Flat Patios Joondalup

Two broad vintages cover most of the City of Joondalup. Duncraig, Padbury, Sorrento, Craigie and Kallaroo went up largely in the 1970s and early 80s on blocks around 700 square metres. Currambine, Kinross, Iluka, Connolly and Burns Beach came later and smaller, often on 400 to 550 square metres.

The older group gives you room. There is generally enough depth behind the house to run a patio four or five metres out and still keep lawn, and the single-storey rooflines are low enough that a flat roof tucks under the existing gutter without argument.

The newer group is tighter and frequently two storey. Here the patio is squeezed between the rear wall and a fence that is closer than it used to be, and the fixing point is often an upper-floor wall rather than a fascia. Both are workable, they just need different detailing at the house end.

Perth sits in wind region A, which is the non-cyclonic classification. Within that, an individual site gets a rating under AS 4055 based on terrain, shielding and topography, and in ordinary suburban Perth that usually lands at N2.

Closer to the water it climbs. A rear yard in Burns Beach or Ocean Reef, with open ground or dune between it and the sea, has very little upwind shielding, and N3 becomes the sensible starting assumption rather than the exception.

The rating is not a formality. It drives post size, footing depth and diameter, purlin centres, and the number and type of fixings holding the sheets down. An engineer sets those numbers against the rating for your address, and the certificate that comes back is what the council reads.

Salt does not need to be visible to be working on your steel. Onshore wind carries it inland every afternoon through summer, and the closer you are to breaking surf the harder the marine environment sits on ordinary coated steel and standard fasteners.

For the suburbs along the water the spec shifts. Marine-grade Colorbond rather than the standard product, stainless fasteners rather than plated ones, and a hard look at any dissimilar metals in contact, because that is where the first bubbling usually shows.

Inland Joondalup is different again. Woodvale, Greenwood, Warwick and Edgewater sit far enough back that standard grades behave normally, and paying for marine steel there buys nothing you can point to.

Joondalup ground is Spearwood dune sand over limestone, and both parts of that matter. Loose sand gives a post almost no lateral resistance, so the footing has to be deep and wide enough that the mass of concrete does the work the soil will not.

Then there is the limestone. Auger down in Sorrento, Marmion or parts of Hillarys and you can hit hard cap at half a metre. That is not a problem, it is a change of tool and sometimes a change of footing design, and it is much cheaper to discover at quote stage than on install day.

The upside of sand is drainage. Soakwells in this ground clear a downpour fast, and you rarely need the oversized array that river-flat suburbs on the other side of town require.

Every square metre of new roof you add has to dispose of its own water on your own land. That means soakwells, sized against the catchment area of the patio roof and the storm event the council nominates, connected by downpipe and stormwater line.

Joondalup sand makes this straightforward. The wells empty between storms, so they are ready for the next one, and they can usually sit clear of the house without a long run of pipe across the yard.

What still catches people out is the neighbour boundary. Water off your patio cannot be shed onto the block next door, and a flat roof with a fall running the wrong way is the quickest way to create that problem.

A patio is a Class 10a structure under the National Construction Code, and in Western Australia it needs a building permit before work starts. For Class 10a you can lodge an uncertified application that the City of Joondalup assesses, or a certified one carrying a certificate of design compliance from a registered building surveyor.

Either way the council wants a site plan, elevations, the structural details and engineering for your wind classification, and the stormwater design. Missing engineering is the single most common reason a patio application sits waiting.

Planning approval is a separate question and it only comes up when the design steps outside the deemed-to-comply provisions of the R-Codes. Boundary setbacks, open space and the outdoor living area are the usual triggers on the smaller Currambine and Iluka lots.