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Small Underfloor Excavation Job

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  1. #1
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    Default Small Underfloor Excavation Job

    I would like to excavate an area 1.5m wide x 2.1m long x 850mm deep under my house (in Inner West Sydney), adjoining my underfloor workshop, and install a Saniflo Toilet and Basin.
    Excavation machine access is not possible so I'm looking for hand excavation labour using electric hand tools.

    The work involves cutting through 50-90mm concrete to get to the clay. Remove 2.7cubic metres of clay to 100mm below the existing workshop floor then laying a concrete slab finishing flush with the workshop floor. With a concrete saw and a jackhammer with clay spade attachment the breakup and loosening of the material can be achieved. It is then shovelled into a barrow and transported up the side passage to a skip in the front yard. I'm 68 and although in my mind I feel confident in doing this task, I think a couple of fit and strong, young blokes would be more efficient. I would estimate the work could take 7-10 days without busting your gut.

    I put the job on Hi Pages stating that machine access was not possible and they recommended 3 companies. The first one sends me an SMS asking what size machine do I want !
    The 2nd calls and says he will visit to look at the job in the afternoon, but doesn't turn up, or call to explain why. The 3rd simply doesn't contact me at all.
    I also searched the internet for hand excavators and finally found someone who quoted more than $10,000. My budget will extend to $5000 so that quote was rejected.

    My questions to this Forum are:
    1. Should I keep looking for excavation companies in Sydney that do small jobs? (Perhaps I need to review my budget too.) Can anyone suggest a company?
    2. Can I find a couple of fit, young, experienced labourers and supply them with the equipment (Saw/Jackhammer/Clay Spade/Wheelbarrow/Skip.) Does anyone know where I could find such people?
    3. Do I need to have an Owner Builder's licence, an ABN and then withhold tax etc (Which I did back in the 1990's when I Owner-built the house extension and hand dug my underfloor workshop.)

    Thanks in advance.

  2. #2
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    Have you looked at small composting toilets yet?
    It sounds like a lot of work and a large investment. Why this Saniflow system in particular?
    It does sound like a job nobody will want.
    Conveyor not a couple of wheelbarrows is my first thought
    "A big boy did it and ran away"

    Legal disclaimer denying responsibility to be inserted here.

  3. #3
    Community Moderator phild01's Avatar
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    Probably hard to find strong lads these days prepared to do manual hard work.

    Will the excavation undermine any part of the house foundations!
    Saniflo type systems work well for this type of thing.

  4. #4
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    This is the situation.

    * 2 Brick piers rest on a concrete slab that formed the old outside laundry floor which was built over with in 1992. Adjoining that floor was an outside pathway...hence the two different thicknesses of concrete.
    *The new lower floor area will be lined with brick to provide some stability around excavated area and concrete floor slab will finish flush with Workshop floor.
    * Distance from edge of brick piers to edge of preferred excavated area is 350mm. I can increase this to 750mm and reduce width of excavated area to 1.0m. What is minimum distance to piers? I've read somewhere that it is based on a 45Degree from edge of piers so some maths required here.
    *Height to main underfloor timber bearer is 1.9m
    *Saniflo Toilet is the most suitable option.
    Attached Thumbnails Attached Thumbnails proposed-excavn-area.jpg   proposed-excavn-area_li.jpg  

  5. #5
    4K Club Member Marc's Avatar
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    Don't bother with the on-line job websites, they usually attract the least suitable people.
    Plenty of strong lads in the concreting industry. Call a local concreter and don't give too many lengthy explanations. What you want is for the conceter to come and see the job. Like you said it is perfectly feasible to be done by hand, just needs to be assessed properly and not by on line photo.

    I remember not long ago ... well some years ago, a small ad advertising a group of new zealanders that offered excavation by hand for cases like yours.
    Whenever you find yourself on the side of the majority, it is time to pause and reflect
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  6. #6
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    Somebody who specialised in this sort of work might already have the conveyor etc. I recall a television program called "Selling Houses" that had an episode with a similar set of circumstances, perhaps those Kiwis Marc mentions?
    "A big boy did it and ran away"

    Legal disclaimer denying responsibility to be inserted here.

  7. #7
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    Call an underpinner.

  8. #8
    1K Club Member Pulse's Avatar
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    Default Small Underfloor Excavation Job

    gumtree often has backpackers looking for work, otherwise drop off a flyer at the local uni or backpackers


    pat

  9. #9
    3K Club Member johnc's Avatar
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    I'd try underpinners, that job would be a walk in the park for those guys.

  10. #10
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    I tried an Underpinner. Couldn't even get him to quote before March !
    Excavaters don't want to do hand work and a machine won't fit into my workshop.
    I'll look at Concreters next, but I hate searching and waiting for quotes that are probably outside my budget.
    Labourers with some experience are an option but the issue of insurance in case of accident worries me.
    I will most likely end up doing it myself and taking my time. Bunnings sell the Full Boar 1700W Demolition hammer for $480 plus a Clay spade for $45. Hiring something for an extended period will be costly. I'll keep you posted.

  11. #11
    4K Club Member Marc's Avatar
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    Cheap demolition hammers are a bit of a gamble, however from the ultra cheap, I have good reference from my plumber son in law. He bought a Baumann after his Hitachi packed it in and tells me he uses it every day with good success. Baumann, not Baumer, Baumr, Baum-r or similar
    https://www.vektools.com.au/baumann-...mer-1600w.html
    Whenever you find yourself on the side of the majority, it is time to pause and reflect
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  12. #12
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    Just an update on my job.
    I bought a Demolition Hammer from Bunnings last week (Full Boar brand for $299 + Clay Spade $45) and it's a great value for money unit.
    Very powerful and effective. It turns out there are 3 layers of concrete (a total of 160mm thick) over dirt then clay and as you can see from the attached picture, I am halfway through the concrete layers and that's after only a couple of hours.
    I should make good headway this week and then begin the task of shoring up the edges. Fortunately the two piers are well supported by the 160mm thick concrete pad but I'll put a metal support under the front edge of the pad and then prepare formwork around it and fill with concrete, burying the support post within the concrete fill.
    demo-hammer.jpgprogress-1.jpg

  13. #13
    Community Moderator phild01's Avatar
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    Thanks for the update.

  14. #14
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    Interested in how this is coming along.
    Always interested in other folks projects.
    "A big boy did it and ran away"

    Legal disclaimer denying responsibility to be inserted here.

  15. #15
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    Hi Moondog55,
    Thanks for asking. I'd been so busy doing the job that I'd forgotten to post up progress pics so here they are:
    01_day1.jpg Day 1 of Project
    02_half-way-excvn.jpg Half-Way Point in Excavation
    03_excavation-completed.jpg Finished Excavation
    04_removed-clay.jpg Clay Removed
    05_removed-concrete.jpg Concrete removed
    06_formwork-stage.jpg Formwork Prepared
    07_concrete-poured.jpg Concrete Poured
    08_squared-lined.jpgWalls Squared & Lined
    09_tiled-grouted.jpg Walls & Floor Tiled & Grouted
    10_test-layout-facilities.jpgToilet & Basin installed

    Next stage is building and installing the doors and fitting out the storage area around the toilet area.
    Pics in next posting

  16. #16
    Community Moderator phild01's Avatar
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    Be wary about bridging the ground work with the house structure, termites would love that.

  17. #17
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    Lining the storage area and fitting the doors was the final stage.
    11_lining-storage-area.jpg Storage area Lined with Plywood
    12_fitting-doors.jpg Storage Cupboard Doors Fitted
    13_job-finished-painted.jpg Doors Finished and everything painted

    As you can see... quite a change from the rough and ready area that existed before. Planning the interior of the storage unit is the next project to maximise the available space I've created.
    The 240V Saniflo Toilet is the perfect solution for a downstairs area as it literally pushes @@@@ uphill into the main sewer line which runs above ground and across the back of the storage area. No more rushing upstairs for a pee or doing it in an empty container.
    Cost of the Saniflo Compact is $1560 at Bunnings but I got a shop room floor model from my local plumbing supplier for $1200. Installation of the toilet and basin (which empties into the toilet tank and gets pumped out ) was $880 so it was a very economical proposition. Installation of a power point was a short cable run from a power point directly upstairs.
    I had help with the excavation and concrete pour from a mate and the only quote I managed to get from a professional for the excavation and slab was $10,000.

    The total cost of my project from start to finish including all materials used specifically in the job was $5853, and it would have cost me less if I didn't make the mistakes a novice makes.
    It just shows that all you need is a vision, the determination to keep going and apply what limited knowledge and experience one has to a task. Of course YouTube videos and websites like this one make up the other ingredients to complete a project. Thank you to all who offered help and encouragement.

  18. #18
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    Good point phild01.
    Regular inspections, an awareness of the potential problem and vigilance combined with that fact that I'm down there everyday will allow me to keep things under control.

  19. #19
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    Nice result.
    So how long did the excavation take for you and your additional help?
    (days/hours)x $50 per hour ave = $ saved

    Cant see the pathway to carry the stuff out...but didnt look that hard of a job for 2 young blokes to easily do.
    Its certainly not a $10,000 job - equiv of 28 days of effort at 7 hour day
    I'd hazard a guess to say your 7 days (for 2 young blokes) would have been close to the mark??

    If you r willing and able with a few skills and a keen eye for detail, it can certainly pay off doing some stuff DIY.

    Currently laying crushed rock, boxing up, plastic and reo for 300 square meters (30 cubes of concrete) around the house veranda and drive with some dropped edge beams in 3 places
    ....its a pain in the a@$e particularly cutting the steel and bent over tying it all together...probably taking 2 to 3 times longer than a pro but anticipate to save btwn $8k to $12k
    ...and keep telling myself that to stay motivated and just chip away at it!!!!

  20. #20
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    Hard excavation work completed in 5 days with jackhammer and a clay spade. Tough work for a couple of 68 year olds out of condition. Removal required bucketing it up two steps and out through a 3/4 height doorway into a barrow then wheel 50m up the side of the house and empty onto the floor of the carport. I can tell you we were stuffed at the end of each day and the beers were most welcome. No access for machines. Totally hand based manual work which is probably why they wanted so much to do it. Of course that price also included bricking up the sides and laying a slab. We poured concrete sides and a slab by filling buckets up from the Concrete Taxi service in the street into a wheelbarrow then taking the buckets into the cellar from the wheelbarrow outside the door and emptying them into the 150mm cavity around the edge of the opening. When the formwork blew out on the left hand corner we had to stop the pour, but before it hardened, I carved it back into some semblance of 90 degrees and then strengthened the formwork for a second pour on the walls. For a couple of Mug DIYers who'd never done this sort of thing before, we got there in the end.

  21. #21
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    Looking great
    "A big boy did it and ran away"

    Legal disclaimer denying responsibility to be inserted here.

  22. #22
    Golden Member havabeer's Avatar
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    nice work.

    i needed an ag line dug around the side of my house and similar problem of no way to get machines in. in the end I found a concreter who's labourers where just looking for some cash work so I got 3 of them around for $100 each a day, we ended up moving 7 cubic meters of clay/dirt by hand using buckets and a barrow so two or so days of the 4 of us working was worth the money.
    Remember if you don't sin, then Jesus died for nothing

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