High temperatures and the current drought gripping much of Australia are likely to lead to a fierce bushfire season this summer. The massive garden makeover undertaken at this home on the fringes of the Sydney basin showcases some practical ways to help protect properties against bushfires.

This house has been rebuilt by the owners to replace the home they lost in the 2001 Christmas fires. The site has many constraints including its location at the head of a gully on a west facing slope - a very high risk place to build in a bushfire area. No town water is available - all water is collected from the roof of the shed in a concrete rainwater tank. A site visit from the NSW Rural Fire Service highlighted issues that required specific consideration in the landscape planning and construction of the new garden.

Andrew Davies, from dig , has taken the bushfire threat into account in his design for a contemporary homestead that sits well within its natural setting. The use of non-combustible materials for all structural elements was the premise of the design. Sandstone boulders and sawn sandstone flagging was used in all retaining walls and pathways, while a steel-framed deck supports fibre cement sheeting and steel grated gangways. Plantings of vegetation high in moisture content help to deflect heat, while pebble and granite mulches form a protective zone around the house.

Additional water storage, a rooftop misting system and a petrol-powered pump have all helped to protect this home against future onslaughts from bushfire.
Front Plan
Back Plan

Getting started

Two bobcats, an excavator, two mini-loaders and numerous sets of hands were required for this huge makeover. An initial site clean-up and excavations for sub-base levels were undertaken, leaving the task of transporting materials to each project location at the start of the first day.

Materials  

Retaining walls: Nigel directed the bobcat in its placement of large sandstone boulders and some smaller boulders to create an informal sandstone retaining wall. The careful placement of a row of boulders and partial backfilling with blue metal enabled another row of boulders to be placed on top. The weight of the boulders and their positioning will hold them in place. Blitz Tipz: Large diameter, granular backfilling material will allow water to move freely from behind the wall and prevent the likelihood of the wall overturning or collapsing. Sandstone steps: Nigel and the landscape team from 'Location Location' built a set of formal stairs leading from the front verandah to the front gate. Common extruded bricks were laid into a mortar footing to provide a solid framework to the steps and enable accurate riser and tread ratios to be created. Sawn sandstone was laid on a bed of mortar providing a formal veneer for the risers and treads. The gaps between the sandstone pieces were pointed with a 3:1 sand and cement mix and all excess mortar was removed with fresh water and a sponge. Blitz Tipz: Standard garden steps have 180mm high risers and 350mm deep treads.

Sandstone pathways: a 100mm-thick layer of roadbase was compacted to provide a solid, level sub-base to 2 styles of sandstone paving. To continue the formal theme of the new steps, sawn sandstone was laid on a level bed of mortar and finished with the same mortar joint as the steps. Sandstone flagging laid onto a bed of mortar runs parallel to the verandah. Nepean River pebbles (20-40mm) were swept between the flagging pieces to help link the path with the garden (see pic above). The pebbles were also used as a free-draining mulch in this low point of the front garden. Blitz Tipz: Any decorative material can be used as a mulch, as long as it stays in place and helps to retain moisture and reduce weed growth.

Decking: the bushfire-prone location required the entire deck structure to be constructed using non-combustible materials. Adjustable uni-piers were bolted into bedrock or installed in ground in rapid setting concrete (depending on the material beneath each post location), supporting galvanised steel bearers and joists. Fibre cement sheets (18mm thick) were screwed in place and painted with paving paint to provide a hardwearing and alternative style deck. A post and rail balustrade runs around those parts of the deck that are 1 metre or more above ground level. Steel walkways link the decks and provide a viewing area to the bush beyond and the animal shelters beneath. Steel grates were laid across steel bearers and bolted into place, enabling views to the water feature that divides the deck. Blitz  Tipz: Although the theory of constructing a steel deck is the same as building a timber deck, the materials and tools used are very different. Unless you are a skilled handyperson this sort of project is best left to the experts. Garden beds: Jody created new garden beds behind the low boulder walls by incorporating some crushed sandstone soil with a native soil mix from our landscape supplier. An inflammable mulch of brown, decomposed granite will help to suppress weeds and retain soil moisture. Blitz Tipz: Cut and fill styles of construction tend to leave the subsoil of the site exposed. Ask the builder to stockpile the site soil and to supervise distribution throughout your new garden area following completion of construction.
Water feature: Jamie created a spectacular, naturalistic billabong with a heavy-duty pond liner (1.2mm thick) and sandstone boulders. Designed to mimic a trickling stream, the water feature was excavated to a depth of 500mm. A liner was smoothed into the contours and held in place with large sandstone boulders, which were lowered into position by the bobcat. The water flows into an excavated low point from where it is recirculated to the top of the feature. Smaller boulders and river pebbles were used to reduce the water depth and disguise the non-kink pipes (25mm) and outlets. A large volume, submersible pump powers the water flow. A float valve on the pump automatically cuts power to the pump if the water level becomes too low. Blitz Tipz: Pond liners are available in a range of sizes and thicknesses to suit  different projects. They can also be joint welded or moulded to fit formal features. Look under ponds in the local Yellow Pages to find your nearest supplier. Front fence: a post and rail fence defines the front boundary and gives a welcoming feel to the house and garden. 200mm diameter hardwood posts were installed vertically in ground in concrete and housed out to accommodate hardwood rails skew-nailed in place. Blitz Tipz: A decorative and rustic style fence like this cost about $75 per metre.
Misting system: a misting system over the roof is an additional preventative mechanism that will help to protect the house in a bushfire. Water is forced through copper piping and outlets by a petrol powered pump to create a mist that shrouds the house and deflects the heat of approaching bushfires. This rooftop fire protection system cost about $2200 including installation and the petrol pump needed to power it.
Gutta-arma: a common entry point for embers into houses is through leaf filled gutters and eaves. Preventing leaves from entering the gutters is one way to reduce the likelihood of damage to the house in a bushfire. Don supervised the installation of a great new product called gutta-arma, which prevents leaves from entering the gutters. Gutta-arma is available to suit any roof type and colour and cost about $1500 to supply and install on the average 3 bedroom home.

Plants

Plants high in moisture content were chosen to create a garden full of form and colour, with a distinctly Australian flavour.

Trees: lilly pilly ( Acmena smithii )
Shrubs: looking glass plant  ( Coprosma 'Copper Shine'), rosemary (Rosmarinus 'Blue Lagoon')
Groundcovers: creeping boobiala ( Myoporum parvifolium), native violet ( Viola hederacea )
Perennials: verbena ( Verbena 'Peri Pink'), gazania ( Gazania hybrids)

Cost and availability

We used mature plants in our makeover to create an instant effect for television. As a result, our total cost for plants and materials was $55,604. The use of smaller plants would have reduced the cost to $49,224.

Product details

Sawn sandstone flagging costs about $125 per square metre from Kellyville Landscape Supplies. Phone (02) 9627 5775 or web www.kls.com.au for more information. Sandstone boulders cost about $70 per tonne and are available from landscape suppliers. A minimum cartage rate usually applies. We sourced all landscape materials from Turtle Nursery and Landscape Supplies in Kellyville, Sydney. Phone (02) 9629 2299 for more details on prices and product availability. BHP Lysaght supplied steel posts beams and joists for the decking. The steel component of this deck cost about $4,400. Phone (02) 4720 1900 for more details or visit the website at www.lysaght.com.au Fibre cement sheeting cost about $80 per square metre for 18mm thick sheets. Sheet sizes will affect price. Call 131 103 for Customer Information or visit the website on www.jameshardie.com.au Gutta-arma costs about $24 per metre, fully installed. Contact The Leaf Man on 1300 888 743 or visit the website at www.gutta-arma.com.au Rooftop misting system was installed by Gosford Irrigation. Phone (02) 4588 6117. Most of the plants we used are readily available at - or can be ordered from - nurseries. Nurseries can also advise on similar varieties suited to your area. You may need to contact specialist nurseries for some plants. Your local nursery should be able to provide you with contacts.  Most other materials are available from large hardware stores or building or landscape suppliers. All tools used, are commonly available for hire, including the airless spray gun and the Kanga mini excavator.

Further information

Acknowledgments
Design by dig
design - ideas - gardens
Phone: (02) 9416 6022

Construction by Burke's Backyard,
Backyard Blitz and Location Location

Copyright 2002 CTC Productions