Advice on home extensions

toadstool 23 February 2010 10

We are looking at some modifications to our existing house. Primarily creating an entrance, extension of master bedroom (including expanded/remodelled WIR and ensuite) and enclosing existing pergola to make sunroom. We’ve had a ball park figure of $30K for entrance, $100k plus for master bedroom and $100k plus for sunroom. We have done minor renovations ourselves in the past but not to this scale, however these figures appear very high especially when you see advertising for knockdown rebuild of an entire house starting around $250-300K. Does anybody have advice on realistic figures for this type of extension?

Also, it appears from what we’ve read on other building forums that larger companies will typically quote higher figures to get the project falling in the scope of their interest. If this is typical, we love to give our business to a smaller builder who still do a good quality job for a more realistic price. Any suggestions or recommendations?

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10 Responses to Advice on home extensions
Steph101 Steph101 5:54 pm 26 Sep 17


We used Luke from Fresh Renovation for our ensuite extension and found him great to deal with you can see the site at or give luke a call directly on 0431135146.


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kean van choc kean van choc 4:31 pm 14 Mar 10

Sorry Toadstool, no suggestions or recommendations. But I can empathise and wish you good luck! This renovations business is fairly nerve racking stuff! We just want to update our bathroom and the cupboards in the laundry and bedrooms – fairly small scale compared to your endeavors – but find the choice of companies offering these services overwhelming. We’re thinking of using A&J Bathrooms and then discussing the cupboards with a few local cabinet making firms. Will report back on the outcomes (good or bad).

dinkyPhuong dinkyPhuong 4:02 pm 11 Mar 10


To help me figure out how competitive that Evans Building has quoted, could you tell how much it cost per square metre i.e. 1500/m2?

mutley mutley 10:33 am 26 Feb 10

We have had work done recently by Evans Building and are very happy with the result. The quote was competitive and they provided some good input into the designs we had put together. The son, Jason, did a fantastic job on our ensuite and would recommend him very highly for any tiling work.

Holden Caulfield Holden Caulfield 9:39 am 26 Feb 10

Hmm, I thought (was hoping) there would have been more responses to this request…

aidan aidan 1:17 pm 23 Feb 10

I’m at the beginning stages of a house extension myself. We’re adding a 4th bedroom+ensuite, rearranging the living area (moving a bedroom and making that space into north facing living) and enclosing a 3mx3m porch (making it part of the new living area). It was costed at $130K, but we’re knocking $10K off by doing the painting ourselves. All up we’re adding about 40 square metres and doing some significant internal rearrangements.

The first thing the builder said was “You know you won’t get your money back, don’t you?”. He just wanted us to be realistic about our expectations and said we should only extend because we wanted to live in our house and we liked it. If we didn’t we shouldn’t bother and buy a more suitable house.

It is expensive to extend, but the if you do buy decide to move instead you’re burning $20-30K in fees and charges. It is not a straightforward decision. In the end we looked for other houses to buy, couldn’t find any that were suitable and decided to extend.

Holden Caulfield Holden Caulfield 10:46 am 23 Feb 10

Just finding someone who understands basic customer service, or who will give a damn quote would be a nice start. AAAAAAAAAAAAAAARRRGGH!!!!

Deano Deano 9:47 am 23 Feb 10

Residential building with a standard level of finish should cost you around $1,000 – $1,500 per square metre. High levels of finish can run to around $5,000 per square metre. This figure is for an entire house and includes roofing, flooring, internal and external walls, plumbing and electrical. Renovations are generally a bit more expensive per square metre due to the additional work in removing the existing building material and typically involve high cost areas of your house such as bathrooms. Renovations involving structural modifications are way more expensive.

In any case, unless your sunroom is something like 100 square metres and going to be fully replaced, $100k is way over the top. There is no way it would increase the value of your house by that much.

Our neighbours have also been quoted ridiculous figures for their house extensions. Its mainly because builders can make more money by buying land and building spec homes for sale where the selling price is way above the construction costs. For renovations they can only charge for time and materials, so they quote inflated figures on the basis that they don’t really want the work unless you’re prepared to pay them the equivalent profit.

spinact spinact 9:38 am 23 Feb 10

For reasons unknown to me (and most non-builders) rennovations and extensions end up being more expensive than building from scratch. That’s why so many developers knock down old but perfectly good houses with potential and re-build. It’s just not worth there time and effort and they won’t get the financial return.

The master bedroom extension sounds the most complex as it possibly involves moving existing plumbing? But without more details it’s hard to say whether 100k is on the money or not. 100k for a simple sunroom seems a little expensive though.

My advice would be to get as many quotes as you can and don’t use a ‘yes man’ builder (one who blindly does what you want without offering suggestions). At the risk of sounding like a new age hippy, don’t use anyone who gives you a bad vibe. Women are usually better at picking up on ‘negative vibes’. I ignored my wife’s ‘funny feeling’ about a tradie and paid the price, he was crap. Only made that mistake once.

As a price comparison for you, a few years ago we paid about 110k for a double garage and loungeroom extension.

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