# Forum Contacts & Links Estimating & Quoting  Extension to house - Owner Builder

## dkhawkey

Hi, 
I want to build an extension to my house.  I have asked a few building companies and they have quoted from $100k - $120k, which is simply not worth it for the value add it would give my house.   
I've run up as detailed a quote as I can if I go Owner Builder and contract the work in.  I work it out at $34k including everything I can think of from slab to roof and all internal components.  I'm sure there are loads of things I haven't accounted for, so please tell me what I've left off, or if you notice anything where I might be way off.   
I've also included a simple plan of the extension down below.   
Thank you!  Bedroom New Build     Materials Qty Cost Total  Bricks 3600 $0.75 $2,700.00  Cement and Sand 320 $16.00 $5,120.00  External Render 200 $17.00 $3,400.00  Slab (Installed) (m2) 30 $90.00 $2,700.00  French doors 1 $1,400.00 $1,400.00  Windows 1 $1,000.00 $1,000.00  Roof Tiles (m2) 30 $50.00 $1,500.00  Roof Trusses 5 $100.00 $500.00  Gutters 1 $150.00 $150.00     $18,320.00  Labour Hours $/hr Total  Remove pavers 8 $40.00 $320.00  Foundations 8 $40.00 $320.00  Brickwork (Cost per brick) 3800 $1.50 $5,700.00  External Rendering 24 $40.00 $960.00  Remove Window to walk in robe 3 $40.00 $120.00  Roof Installation 40 $40.00 $1,600.00  Gutter Install 16 $40.00 $640.00     $9,020.00    Bedroom Internal     Materials Qty Cost Total  Internal Plaster 30 $17.00 $510.00  Internal Paint 1 $185.50 $185.50  Carpets (Installed) (m2) 30 $100.00 $3,000.00  Ceiling Boards 10 $16.87 $168.70  Cornices 6 $10.00 $60.00  Aircon (Installed) 1 $1,000.00 $1,000.00          $3,864.20  Labour Hours $/hr Total  Internal Plastering 24 $40.00 $960.00  Internal Painting 24 $40.00 $960.00     $960.00   Bathroom     Materials Qty Cost Total  Toilet & Cistern with soft close lid 1 $365.00 $365.00  Double Vanity (incl basin and cupboards) 1 $1,500.00 $1,500.00  Shower Enclosure 1 $600.00 $600.00  Shower Head 2 $73.00 $146.00  Shower Waste 1 $15.00 $15.00  Vanity Taps 2 $168.00 $336.00  Vanity Waste 2 $29.00 $58.00  Towel Rail 1 $126.00 $126.00  Shelving 1 $150.00 $150.00  Floor Tiles (m2) 4 $40.00 $160.00  Wall tiles (m2) 12 $40.00 $480.00     $3,936.00  Labour (Hours) Hours $/hr Total  Brick up old door 4 $62.50 $250.00  Plumbing shower, toilet and basins 16 $62.50 $1,000.00  Electrics (heat lamp and downlights) 3 $62.50 $187.50  Plaster new wall 4 $62.50 $250.00  Wall tiling 16 $62.50 $1,000.00  Floor tiling 8 $62.50 $500.00     $3,187.50   Other Costs     Draftsman  $1,000.00 $0.00  Designs  $200.00 $0.00  Move the drain  $1,000.00 $0.00  Council Approvals 1 $200.00 $200.00     $200.00

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## sol381

waterproofing and electrician seem to be missing...also you might need someone to lay the roof tiles.. battens are also needed..skirting and arch in bedroom... insulation for walls and ceiling... also is it brick veneer of cavity brick.,. if its cavity you need to add some pine framing ...I also see that the floor area of your bathroom is only 4m2.. Im not sure how you can have a double shower, double vanity and toilet in such a small area.also if you can get a plumber to do a bathroom for $1000,good luck... most are at least $3,000 for a bathroom..from the plan it doesn't seem like you have much room between the shower and vanity...also if you can get common bricks for 75c and someone to render for $17m you're doing very well..thats just a few things i see .. 
I wish you all the best with your reno but make sure you have your costings   done properly.. even the best of us can get it wrong and its very easy for things to add up..after you've got a total id add 20% just too be sure

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## dkhawkey

Thanks for the response.  All good points.  I do plan to add contingency of at least 20% to cover myself.  I have a bunch of close mates that are all plumbers which is why I have gone a bit lower there.  I've allowed 2300mm in for the bathroom width, so 1m for the shower, 800mm gap, and 500mm for the vanity.   
I'll add in your other points.  Thanks again for the response.

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## OBBob

Some of the pricing looks a bit light on to be honest, in both the materials and the labour. I'm not too sure of the rates but for example the tiles ... allowing 4sqm of tiles is not sufficient because you will have losses due to the cuts. Then the labour ... they maybe the hourly rates but in reality it may be hard to get trades to come and do a job for $250 ... there may be travel etc. added if it's that small. These items shouldn't be covered by your contingency ... these are known unknowns, contingency is for the unknown unknowns, which are bound to arise.  :Smilie:   
Every time I nick off to Bunnings in the middle of job I seem to spend $100  :Shock:  ... so just be aware the extra little bit you need to do the job also add up.  
Also noticed you don't seem to have the OB licence cost (I think there is one), you may need an OB course, you'll probably need a building surveyor (inspector), which wouldn't be covered by that council cost, you'll definitely require additional OB insurance ... and you should always allow for tools because never will there be such a good excuse again!  :Smilie:  
Good luck with it!

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## dkhawkey

Thanks for the reply.  I'll add in all the OB costs.   
I'm glad I'm not the only one who loves to spend at Bunnings!!  Might have to also add a line item for 'Tools' in the budget!! 
Thanks.

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## barney118

I hope you have deep pockets as banks don't like OB.

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## OBBob

> I hope you have deep pockets as banks don't like OB.

  Perhaps he doesn't want / need a loan.

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## shauck

There's so much missing from this that I don't know where to start. You could get a quantity surveyor to do this all for you. Don't know what they charge but worth talking to one and find out.

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## m6sports

I recon as OB with additions allow $1000 per sq meter if your doing a lot of the work by yourself, so your 6x6m reno would $36k if you getting someone to do it all for you mulitply that by 3 and you not far off your quotes, as when ever I've worked out a builder doing things for me it seams to be 3 times the prices of the materials. I know this is vague but a good starting point but as Shauck said you can pay people to do the working out for you  
to give you an idea of prices I pay 
20sq for gyprock installed set and sanded 
$100 per hour for sparkle and his apprentice plus materials 
$4000 for a whole house to have all new plumbing installed this included 2 bathrooms 
$1 per brick laid 
$40 per hour for a chippy
rendering can differ in price but allow between $40-50 per sq meter  
have fun if you start and are doing OB as trades can be very difficult to work with the only advice is don't go with the cheapest Quote but with someone that answers there phone. Half the difficulty is getting them to call you back 
and once you find a good trade stick with them for life  :Smilie:

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## shauck

> and once you find a good trade stick with them for life

  Yeah, for sure.  The guy I usually use for stump holes or small excavation work has recently gotten a full time job. There's plenty of guys up here to go to but instead, for the time being, he'll do jobs for me on weekends. I hate working weekends but I'll do it to use him. He accepts my fussy ways.

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## METRIX

There is a lot of information missing from your estimates, yes in a perfect world you could nut it down to the $1 value, but this world is not perfect, and doing any building work is far from perfect.
Facts and figures don't tell the entire story, as soon as you pull a wall / roof apart and start digging holes in the ground, your going to come across a lot of problems you cannot currently see, each one of these problems will require money to repair it. 
Plus the stress you will go through trying to do the work, come up with a solution to every problem you come across, if you don't put any value on that time, or have contingency in place, such as you might have a trade booked to come out in two days, you are currently finishing off a particular part of the job, an unexpected problem arises, this costs time and money to rectify, then your trade that was due in two days needs to be put back for a week, they cannot make it in that week, so need another 4 days to get them, this has flow on effects to other trades etc, days run into weeks because you are using these trades for the first time so you may not be on their priority list for someone who uses them all the time. 
Sure it's only a small extension your doing but don't underestimate how costs can blow out quickly, as OBB said, a simply trip to Bunnings will cost you $100 - $200 to get something missing, and you will be making a lot of these trips. 
Don't let anything dismay you from doing what you want, it's a fantastic opportunity to do an extension etc to your house, you will learn a lot, you will get really peed off with stuff along the way, you WILL waste money, but you may also save some here and there but at the end of the day you will have the satisfaction of knowing you were involved to some degree to achieving your goal. 
Other areas I can see your under quoting, small jobs where you have allocated little hours, you will struggle to find a tradie to do these for you in any reasonable time, as a 2 / 3 hour job is simply not worth the trouble most of the time, this is the realm of the handyman, which means you may end up with inferior finishes and actually cost more. 
A lot of the cost of hiring a builder to do the job for you is peace of mind, you tell them what you want, and they do it for you, they deal with the problems along the way and solve these for you, they have the trade contacts to get things done and can call on these trades to get tasks done at short notice when you could not, they know what's right and what's wrong, you can spend hours or days trying to solve a problem. 
It allows you to go to work do your job and earn the money to pay for it,

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## intertd6

I would recheck your calcs, I just glanced & picked up an error in the total of the 8 or so items after bedroom internal, $40 / hr is less than wages so your going to be hard pressed to find anybody that isn't dodgy for that rate.
regards inter

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## paddyjoy

Agree with the others, not sure where you are based but here in Sydney the cheapest trade I have ever hired was $93/hour, most are around the $100-$120 mark after you add in call out/travel fees. 
Council fees seem pretty light considering they will probably want a site survey done etc which can cost up to $1k alone. 
Also delivery costs and waste removal can add up pretty quickly.

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## METRIX

> A 
> Also delivery costs and waste removal can add up pretty quickly.

  Shop at H&G they have free delivery for basically anything they sell, had a client wanted a particular flat range hood exhaust system, H&G were stockists (or supposed to be). 
She ordered it over the phone, (they special ordered it) then they delivered it for free (she was only 15 minutes drive from them) same for anything else they sell, The guys at Brookvale delivered 1 x entry door to Hornsby cost $350 delivered free, saved me a trip to Brookvale, although could have got it from the Green Monster but preffered not to. 
Bunning's don't free deliver no matter how much you buy, the door was actually cheaper at H&G than Bunnings.  :Biggrin:  :Biggrin:  :Biggrin: , her range hood exhaust was again cheaper at H&G than anywhere else except WA which they would not send it. 
Agree with waste charges, these can get out of control very quickly, I have a mate in Melb, the skip bin fees there compared to Sydney are heaps cheaper.

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## paddyjoy

> Shop at H&G they have free delivery for basically anything they sell, had a client wanted a particular flat range hood exhaust system, H&G were stockists (or supposed to be). 
> She ordered it over the phone, (they special ordered it) then they delivered it for free (she was only 15 minutes drive from them) same for anything else they sell, The guys at Brookvale delivered 1 x entry door to Hornsby cost $350 delivered free, saved me a trip to Brookvale, although could have got it from the Green Monster but preffered not to. 
> Bunning's don't free deliver no matter how much you buy, the door was actually cheaper at H&G than Bunnings. , her range hood exhaust was again cheaper at H&G than anywhere else except WA which they would not send it. 
> Agree with waste charges, these can get out of control very quickly, I have a mate in Melb, the skip bin fees there compared to Sydney are heaps cheaper.

  Agree they are brilliant, I use them for bulky stuff, they have no problem delivering even just one sheet of gyprock or blue board. Apparently they just have a fleet of trucks, the guys there told me they would deliver 1 screw for free to anywhere in Sydney lol. I reckon if they set up a decent website with online ordering they would pickup more customers than they could handle.

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## phild01

I buy the plasterboard from Brookie H&G but it is dearer.  But works out the same or cheaper when the delivery cost by others is factored in.  They can be negotiable on price as well.

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## phild01

> the guys there told me they would deliver 1 screw for free to anywhere in Sydney lol.

   :Blush7: I'm guilty, they delivered a packet of nails to me for free, and from Brookvale, their local Hornsby store didn't have it.

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## heavytrevy

all the tiling rates are way off as well

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