Want a wall gone, worried about a crack near the soakwell, or need a patio certificate for the City of Joondalup or City of Wanneroo? Call now and we'll pass your enquiry to an independent structural engineer who quotes the job.
Joondalup and Wanneroo cover a big slice of Perth's northern corridor, and Wanneroo is still growing fast. The ABS put it at 246,147 residents in June 2025, up 7,531 in a year, with Joondalup at 176,595. The structural questions owners here ask tend to be practical ones: is this wall load-bearing, why has a crack opened above the laundry door, and what does the council want before it issues a permit for the new patio?
Kings Park Structural Co is advertising, not an engineering firm. We pass your enquiry to an independent structural engineering firm, which quotes you and contracts with you directly, and that firm pays us for the introduction. Sometimes the most useful first step is finding out whether you need an engineer at all, so start with the cost guide or call now on (08) 5550 6237.
About 68% of WA's detached houses are brick, the only state above half, and in double-brick homes some internal walls usually hold up ceilings and roof. The engineer works out what your wall carries and designs the beam, posts and footings your builder needs for the permit.
On sandy ground, a leaking pipe or a soakwell dug too close to the house can wash sand out from under a footing. An engineer's report looks at walls, slab and footings, records the cracking or movement and says what it points to.
A roofed patio or alfresco cover doesn't fit WA's pergola exemption, so check with the City of Joondalup or City of Wanneroo before you build. The engineer's certificate states the site class, design wind speed and the drawings it covers.
Adding floor area or height takes the work outside the permit exemption, so the building surveyor will want structural drawings. Footing design depends on the AS 2870 site class of your block.
Geoscience Australia describes Bassendean Sand across much of the central Perth region, with Tamala Limestone and the Spearwood and Quindalup dune sands along the coastal strip. A Perth geotechnical firm says sand is the most common soil in the metro area and is normally Class A under AS 2870, meaning little movement from wetting and drying. Soft or loose sand sites are Class P, though, and nobody publishes soil maps suburb by suburb. The engineer judges your block, not your postcode.
Sand doesn't swell and shrink like clay, but CSIRO notes it is particularly easy to wash away. A leaking water, sewer or stormwater pipe, a downpipe that isn't connected, or reticulation left running too long can all move sand from under a footing. In brickwork that usually shows up as step cracking along the mortar or vertical cracks at windows and doors.
The City of Joondalup requires a soakwell to sit at least its own width away from buildings and boundaries (where the width is equal to or greater than the depth), so digging it doesn't undermine footings, fences or walls. We haven't found a published equivalent for the City of Wanneroo, so ask the council. If a crack has opened near a new soakwell, a burst pipe or a freshly watered garden bed, mention it when you ring. CSIRO says most masonry cracking is only a cosmetic nuisance, but it also says monitoring a crack should always be treated seriously, and only someone who has seen the wall can tell you which kind you have.
For houses, the City of Joondalup and the City of Wanneroo are the permit authorities. Under the Building Regulations 2012 a pergola is exempt from a permit only if it has no roof, stands no higher than 2.4 metres, covers no more than 20 square metres and isn't in wind region C or D. A roofed patio isn't a pergola under that rule, and a stand-alone shed is exempt only up to 10 square metres and 2.4 metres high.
When a permit is needed, you may be asked for a structural engineer's certificate, often called a certificate of structural adequacy or structural sufficiency. That name isn't a statutory form in WA. What matters is that the certificate states the AS 2870 site class, the design wind speed and the documents it covers. Certified applications carry a 10 business day decision period and uncertified ones 25 business days, and the permit fee is 0.19% (certified) or 0.32% (uncertified) of the estimated value of the work, with a $121.00 minimum.
Some Perth firms sell standard steel patio drawings online that aren't designed for a particular site. One advertises them at A$330 (GST not stated). Whether your council will accept a standard detail for your block is worth asking before you pay for anything, and the patio and shed certificates page covers the difference.
None of the Perth engineering firms we checked publishes a fixed fee for a crack report, beam design or a site-specific patio certificate. Engineers quote each job, and the price depends on the house, the structure and what the council needs. Send photos, plans or a short description and the engineer who quotes your job will tell you what they need to see. The Perth cost guide explains what is and isn't published.
Registration of structural building engineers in WA began on 1 July 2024, with a transition period running to 1 July 2027. From that date structural engineering work must be done by a registered building engineer, and you can look up any engineer on the DEMIRS Building and Energy register before you sign. The engineer assesses and designs. A registered builder does the building work, whether that's the beam, the patio or any repair.
If an insurer is involved, many home policies exclude gradual subsidence and ground movement, and some exclude leaks that went on for a long time when the owner should have known about them. Read your own policy's exclusions before you assume a crack is or isn't covered. Looking elsewhere in Perth? See Cockburn, Melville and Canning or the western suburbs and Fremantle.
Often, yes. A roofed patio or alfresco cover isn't a pergola under WA's permit exemption, which only covers roofless pergolas up to 2.4 metres high and 20 square metres outside wind regions C and D. If the council or building surveyor asks for engineering, the engineer's certificate states the site class, design wind speed and the drawings it covers. Check with the City of Joondalup or City of Wanneroo before you order materials.
A lot of Perth sand is Class A under AS 2870, which means little movement from moisture changes. The risk on sand is erosion: water from a leaking pipe, a disconnected downpipe, heavy reticulation or a soakwell too close to the house can wash sand from under a footing. Soft or loose sand sites are Class P, and there's no published soil map for individual suburbs. An engineer can only judge your crack after seeing it.
The Building Regulations 2012 set 10 business days for a certified application and 25 business days for an uncertified one, unless you agree in writing to longer. The clock stops if the council asks for more information, so a complete application with the engineering attached helps. The permit fee is 0.19% (certified) or 0.32% (uncertified) of the estimated value, with a $121.00 minimum.
Removing or altering anything that supports another part of the house isn't exempt building work in WA, so it needs a permit. In double-brick homes some internal walls usually carry ceilings and roof, which is why a quick look isn't always enough. The engineer who quotes your job can tell you whether the wall needs a beam design or whether engineering isn't required at all.
Tell us what you need looked at and get a written quote.
