# Forum Contacts & Links Estimating & Quoting  Extension m2 costs

## dazzler

Hi all, 
I would have thought this had been discussed before but I cant find it. 
I want to have an extension built to match the house.  Its a master bedroom/full size bathroom thats 9m x 4.8m all up. 45square metres. 
Weatherboard on perimeter brick with particle board flooring on brick piers, 400mm off ground.  It will be tied into the end of a gabled roof. 
What formula is used to estimate the costs?  Will be contracting a builder at this stage.  I imagine they vary and I am located in Hobart. 
Is it X $ per sq metre plus the cost of the bathroom? 
cheers

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## LSM

I'd assume ~$2500/sqm + $2000/sqm for bathroom areas as some rough numbers to start off with. We recently signed the contracts for a weatherboard extension of ~40sqm + 10sqm of internal reno including a ~9sqm bathroom that came in at ~$130k. That job had a few extra features too.

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## Sarah78

Hi all,  
Think about dong the work yourself i.e. being the project manager and organising the trades. For everyone... If a builder has quoted you $130k they are probably doing it for around $80k and the rest if profit for them...  
Best way would be to get an estimate done by an estimator, who will work out exaclty what it will cost and put it down on paper for you. Then you will be able to see if each trade is giving you a fair price...Saves time and lots of money if you have all the info on paper 
I can help anyone who needs an estimator...i wont advertise on here but email me if you want a good reliable person and i can refer you...

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## Wavenut

> Hi all, 
> I would have thought this had been discussed before but I cant find it. 
> I want to have an extension built to match the house.  Its a master bedroom/full size bathroom thats 9m x 4.8m all up. 45square metres. 
> Weatherboard on perimeter brick with particle board flooring on brick piers, 400mm off ground.  It will be tied into the end of a gabled roof. 
> What formula is used to estimate the costs?  Will be contracting a builder at this stage.  I imagine they vary and I am located in Hobart. 
> Is it X $ per sq metre plus the cost of the bathroom? 
> cheers

  Dazzler the cost for 45m2 extension at Canberra prices start at $198,000

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## Bedford

Wavenut, this is a three year old thread, I reckon Dazzler has sorted it by now.     

> Dazzler the cost for 45m2 extension at Canberra prices start at $198,000

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