Permeable paving and carport

Creating the car parking area for 23B was next on the landscaping to-do list after we finished the backyard at 23A.  At the back of this spot stands our grand old Swamp Gum. Selecting a suitable permeable paving is crucial to protect the tree’s root zone.  Another decision is working out an appropriate carport design to protect two vehicles from the weather.

Let’s start with the carport.

Carport is a unique design.

With construction underway, the carport site was hard to spot amidst piles of dirt, machinery and delivered materials.

Right from the start, Libby and David were tossing around ideas for an open structure based on two central supports.  The roof would soar above the ground with reclaimed timber strips linking the design to the timbers used on 23B.  The idea was to enhance the entrance way, instead of closing down the view with a boxlike garage.

After the sturdy central support posts went in, visitors knew this was not an ordinary carport.  One visitor actually thought it was a communal BBQ area.

David selected the timbers from Recycled Timber Specialists in Kinglake Central.  It’s old growth hardwood that looks as thought it spent many years holding up part of a large shed somewhere in Melbourne.

Next came the roof framework.  The design reminded me of the balsa wood wings on the model aeroplanes I built as a kid, just before I applied paper and doping glue.

A mixture of clear and steel panels stops the roof from obscuring the view of the Swamp Gum.

The site was now ready to pave the parking area.

Exploring permeable paving options.

Permeable paving is essential for letting rainwater soak into the ground above the tree roots and to allow the soil to “breathe”.  Since the Swamp Gum is a significant canopy tree, we wanted to look after its health so it continues to attract the local birdlife.

There are many permeable paving options on the market, each with their own selling points.  Installed costs vary widely.

Pavers Plus supply two types of specialised pavers for this purpose.  Adbri Ecopave have specially designed gaps that allow rainwater to permeate between the pavers.  The Adbri Turfgrid(R) is a design we’ve seen used on local driveways.  The paver is a lattice of holes that are filled with soil for growing a groundcover or grass.  This offers the potential for a natural, grassy surface with a subsurface vehicle support.

Plastic paving such as Cirtex SurePave (from Bunnings) and GEOHEX (TM) Erosion Control System (from Melbourne Brick) does a similar job.  The cells in a paving sheet hold screenings or soil/grass in place which means car tyres don’t cause unsightly ruts. Making the permeable paving system from recycled and recyclable polypropylene is a plus. I like seeing recycled plastic actually being used for something, instead of being stockpiled in warehouses all over Australia.

Porous pavers are available.

Next step up the paving ladder is ceramic permeable pavers such as HydroSTON.  Rather than go around the edge of the paver, water drains straight through because the they’re made from porous concrete. You can go one step further with Premier HydroPavers which use a porous structure made from recycled ceramic wastes.  Again, another good example of manufacturers closing the recycling loop.

Based on my research, the top of the ladder is a company like New Dawn Permeable Paving laying a resin-bonded aggregate on a permeable concrete base.  No need to worry about individual pavers moving about because it’s one continuous surface.

We chose ECOHEX permeable paving.

After considering performance and installed cost, we chose ECOHEX paving for the carport.

Dan from Terra Firma Creations started by laying a porous base of screenings and sand.  We used “no fines” materials to avoid small particles clogging the drainage path.

Next job is laying out the panels.  Each one clicks together with its neighbours, forming a strong base.  Being plastic, they were easy to cut to fit along curves and around the base of the carport supports.

The hexagonal cells in the EcoHex sections are filled with 14mm screenings from Eastern Suburbs Garden Supplies.  We chose this size as the rocks are small enough to easily pack into the cells but too big to get caught in the soles of your shoes.  Tracking small rocks into the house would be annoying.  Also, the plain colour is a good backdrop to highlight the timber of carport structure.

A 21st Century addition.

Hidden away behind the rear support post, lurks a useful sustainable home feature. This is the spot for connecting electric vehicle chargers.

We took the opportunity to future-proof our EV charging points. The top connection is the standard 15A circuit for trickle charging the Nissan LEAF at 3.7 kWh .

Underneath is a 3 phase outlet that will come in handy when we replace the trusty old diesel Golf with a current model EV. Newer models have larger batteries so we wanted the facility to fast charge for longer trips.

Who knows, in the future there might be a Tesla sitting in the carport? Having the 3 phase outlet running at 22 kWh cuts charge time from 21 to 5 hours. A boy can dream …

End result fits the bill.

The result is just what we wanted.

A light, airy open structure enhances the view of the Swamp Gum while providing plenty of room for our cars.  Permeable paving protects the tree roots while delivering a good driving surface.

Timber highlights on the carport roof complement the timber supports above the front entrance and blend with the board & batten cladding on the wall.  Anybody might think there was some sort of master plan to create this effect.

I added the finishing touch on the carport area by putting the cow and calf sculpture on the side fence.  They’ve been with us for many years, including the last couple of years hiding away behind a pile of construction timber.  Now they are back on display, welcoming us home.

All in all, the carport was a pleasing addition to the landscaping of 23B.

• landscapingUnit 3