rainwater pipes and linear surface drains into the crates, this is done by slicing the Geo-textile and cutting out a hole in the crate large enough to drop the 4" drainage pipes into.
The top of the crate is then filled with a wet concrete mix 5 or 6 inches thick.
Stage 7: The new surface can now be laid over the soak-away to conform with the new driveway drainage planning permission.