Owner building costings?

[zongatron]

Hi guys,

I am considering owner building an extension of about 60sqm, in mud brick, and must say that my materials costing comes in at a little under 30k. ( much like mahayleas in another post who built 120sqm for $500per sqm)

Every time i find a post on costing though everyone seems to agree that 1-3k sqm is about right.

As i will be doing the work mostly myself, after plans and councils i would be looking at about 35k ( to lockup with no finishing)

i will be laying the footings, laying the mudbrick, building the roof, laying the tin and doing the gutters... I already have all my doors and windows...

Am i missing something here as my costings are less than $500sqm, or does that all sound about right for materials

Does anybody see any holes in this plan?

thanks

[addo]

It makes some basic assumptions about materials handling, personal endurance, ease of construction... You'll also have to factor in the various fees along the way too (inspections and approvals, Owner-Builder course and Fair Trading permit).

If time is really of no consequence (retired, artist, alternative lifestyler etc), then the following comments don't apply.

Try to put some realistic unit rates for time on various processes - ie; digging a footing 350W×500D. How long to dig one metre of this? Or do you plan to get in an excavator? Where will excess materials go? Do you have financial stresses that could slow or stop the project at any point? Is that a "stable" halt to the project or would the existing work deteriorate? How many mudbricks in the structure? How long to make and cure each one? How are their materials procured and handled (mixed)? It's all time, effort and wear on tools and body.

However - I'm not wanting to be disparaging (truly) - just want you to be 100% aware of what a darned hard slog it can be!

Regards, Adam.

[zongatron]

Okay, a bit clearer picture hereforth and unto

Important to consider I am only thinking to lockup stage. And that I already have all my doors and windows for the design i have in mind
In my case, i am time rich + i am lucky ( its all relative ) enough to have a concretor for a neighbour who has a backhoe which i can dig my trenches with.
There will be a few expenses hiring labour for heavy beam work, but all in all quite a simple structure.

So far i have come up with this ->
Please and i mean--->'ppppplease....' correct me and caution me as to my mistakes here.

Approx 60 sqm in total

footing length all up about 30meters long + 100ml infill slab + steel
= 5-7k

mud bricks + mortar already quoted
= 5k

plans + council
= 5k

timber and steel and gutters for roofing (I am unsure) say
=7-12k

sparky say
= 2-3k

Soo to lockup about 30-35k? And if i have 45k in the bank, do you guys think i will be covered?
Does this sound about .................
or does it sound like in a few months time?

cheers

[OBBob]

Hi There, it's a bit hard without the design and it's also hard to know what point people know as lock-up. A few comments ...

-The sparky looks a little low (dependant on what his actual scope is at this stage I guess)?

-Do you have any wet areas that need plumbing ... bathroom / kitchen?

-If its under a permit I wouldn't have thought that you were allowed to do the roofing and guttering yourself (need a plumber)?

-Roofing cost depends on the deign ... but you say big beam work. One beam in my place cost over $1000, so you probably need to check if it's all fairly cheap stuff.

-Allow to hire some tools as required.

-Do you need stud walls to line the inside of teh walls of for internal walls? There'd be a few grand in pre-fab frames if required.

Otherwise, generally you are correct that there is a significant portion of the build cost in the labour and the risk. When you finalise your budget add a lump of contingency money because it is hard going, so that last thing you want is the pressure of having under estimated too.

Good luck.

[echnidna]

Keep in mind there are some things you are not legally permitted to do.

Roof works must be done by a plumber
Drains by a drainer/plumber etc

[addo]

True - in theory.

A lot of people do what I do, which is 9/10 of the rough in myself and leave the sparky or plumber to actually join the dots. Most are pretty happy to work like this, and often will correct a small error or modify for improved results quite readily. The big win is less outgoings for subtrades, by virtue of them being on site far less time.

Cheers, Adam.

[silentC]

If you rough in wiring without the sparky on site, technically you are breaking the law. If you can get him to sign your work off, well and good - it's him that is taking the risk in that case - he is essentially lying because he is meant to be on site to supervise. Not sure about plumbing.

[zongatron]

thanks guys,

Mud brick wont need any internal stud walls. Maybe one to divide another existing room to accomodate the new design.
Mates a plumber, so a few beers etc will get a lot done, and can probably do most myself and hed sign off as need be.

not sure on roof design. pricing trusses now for a quicker easier perhaps cheaper although undesired flat ceiling...
or perhaps some kind of cathedral. This would only be for the main front room which is looking about 6.5 x 5m which i would then link to the existing flat roof. Alternatively, a flat roof following all the way through ( cheaper again i would think? )

Sparky would be installing about 10-15 downlights, moving/adding three powerpoints, and moving two light switches, thats about it....

I have plenty of tools close by to borrow from neighbours, so that would be minimal also..

just costed aircell insulation so add.... 2.5k to retro existing and add to extension.
plus may need to replace whole roofing iron....maybe, see roofing iron post

thanks again people

[addo]

SC - to clarify - no connections made, wiring clipped off, brackets mounted, everything bundled/tagged. Same with the plumbing - lay the pipes out, elbows etc - no cuts or joins made.

Yes, both are possibly illegal (is wiring actually wiring when it's not connected?) but I'd argue it's a fairly petty point because everything is clearly presented to the subtrade.

Getting back to the OP - I am a big believer in over-spec'ing, so you may well want to consider another circuit or two from the main board. an in the short term, a couple of weatherproof GPOs for power outside while the building process is kicking off.

Regards, Adam.

[zongatron]

i will consider another board.
the house is already really small, 70sqm.
Not much going on here in regards to power usage.

i have a seperate board hooked up in the shed right next to the house so will probably drive most things from there..

thanks

[bricks]

If you rough in wiring without the sparky on site, technically you are breaking the law. If you can get him to sign your work off, well and good - it's him that is taking the risk in that case - he is essentially lying because he is meant to be on site to supervise. Not sure about plumbing.

Just raining the point that if you wanted to you could cut the chases, drill the holes for the cables to go through, etc. But I don't know of a sparky ( not saying it doesn't happen) who would let you run the cables and mount the power points/ brakets?

By all means have it ready for the tradesman so it's easy for them, it'll only save you money.

As for the roofing component, I think you might be a little light on there as well,

Rough pricing here in adelaide at the moment,

Roofing 760mm wide sheets at around $15-20 per meter
gutters- about the same,
Timber for roof , about $4-5 per meter.

You also hav'nt allowed for paint, trimmings, floor coverings and window finishes?

remember to add in costs for Fixings like nails, screws, glue's, liquid nails, gap fillers ect....

I've just knocked out a sliding door and gyprocked it up for a new kitchen reno.. costs were this....

Timber frame $32
gyprock $21.00

Stud adhesive-$4.30
Flexible gap filler- $7.24
nails-$10.90 box ( more than i needed)
galve clouts - $3.40
6 kg tub of plaster filler for flushing- $34.00
webbed tape for joins- $3.40

As you can see, and although ill have a small amount of materials left over, and alot of nails, the cost of the wall was greater in sundry items than for the main structure and walling materials,

My best advice is to plan for absolutely every cost you can imagine and then add 25% for extras, try to buy in bulk from the suppliers not the hardware stores, and allow for a skip bin to be out the front of your house during the building process- rubbish can very quickly get out of control when your renovating.

[montiee]

I've always been curious fella's. I know it's illegal but whats stopping you from running the wires and putting the points in and then getting a trady in to check everything over on the basis you had a disagreement with the original trady who walked out on the job? How will anyone truly be the wiser?

I mean I can see where arguements between owners and tradies result in them walking out on a 50-80% job because of the trady wasting time and wanting to run over budget. Hell I've thrown a few out myself when they made obvious ????ups and looks like amatuers despite the license. Surely you aren't going to rip out all the work.

[bricks]

nothing at all, you just need to convince the sparky, Im sure it has happened before.

[addo]

Jumping back to the beginning again.

Since the OP's questions have been flying thick and fast - financial, materials, costings...

It's time to seek the services of a draughtsman or architect. Once a concept is decided on, the actual working drawings will be a source of revelation. Many aspects will essentially build themselves as various mooted alternatives become either cost-effective or too dear. Working plans also allow sub-trades to quote accurately and bindingly. Just having a mental picture isn't enough for an amateur to progress beyond the speculative stages we've traversed in recent days.

Even unapproved plans that are very likely to be accepted by Council, are frequently an asset-builder. Approved plans, with estimates from an architect or QS and realtor's estimate of finished value, are a good tool to draw down upon or increase a mortgage.

There are a lot of people here willing (and well-qualified) to offer helpful comment. The further you get down the track with the above necessities, the more focused and effective their contributions are going to be.

Regards, Adam.

[OBBob]

As you can see, and although ill have a small amount of materials left over, and alot of nails, the cost of the wall was greater in sundry items than for the main structure and walling materials,

Completely agree! It's amazing how little it actually costs and how little time it takes to get the frame up and make it look like a building. It's all teh stuff that comes after that takes forever, is now where near as much fun and costs a packet!