The submissions are made by a Qualified Person you appoint. An interior designer cannot make them, and the paperwork drives the programme.
The single most useful thing to understand early is that this is a building project, and the consultant appointments come before the design is finalised.
The approval route, in order
For additions and alterations you appoint a Qualified Person — a registered architect or professional engineer — who first obtains written planning permission from URA, then submits building plans to the Commissioner of Building Control at BCA. A permit is required for all building works except those classified as insignificant building works, and BCA issues that permit after building plan approval. If you are retaining existing structures that do not meet current guidelines, a Professional Engineer must certify that they are structurally sound and will not be damaged by the new works. None of these submissions can be made by an interior designer, and the sequence cannot be reordered to save time.
URA's A&A limits shape the design before you draw it
There are real caps on what counts as additions and alterations rather than a rebuild. Broadly, added gross floor area, replaced external walls and structural changes to the existing floor area must each stay within 50% of what is existing and approved. Cross those thresholds and you are into a different and considerably longer approval process. Testing a concept against those limits at the start is much cheaper than discovering it at submission, and conservation properties have a separate submission route again.
The building fabric is the biggest unknown
Unlike a flat, you own the roof, the facade, the external drainage and the boundary. Roof condition, flashing details, external wall and render failure, timber rot in older properties, and drainage that no longer falls correctly are all common and none of them are visible from a floor plan. A condition survey before design is not an optional extra on a landed project — it is what makes the eventual cost figure mean anything.
Services are a design decision, not a fitting-out one
Electrical capacity, the position of the distribution board, air-conditioning strategy across multiple storeys, hot water provision, and drainage falls all have to be resolved while the layout is still on paper, because they drive ceiling voids, riser positions and floor build-ups. Retrofitting them afterwards means opening finished work. On a house, coordination between the interior design and the engineering scope is where projects are won or lost.
Programme and cash flow are longer than people expect
Approvals alone can take months before anyone is on site, and site works on a substantial A&A commonly run many months more. We would rather set that expectation at the first conversation than present an attractive programme that cannot survive the submission process. It also matters for where you will live in the meantime, which is a real cost that rarely appears in a renovation budget.
Approvals & rules
Who approves the work.
Approving bodyURA and BCA, via a Qualified Person you appoint
Appoint a Qualified Person — a registered architect or professional engineer — to act on your behalf.
Written planning permission from URA must be obtained before applying for building plan approval.
Building plans are submitted to the Commissioner of Building Control at BCA.
A permit is required for all building works except insignificant building works, issued after plan approval.
Retained non-compliant structures require Professional Engineer certification that they are sound.
Added floor area, replaced external walls and structural changes must each generally stay within 50% of the existing approved extent.
Conservation properties follow a separate URA submission process.
Rules and timeframes change. These were checked against the linked official pages on the date shown — please confirm anything critical with the relevant authority.
What drives the cost
Where the money actually goes.
Listed roughly largest first, for this property type specifically. A reliable figure still needs a site assessment — this is what to expect it to be made of.
We do not quote a fixed package price, because two homes of the same size rarely need the same works.
01
Extent of structural alteration, which drives both consultant scope and build cost
02
Condition of the building fabric — roof, facade, external drainage, timber
03
Mechanical and electrical scope across multiple storeys
04
Consultant and submission fees, which are a real line item on a landed project
Interior finishes and carpentry, at the specification level a house tends to attract
Common mistakes on this property type
Finalising a design before a Qualified Person has tested it against URA's A&A limits
Treating a landed project as an interior job and appointing consultants late
Skipping the condition survey and carrying the building fabric as a surprise
Ignoring the 50% thresholds until submission
Not budgeting for alternative accommodation during the works
How long it takes
Timeline, honestly.
Approvals commonly take several months before site start, with site works on a substantial A&A running many months more. Any programme given before the consultant appointments is an estimate, not a commitment.
Delays most often come from late material selections or changes requested mid-build, not from the site work itself.
Questions worth asking
What we'll ask you first.
01
Is this a refresh, a reconfiguration, or an extension?
02
Has a Qualified Person been appointed, or do you need a recommendation?
03
What is the condition of the roof, facade and external drainage?
04
Is the property in a conservation area?
05
Where will the household live during the works?
Not sure of the answers yet? That is fine — working them out is part of the first conversation. For the wider picture, the renovation guide covers permits, hours, materials and costs in detail.
Start with clarity
Ready to talk through your landed house renovation?
Tell us your property type, timeline and the work you have in mind. We'll help you decide the next practical step.
