Flat Roof Patios in Byford

The estate housing is the volume end. Project homes on small to medium lots, an alfresco already under the main roof, and a yard people want extended and covered.

The older Byford stock is looser. Weatherboard and brick homes on generous blocks around the townsite, some with sheds, fruit trees and gravel driveways still in place.

Out at Cardup, Oakford, Karrakup and Darling Downs it is rural residential. Hectares rather than square metres, and a patio that has to work as the only shade near the house.

The plain south of Armadale carries some of the heaviest clay in the metropolitan area. It holds water at the surface, stays wet long after the rain has stopped, and dries into a hard crust in summer.

Soakwells are the part that catches people out. A well dug into clay that will not accept water is a storage tank, not a drainage system, and it will be full when the next storm arrives.

So the design goes bigger, or wider, or shallower into whatever permeable layer sits above the clay. Where the ground genuinely will not take it, the answer is a different disposal strategy agreed with the shire.

Reactive clay swells and shrinks through the year, and the movement is concentrated in the upper soil. A patio footing sitting in that zone gets lifted and dropped every season.

The engineer designs against the site classification for the block, not against a generic table. On the heavier Byford soils that generally means going deeper to get below the active zone.

It is also why the site inspection is not a formality here. Two blocks in the same street can classify differently, and the footing schedule follows the block.

On a rural residential block at Oakford or Darling Downs, nothing is competing for space. The patio can be as large as the budget allows, freestanding if that suits, and oriented to the view rather than the back door.

Access is the real constraint. Long gravel driveways, gates and turning circles decide the maximum sheet and beam length that can physically get to the build area.

Unsewered properties add a check. Where a septic system and leach drains are in the yard they need locating first, because you cannot put a footing through one or roof over the disposal area.

Wind classification depends heavily on what stands upwind slowing the air down. A new Byford estate with low fences and young trees, or a paddock-edge block with nothing between it and the horizon, offers very little of that.

So the assessed rating can come back higher than an established suburb would give you, even though this is inland wind rather than coastal. Perth is wind region A either way.

A higher rating means more structure. Larger posts, deeper and wider footings, tighter purlin spacing and more fixings per sheet, all of it set by the engineer against the number for your address.

The eastern edge of the district climbs into the Darling Scarp and the character changes quickly. Slope, gravel, rock and mature bush instead of flat clay paddock.

Bushfire mapping covers a good deal of that country, along with the surrounding shire out toward Jarrahdale and Serpentine. Where the designation reaches your address, the construction standard follows the level assessed for the site.

It is an address check rather than a suburb assumption. The state bushfire prone areas map is the reference, and it is worth looking at before the design is settled.

A patio is Class 10a work, so a building permit from the Shire of Serpentine-Jarrahdale is required before construction begins. The application needs a site plan, elevations, structural engineering and a stormwater design suited to the clay.

It can be lodged uncertified for the shire to assess, or certified with a certificate of design compliance from a registered building surveyor.

Rural and rural residential lots run under different planning provisions to the estate lots. Setbacks, site coverage and outbuilding rules are worth checking against the local planning scheme before the design is locked in.

Bushfire adds a step where the mapping applies. Depending on the proposal a bushfire attack level assessment may need to accompany the application, and the construction standard follows from it.