Home Extensions and Second Storey Additions

The first question is whether the block can take the extension. Site cover limits, setbacks and the yard you actually use put a ceiling on how far a ground-floor extension can spread, and on a smaller lot a rear extension can consume the last of the outdoor space. Going up preserves the yard and often captures outlook and breeze, but it costs more per square metre and asks a great deal more of the existing structure.

A second storey needs the existing frame, walls and footings to carry it. Post-war timber homes on stumps, and brick veneer or double brick homes on strip footings, were designed for one level. Sometimes the structure can be strengthened; sometimes the practical answer is a new steel or engineered timber frame that stands inside or beside the existing walls and carries the upper floor independently, down to new footings.

The honest comparison covers cost, time, disruption and result. Where a ground-floor extension delivers the rooms you need without ruining the yard, it usually wins. Where the block is tight or the outlook is up, a second storey earns its cost. We put both in front of you rather than assuming.

Before design goes far, a structural engineer assesses what is there: slab or stumps, footing depth and condition, wall framing and bracing, lintels and the roof structure. On a raised home that means getting under the house; on a slab home it may mean a small excavation at a footing to confirm its depth. For a second storey this is not optional.

Floor levels and roof tie-ins are where additions show their quality. A new floor has to meet the old one without a step, and the new roof has to connect to the existing roof so water is shed rather than trapped at the junction. Box gutters at tie-ins are a common failure point and are designed out wherever possible.

A new stair reshapes the ground floor. It needs roughly the footprint of a small bedroom, has to land somewhere sensible on both levels, and has to comply with current rise, going and headroom requirements. Its position is often the single decision that determines whether the rest of the ground floor plan works.

Services move with the structure. Plumbing stacks for upstairs bathrooms need to drop through the ground floor in places that suit both levels, and an older switchboard commonly needs upgrading once the load and the circuit count increase.

Every extension and addition needs building approval through a private certifier. Development approval from council is triggered when the work departs from the accepted standards — exceeding a height limit, encroaching on setbacks, sitting on a small lot, or falling within a character or neighbourhood overlay. Whether a given addition triggers it varies by council and by lot, so we check the current council requirements before committing to a design.

Inside a character overlay, particularly on pre-1947 homes in inner Brisbane, a second storey is usually assessed for its effect on the streetscape. A design that sits behind the existing roofline or reads as a subordinate form generally has an easier path than one that changes the front elevation.

Then there is the question of whether the new work should match or contrast. Matching brick after decades of weathering is difficult, and a deliberate contrast in cladding — lightweight sheet or timber over the existing brick, for example — is often more convincing than a near miss. Either approach works if it is decided rather than defaulted into.

Staying in the house through a ground-floor extension is often workable behind a sealed hoarding between old and new. Staying through a second storey addition is much harder: the roof comes off, ceilings are exposed and services are interrupted. We stage the work so the existing roof is removed in sections with temporary roofing in place before each section goes, but for most families a period out of the house is the realistic option and we say so early.

Before any demolition, we check for asbestos and termites. Asbestos is likely in eaves, wet area linings and some flooring in homes built before the late 1980s, and it requires licensed removal with documentation. Termite damage in timber framing is common across SEQ and can change what the structure is able to carry.

Hidden conditions on additions are predictable in kind if not in extent: undersized or decayed footings, non-compliant previous work, rotted top plates, undersized lintels, and wiring or plumbing that has to be replaced once exposed. We investigate before contract, then price on a fixed basis with a clearly stated contingency for what remains hidden. Anything we find is reported and priced in writing before we act on it.