Structural Renovations near you

Volume Two sets out the structural deemed-to-satisfy clauses at H1D2 to H1D11. H1D2 points to Section 2 of the ABCB Housing Provisions or to the specific clauses following. H1D3 covers site preparation, referencing Part 3.2 for earthworks, AS 4678 for earth retaining structures and Part 3.4 for termite management. H1D4 covers footings and slabs through AS 2870, AS 3600 and Section 4 of the Housing Provisions. H1D5 covers masonry through AS 3700 and AS 4773.1 and AS 4773.2.

Framing is H1D6, and it is the clause most structural renovations live in. It references the NASH Standard for residential and low-rise steel framing, AS 4100 for steel structures, AS/NZS 4600 for cold-formed steel, AS 1720.1 and AS 1720.5 for timber design, the AS 1684 residential timber framing series and AS 1860.2 for particleboard flooring. H1D9 deals with earthquake areas through Section 2 of the Housing Provisions.

A design that sits inside those standards can be documented and approved as a deemed-to-satisfy solution. A design that does not, which includes most long-span openings and most retrofitted steel in a house, is a performance solution assessed against H1P1. Neither is better or worse; they cost different amounts of time and documentation, and knowing which one you are buying is the point.

The permanent structure is designed, documented and inspected. The temporary condition, the hours or days when the old wall is gone and the new beam is not yet loaded, is where structural renovations injure people, and it is the part most often left to on-site judgement. Propping has to pick up the load before the wall is disturbed, it has to bear on something capable of taking it rather than on a floor that is itself spanning, and it has to stay in place until the permanent member is bearing properly.

This is not homeowner work, and it is not work to supervise from the next room. Have the engineer specify the temporary support as part of the design, not as an afterthought, and keep the house's occupants out of the affected area while it is in place. Demolition of a loadbearing element is also frequently the point at which older materials are disturbed, so establish what the wall is made of before anyone starts cutting.

The same caution applies to excavation near a boundary or near a neighbour's footing. Performance requirement H1P1 expressly contemplates the protection of adjacent properties, and a dispute with a neighbour about a cracked wall is far cheaper to prevent with a pre-works condition survey than to resolve afterwards.

The usual cause is not the beam. It is what the beam lands on. A wall spreads its load along its length; a beam concentrates the same load at two bearing points, and those points need piers, pads or new footings capable of accepting them. When an existing footing turns out to be shallow, undersized or sitting on reactive clay, the scope grows underground where nobody can see it and nobody budgeted for it.

Reactive soils deserve particular mention in Australia, because AS 2870 exists precisely because so much of the country's residential building sits on clay that moves with moisture. A structural alteration that changes drainage, removes a tree or alters how water reaches the soil next to a footing can set off movement that has nothing to do with the beam you installed.

The other common surprise is the ceiling and roof above. Once a wall is out, any sag that the wall was quietly holding up becomes visible, and levels that were never quite right become obvious across a newly open space. Agreeing in advance what will be corrected and what will be accepted saves an awkward conversation at the plastering stage.

Structural work is the category where documentation has the longest useful life. Keep the engineer's drawings and computations, the certification that the work was carried out in accordance with the design, the building approval, the inspection records, and photographs of the bearings and connections before they were covered. A buyer's building inspector will ask, an insurer may ask after any future damage, and a subsequent renovation will be far cheaper to design if the next engineer can see what is there.

Licensing and residential building insurance requirements sit on top and are set state by state, with their own thresholds and prescribed contract terms. Confirm that the contractor's licence class genuinely covers structural work rather than assuming a general licence does, and check it on the regulator's public register for your state rather than accepting a card or a number on a quote.