Flat Patios Bassendean

The Bassendean townsite was settled early and it shows. Around Old Perth Road and the streets running down toward the river there are Federation and interwar houses that predate most of the surrounding suburbs by decades.

That age brings unknowns at the fixing point. Wall construction, the condition of the mortar, whether the rear of the house is original, and what a previous owner did when they added a laundry in 1974.

None of that rules out a patio. It just means the structure gets looked at properly before we commit to an attachment method, and freestanding stays on the table as the clean solution.

Eden Hill and Ashfield read differently. Eden Hill is mostly postwar and later, on regular blocks with straightforward fascias, and Ashfield mixes surviving older cottages with newer builds on the low ground toward the wetlands.

The Town of Bassendean maintains a heritage list and applies character guidance across the older parts of the townsite, where a good deal of the original streetscape survives.

For a rear patio the controls are usually not the obstacle people fear. What is protected is largely what the street can see, and a low roof at the back of the house sits well outside that view.

The check is still worth doing first. If the dwelling carries its own listing, the design conversation, the fixing method and sometimes the roof colour are settled before a permit application is lodged.

On the higher ground the Bassendean Sand is deep, grey and free draining. Easy to excavate, excellent for stormwater, and short on the lateral support a post would like, so footings rely on depth and mass.

Closer to the river the profile changes to clay-bearing alluvium. Reactive, slower to drain, and carrying a different site classification for the footing design.

The awkward part is that both can occur within a few streets of each other. That is a good argument for a site inspection over a phone quote, because the ground under your particular block sets the price of the footings and the soakwells.

Old fill adds a third possibility. In a townsite this age there are demolished sheds, brick rubble and filled hollows under plenty of backyards, and a footing sometimes has to pass through that layer to reach undisturbed ground below. It is a common finding rather than a rare one.

Ashfield Flats is a low-lying wetland system on the river, and the land around it behaves accordingly. Winter groundwater sits high and the soil is not in a hurry to accept more.

For a patio that changes the stormwater strategy. A deep soakwell in ground that is already saturated has nothing to give, so the design shifts toward shallower, wider capacity placed above the seasonal water level.

Where the overflow goes also has to be deliberate. On flat, low ground, water that leaves an overwhelmed soakwell will find the lowest point on the block, and that should not be the back door.

A patio is Class 10a work, so the Town of Bassendean requires a building permit before construction begins. The pack includes a site plan, elevations, structural engineering and a stormwater design matched to the soil.

As with every WA local government, the Class 10a application can be lodged uncertified for the town to assess, or certified with a certificate of design compliance from a registered building surveyor.

Properties close to the Swan may also sit within the development control area under the state legislation covering the Swan and Canning rivers. Where that applies, a referral runs alongside the council process and it is better planned for than discovered.

There is a design decision here beyond the engineering. A crisp horizontal Colorbond plane against a 1920s brick and iron cottage can look either deliberate or accidental, and the difference is in the detailing.

What generally works is honesty. A clearly modern structure, set back from the original roofline, in a colour drawn from the existing roof or the window joinery rather than trying to imitate the period.

What generally does not work is decoration. Mock brackets and applied trim on a new steel structure read as a costume, and on a genuine heritage streetscape they date faster than the plain version ever will.