Flat Patios Canning

Three suburbs carry most of the work in this council. Willetton, Riverton and Parkwood were built out through the 1970s on regular rectangular lots, with the house sitting square to the boundaries.

That regularity is worth money at quote stage. A straight fascia at a consistent height lets a receiver channel run the full width of the patio without a step in it, and the posts land where the drawing put them.

Lynwood and Queens Park are older in parts and lower at the eaves. Fixing height gets tight on the lowest of them, and a freestanding roof set just clear of the house often gives a better ceiling height than cutting in ever will.

Roof material on the house matters as much as its age. A tiled roof of that vintage was frequently laid without sarking, so cutting in above the gutter line opens up more than anyone wants, while a later Colorbond roof gives a cleaner tie-in.

The flats through Wilson, Ferndale and Shelley carry Guildford Formation soil, which is clay-bearing and slow to accept water. Higher ground toward Willetton and Riverton is sandier and behaves nothing like it.

July shows you the difference. A Willetton lawn drains overnight, while a block near the foreshore can hold surface water for days, and that is the ground a soakwell has to discharge into.

So the drainage design follows the block rather than the postcode. Two houses a kilometre apart in this council can end up with genuinely different soakwell schedules for the same roof area.

Rossmoyne, Shelley and Riverton have seen a long run of knock-down rebuilds. The replacements are usually two storey and sit closer to the rear boundary than the house they replaced.

That is a change of attachment method, not a problem. The roof ties into the ground-floor wall below the upper storey instead of a fascia, and there is normally more height available than the original house offered.

Detailing gets stricter. A wall fix needs the right flashing, fixings into the actual structure behind the render, and a fall that carries water away from a junction now sitting under a first-floor window.

The Canning River Regional Park runs right through the middle of this council area, and properties backing onto the foreshore reserve pick up two extra questions.

Land close to the river can sit inside the development control area established under the state legislation covering the Swan and Canning rivers. Where it applies, a referral runs alongside the ordinary council approval and adds time rather than difficulty.

Low foreshore ground also sits nearer the seasonal water table. A soakwell that is already half full in August has nothing left to give a storm, so the levels get established before the layout is fixed.

The typical Willetton or Riverton back wall is long, and people want the roof to run the whole way. That raises the one structural question that decides the price of a flat patio: how far apart the posts stand.

A flat roof gives you room to move here. There is no ridge height to keep sensible, so the beam can grow deep enough to carry the span while the roof plane stays exactly where you set it.

The trade-off is worth seeing in numbers. Past a certain distance, an extra post costs less than the steel it saves, and we would rather show you both options than quietly pick one.

Where the posts land also decides how the yard works afterwards. A post in the middle of a paved entertaining area is a permanent nuisance, so we set them against the furniture layout and the path to the shed before the beam is sized.

A patio is a Class 10a structure under the National Construction Code, so a building permit from the City of Canning has to be in hand before construction starts.

The pack is a site plan, elevations, structural engineering matched to the assessed wind classification, and a stormwater design suited to the soil on your block. Class 10a work can be lodged uncertified for the council to assess, or certified with a certificate of design compliance already attached.

Development approval is the separate question and the R-Codes govern it. Boundary setbacks, remaining open space and whether the required outdoor living area stays uncovered are the usual triggers, and on the older large lots the answer is generally straightforward.