Structural · 7 min read
Single storey house structural design in Brisbane: what you get and what it costs
A single storey house looks simple until you price the footings on reactive clay or work out the wind bracing for an open living area. This is what structural design covers for a new single storey home in Brisbane and South East Queensland, what your builder and certifier will ask for, and what our fee includes.
What a single storey structural design includes
We design the parts of the house that carry load and resist wind, then issue drawings and calculations a private certifier will accept.
- Footing and slab design to AS 2870 based on the site classification (M, H1, H2 and so on)
- Wall framing, lintels and beams over openings — timber to AS 1684 or steel to AS 4100
- Roof framing, trusses, rafters and hip and valley beams
- Wind bracing and tie-down for the region C or B wind classification
- Steel posts, portal frames and transfer beams for large openings and alfresco spans
- Retaining or cut and fill details where the slab sits on a sloping block
Reactive clay is the biggest cost driver
Much of Brisbane sits on reactive clay that swells and shrinks with moisture. A site classified H1 or H2 needs a stiffer raft, deeper beams or piers, and that changes the concrete and steel quantities well before the builder starts.
A geotechnical report is worth its cost. Without one, an engineer must assume a conservative classification, and you pay for that assumption in the slab.
Sloping blocks and split levels
On a sloping block the choice is usually between cut and fill with a retaining wall, a stepped slab, or a suspended floor on piers. Each has a very different cost, and the cheapest structure is not always the cheapest build once earthworks and walls are counted.
We look at all three and tell you which one suits your site, then design the one you choose.
What it costs and what you need to send
Single storey structural design starts at $1,200, including calculations, drawings and RPEQ certification. Send architectural plans, the survey plan and a geotechnical report if you have one, and you get a fixed fee back.
The quote is free, and the price does not move once it is accepted unless the architecture changes.
Frequently asked questions
- How much does structural design cost for a single storey house in Brisbane?
- From $1,200 for a standard single storey home, covering footing and slab design, framing, bracing, tie-down, drawings and RPEQ certification. Larger or unusual homes are quoted on the plans.
- Do I need a soil test before structural design?
- It is strongly recommended. A geotechnical report gives the site classification for AS 2870 and usually saves more in concrete and steel than the test costs.
- How long does it take?
- Typically five to ten working days for a single storey home once we have complete architectural plans.
Send your plans for a fixed single storey design fee from $1,200.
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