How to Choose a Builder for a Home Extension in Sydney

An extension is harder than a new build in one important way: you are cutting into a house that already exists, that someone lives in, and that will not always match its drawings. The builder you choose matters more because of it.

Start with the right shortlist

Look for builders who regularly do extensions on homes of a similar age and type to yours. A builder who mostly works on new project homes is not automatically the right fit for cutting a first floor onto a 1930s brick cottage.

Ask each candidate:

• What proportion of your work is extensions and renovations?
• Have you worked on homes like this one, and in this part of Sydney?
• Who actually performs the structural work, and who is subcontracted?
• Who runs the site day to day, and how often are they on it?
• How many jobs will you be running at the same time as mine?

A builder with carpenters in house, as ORT Constructions has through our carpentry team, controls more of the critical path than one who subcontracts the framing.

Verify the basics

• Current licence for residential building work of the value involved
• Public liability insurance and home building compensation cover where required
• Workers compensation if they have employees
• The name on the licence matching the name on the contract

Check the licence yourself through the NSW licence check service rather than accepting a number on a quote.

Compare quotes properly

Never compare two quotes with different scopes. Give every builder the same written scope, then look for:

• Line items rather than one lump sum
• Named products where selections are known
• Clear exclusions
• Whether demolition, waste, scaffolding, site protection and final clean are included
• Whether excavation is priced with a rock allowance
• Whether structural steel and engineering are included
• What happens to unspent allowances

The most detailed quote is often not the cheapest, but it is usually the most accurate.

What to look for on their previous work

• Photos of the same type of work, not just finished kitchens
• Where new work joins old: roof junctions, floor levels, wall lines
• Whether the site in the photos looks organised
• Whether they can put you in touch with recent clients
• Whether they will show you a job in progress

A tidy site is not a cosmetic point. It correlates strongly with how the rest of the job is run.

Red flags

• Pressure to sign quickly, or a discount that expires
• Large deposits well beyond what the work justifies
• Reluctance to provide a written scope or contract
• Cash arrangements, or vague answers about licensing and insurance
• A quote noticeably cheaper than every other with no explanation
• No process for handling variations

Questions that separate good builders from average ones

• What do you expect to find once we open this house up?
• What in this design will be difficult to build, and why?
• How will you protect the parts of the house we are still living in?
• How do you sequence the work so we keep a kitchen or bathroom as long as possible?
• What are the long lead items, and when do they need ordering?

Good builders answer these specifically. They have seen the problems before.

Then read the contract carefully

Questions to ask a builder before signing a building contract goes through payment schedules, variations, delays and defects. For a broader view of assessing any trade business, how to choose a reliable tradie or builder in Sydney is worth reading too.

Check how they handle the existing house

This is the difference between an extension builder and a new home builder. Ask specifically:

• How will you protect the parts of the house we are living in from dust and weather?
• How do you handle the roof junction between the new work and the old?
• What do you do when a wall turns out to be load bearing and the drawings said otherwise?
• Who fixes the existing floor if it is out of level, and how is that priced?
• How do you match existing skirtings, architraves and cornices?

Those answers tell you whether they have thought about the interface between new and old, which is where extensions are judged once they are finished.

References worth calling

Ask for two or three clients from the last year or two, and when you call, ask questions that invite honesty:

• What surprised you about the process?
• How were variations handled?
• Did the program hold, and how were you told when it did not?
• Was the site left tidy each day?
• Would you use them again, and would you change anything?

A builder with nothing to hide will hand over contacts without hesitation.

Look at how the quote is presented

The quote is the first piece of work a builder does for you. If it arrives late, is a single figure with no breakdown, or does not mention exclusions, that is a preview of the documentation you will receive for the rest of the project. A builder who takes the trouble to price properly tends to run sites the same way.

ORT Constructions is a licensed Sydney builder with structural carpentry and concreting capability in house, working across renovations and extensions throughout Sydney. If you have plans, send them through and we will price the same scope you are giving everyone else.