Most of the homes we are asked about in Perth are already standing. Renovating, extending or right-sizing an existing house is usually the better move — financially, environmentally and in terms of what you end up with — but it is a different exercise from building new, and it rewards different decisions.

This guide covers what matters when you renovate, extend or downsize a Perth home, in the order those decisions actually get made.

Renovate, extend or rebuild?

This is the first question, and it is worth answering properly before you start drawing.

Renovating keeps the structure you already own. You are reworking internal layouts, kitchens, bathrooms, services and finishes — and you avoid the cost, time and embodied carbon of new walls and a new roof.

Extending adds floor area: a rear addition, a new wing, an upper level, an enclosed verandah or a separate studio. It usually means the existing house needs some work too, especially where the new meets the old.

Right-sizing is the quieter option. Many households only need their existing home rearranged and made more efficient, not enlarged. Less floor area means less to heat, cool, clean and maintain.

Rebuilding is worth considering when the existing structure is failing, the layout can never suit, or the house sits badly on the block.

The honest answer often comes from looking at the existing building carefully: what is sound, what is salvageable, and what the site allows.

What we look at first on an existing Perth home

Structure and condition. Footings, timber frames, roof structure and the state of walls and floors set the limits of what is sensible. A structural review early avoids designing something the house cannot carry.

Orientation and light. Older Perth homes often have their living areas facing the wrong way, or windows that catch the full western sun. Rear additions are an opportunity to turn the plan towards the north and fix what the original house got wrong.

The original roof and ceiling. Removing a ceiling or roofline changes how an addition feels, and how the two parts of the house connect. It is often what makes an extension read as part of the house rather than a bolt-on.

Services. Electrical, plumbing, and the position of kitchens and bathrooms limit how freely you can rearrange. Moving services costs more than moving walls.

What the streetscape and the council care about. Setbacks, site cover, overshadowing, privacy, and in many areas, the character and heritage value of the existing house.

Extending an existing home

Extensions in Perth tend to fall into a few shapes:

• Rear additions that open living areas onto gardens or courtyards, bringing in northern light and better airflow.
• Upper-level additions that gain space without losing garden, and where outlook and privacy can be improved — structurally the most demanding option.
• Side additions and infill where a wide or corner block allows a new wing.
• Detached or attached studios, sleepouts and ancillary spaces for work, guests, teenagers or hobbies.

Whichever shape suits your block, the same principles govern how comfortable it ends up: sun kept out in summer, warmth let in during winter, and air able to move through the combined plan.

Small and affordable homes

A smaller home is not a lesser home. It is a decision about where money goes.

• Spend on the fabric. Insulation, glazing, shading, draught sealing and efficient services deliver comfort and lower bills for the life of the house. Feature materials can come later.
• Compare area to amenity. A well-planned 100 square metres can live better than 150 laid out carelessly. Alcoves, built-in storage and dual-purpose rooms earn their space; corridors and oversized entries do not.
• Design for the block you have. Narrow lots, sloping sites, battle-axe blocks and small infill lots all have workable answers, and they usually beat a compromised larger design.
• Plan for what is coming. Solar, batteries, EV charging, ageing in place, or a future studio. Preparing for those now costs little; retrofitting them can be disruptive.
• Keep the existing structure where you can. Retaining sound walls and roofs is usually the largest single saving, and it cuts the carbon tied up in new materials.

Planning, approvals and building — what we handle

Every project we take on involves some combination of:

• Site and existing-building assessment, including structural and heritage considerations.
• Design development, with thermal performance considered during design rather than documented at the end.
• Planning approval through the relevant local government or the state planning framework, where it is required.
• Building approval documentation, including the energy and construction compliance your project needs.
• Tender and construction support, so the work is built to the drawings and decisions are made with someone in your corner.

Perth metro projects bring infill, narrow lots, subdivided blocks and established streetscapes. Regional Western Australian projects add distance and trade logistics, bushfire considerations, water and power constraints, and often heritage or civic context. We work in both and design for what is actually in front of us.

Choosing an architect for a renovation

Look for someone who has read the existing building, not just measured it — who can tell you which parts of your house are worth keeping and why. Ask how they will handle the join between old and new, how your energy performance will be improved rather than just assessed, and who is responsible for approvals and for coordinating the builder.

Office of Regional Architecture is an accredited architectural practice. Our head office is now in Perth, and we design renovations, extensions and smaller homes across the Perth metro area, while continuing to work with clients throughout regional Western Australia. Our practice covers residential, community, commercial, heritage and landscape projects, with sustainability built into all of it — lower carbon, lower resource use, and better outcomes for each site.

The most useful first conversation happens before you commit to a direction. If you are weighing up renovating, extending or simply rearranging what you already have, talk to us early.