Is it better to retrofit or build new for SDA?

The retrofit question comes up on almost every site with an existing dwelling on it, and the honest answer varies enormously by design category.

The mistake is treating it as one question. It is four different questions, one per category, with four different answers.

What a retrofit can usually achieve

Improved Liveability is the category most often reachable in an existing dwelling.

Its provisions are heavily weighted toward things that can be changed: lighting, contrast between surfaces, the way spaces read for someone with sensory or cognitive impairment, door hardware, and a level of accessibility that a well-built existing house may already be partway toward.

Where a house has a reasonable footprint, a workable entry and adequate room sizes, the gap is often closeable.

What a retrofit usually cannot achieve

Fully Accessible and High Physical Support fail on the things that were decided when the building was set out.

Circulation space is the first. Turning circles and clearances required for a wheelchair user are dimensions, and dimensions in an existing house are fixed by walls that are frequently structural.

Level access is the second. A dwelling with a step at the entry, a change in floor level, or a bathroom that was built up to fall to a waste is not easily brought to a flush threshold. On a sloping site it can be effectively impossible.

Structural provision for a ceiling hoist is the third. High Physical Support anticipates assistive technology, and a ceiling that was never designed to carry it has to be rebuilt rather than reinforced.

Bathrooms are where most retrofits die. An accessible bathroom is not a bathroom with a grab rail. It is a room of a certain size, with a certain layout, drained and waterproofed a certain way, and the existing one is almost never it.

Robust

This category is its own case. It anticipates a resilient fabric, considered sightlines, and durability well beyond ordinary residential construction.

That is not achievable by upgrading finishes. It is a specification that runs through the structure, the linings, the fixtures and the glazing, and applying it to an existing building generally means rebuilding most of what is behind the surface.

The cost pattern

A retrofit begins cheaper and converges. Every element that has to be structurally altered brings the cost closer to a new build, and the point where they meet arrives faster than people expect.

The other cost is certainty. A new build is documented, certified against the design, and constructed to that certification. A retrofit is a series of discoveries, and each discovery is a variation.

For a lender or an investor, that variance is worse than the number itself.

What decides it

The design category being targeted, which should be driven by participant need rather than by what the existing building allows.

The structure. Whether walls can move, whether the floor can be levelled, whether the ceiling can carry.

The entry and the site. Level access is the single most common blocker, and it is set by the ground.

The evidence path. A retrofit still has to be certified against the standard by an accredited assessor, and work concealed behind existing fabric is harder to evidence.

The question to ask first

Not "can this house be made compliant." Ask "which category do the intended residents need, and can this structure support it."

If the answer is a category the structure cannot reach, the retrofit is not cheaper. It is a project that produces a dwelling that cannot be enrolled as what it needs to be.

Our co-founder is an ACAA Accredited Access Consultant and an NDIS Accredited SDA Assessor, and that assessment is the right first step on any existing building.

Discuss your project and we will assess what the structure can actually support.

MADEmodular / MADEbetter.