Have a large driveway comprising 300m sub-base (heavy vehicles) and 50mm overlay of gravel. Ground is slightly boggy so will be having filter drains each side to protect the subgrade and terram 2000 permeable surround beneath sub base to stop washdown.
Would you recommend type 1 sub base or type 3 sub-base for the base layer, heard type 3 is the more permeable but would have thought type 1 should suffice, given that its widely recommended for use on gravel driveways, there may be issues of trickle down of the gravel into the type 3 as it has no voids but not sure....any ideas...would compacted type 1 be permeable enough to allow water to drain down into the sub-grade without it turning to porridge?
Thanks