An alterations and additions architect in Sydney does one thing a new-build designer does not: works with a house that already exists. The existing structure, the planning controls on the lot and the way the family lives all constrain the answer.
An alterations and additions architect in Sydney does one thing a new-build designer does not: works with a house that already exists. The existing structure, the planning controls on the lot and the way the family lives all constrain the answer. A renovation that gets approved and builds on budget comes from handling those in the right order. This is that order.
Start with the house you have
Before any design, the existing building has to be understood. That means a measured survey of the house and a detail survey of the site, so the drawings reflect what is there instead of what an old plan says.
It also means looking at how the house was built. Sydney's housing stock has patterns. Federation and interwar houses in the Inner West and lower North Shore often have solid brick walls, high ceilings and a run of small rooms at the back. Post-war homes may be brick veneer or fibro on timber frames. Each takes change differently.
The most useful early question is which parts are worth keeping. Front rooms with good proportions usually are. Later lean-to additions at the rear usually are not.
Check what the planning controls allow
Three numbers and a handful of overlays decide how much you can add:
- Floor space ratio, where your council applies one.
- Building height.
- Setbacks from side and rear boundaries.
- Landscaped area, which limits how far out you can build.
- Heritage, bushfire, flood and tree controls.
A Section 10.7 planning certificate from council lists the overlays. Your council's development control plan sets the detailed rules. Both should be read before a line is drawn, and both are available through council or the NSW Planning Portal.
Heritage conservation areas change the approach
Large parts of the Inner West, Eastern Suburbs, lower North Shore and Ku-ring-gai sit in heritage conservation areas. In those areas the fast-track complying development pathway is generally unavailable for external work, and a development application is required.
Council will expect the street presentation to be kept. Additions go to the rear, sit below the main ridge, and use materials that respect the original without imitating it. A heritage impact statement usually accompanies the application.
This is not a reason to avoid renovating. Most of the alterations and additions we have designed are in established suburbs of this kind. It does mean the design has to be argued, and that is where experience shows.
Decide between out, up or reconfigure
There are three ways to get a better house from the one you have:
- Reconfigure. Move walls, relocate the kitchen and bathrooms, open the back to the garden. No extra floor area, often the best value.
- Extend out. A ground floor rear addition. The simplest structure, at the cost of yard.
- Extend up. A second storey or an attic conversion. Keeps the garden, involves the most work to the existing house.
Many projects combine two. The right mix depends on the lot, the controls and the budget.
Our honest advice: test the reconfigure option first. Plenty of families who come in asking for an extension need a better plan, not a bigger house. Extra floor area that does not fix a poor layout is money spent on the wrong problem.
Design around how you will live and how it will be built
Good alterations and additions resolve the join between old and new. Floor levels, ceiling heights and roof lines rarely line up without thought. The junction is either made seamless or made deliberate, and both are legitimate.
Buildability matters as much as appearance. The design should account for:
- how builders get materials to the rear of a house with narrow side access
- what can be demolished without propping the rest
- whether you can stay in the house while work proceeds
- where new plumbing connects to old drainage
- the order of work, so the house is weathertight as early as possible
These are questions of sequencing and structure, and they belong in the design stage. Our additions and alterations work is documented with construction staging in mind for that reason.
Get the approval pathway right
Where the site allows it and the design meets every standard, a complying development certificate is the quicker route. Otherwise a development application goes to council. Alterations costing $50,000 or more also need a BASIX certificate covering energy and water performance.
Settle the pathway early, because it shapes the drawings. Our DA and CDC documentation page explains the difference.
Budget honestly
Renovating costs more per square metre than building new. Work is done around an existing structure, access is harder, and old houses hide things: undersized footings, asbestos sheeting, wiring that has to be replaced once it is disturbed.
We do not quote build prices, and you should be wary of any figure given before a design exists. What we recommend:
- hold a contingency for unknowns in the existing house
- arrange an asbestos inspection for any home built before the 1990s
- have a structural engineer look at the house before the design is fixed
- get builders to price a complete set of construction drawings, not a sketch
NSW guidance on asbestos in homes is published by SafeWork NSW.
What to prepare before the first meeting
- a list of what does not work in the house now
- rooms and spaces you need, ranked
- photos of every room and the yard
- any old plans, and the survey from your purchase if you have it
- the Section 10.7 certificate
- an honest total budget, including fees and contingency
Next step
Send us the address, a few photos and your list of what is not working. We will come back with what the controls allow and which of the three approaches suits the house.
Common questions
What does an alterations and additions architect do?
An alterations and additions architect designs changes to an existing house, prepares the approval documents and produces construction drawings for builders to price. The work includes measuring the existing building, testing planning controls, resolving how new work joins old, and coordinating the engineer and other consultants.
Do I need a DA for alterations and additions in Sydney?
It depends on the site and the design. Work that meets every State complying development standard can be approved with a complying development certificate. Properties in heritage conservation areas, or designs that vary a control, generally need a development application to council.
Is it cheaper to extend or to rebuild?
It depends on how much of the house is being kept. Modest additions to a sound house usually cost less than rebuilding. When most of the structure is being altered, a rebuild can cost a similar amount. Heritage controls may rule out demolition regardless.
Can I live in the house during a renovation?
Sometimes. Rear additions can often be built while the family lives in the front of the house. Second storey additions and full internal renovations usually require moving out for part of the build. The design and staging decide what is practical.
How long does it take to get a renovation approved?
A complying development certificate is commonly issued within weeks of a complete application. A development application commonly takes several months. Survey, design and documentation come first and add to the overall timeframe.