More and more residential clients are making driveways from permeable materials. Sometimes this is due to the limitations of having a small block and ‘pushing’ the amount of hard site coverage allowable by Councils. Some clients are also keen to have as much permeable land as possible, from an aesthetic and environmentally sustainable point of view. Storm water run-off is slowed dramatically with permeable ‘soft’ surfaces in comparison to hard surfaces.
Often permeable driveways are the only way that significant trees can be retained on a site if driveways are to be renovated or enlarged, so that roots can be retained and protected whilst still getting the air and water they need.
It is becoming decidedly trendy in big cities like New York to have green driveways. Grass can be planted within plastic or concrete cells that can withstand the weight of cars.
Crushed gravel is usually placed over a compacted sub-grade which is not super-permeable, but still better than concrete. Specially designed interlocking pavers with gaps in between, which are filled with sand, are another option.
Here is a very low-maintenance green driveway that I helped design, and specified planting for, a few years ago in Palm Beach. The Dichondra and Viola grow through a concrete grass cell paver system. The plants get crushed occasionally but are so tough and fast-growing that they spring back quickly.
I have also noticed some other successful ideas on my travels. This timber sleeper driveway isn’t one of my designs, but I admire it for its simplicity and cost-effectiveness. The timber sleepers are embedded in soil and mulch – easy and cheap for a casual look.
The concrete pavers in the photo below (also not one of my projects) must have been laid on a strong foundation, and the gravel infill is permeable. The mondo grass is not looking too great where it is driven over but it looks great softening the sides.
I am looking forward to designing and installing more green driveways and softening up our urban environment.