Collapased Pipe Under Concrete Patio

I have a plumbing problem as follows:

  • "Plumber called out to investigate reports of a blocked drain. After testing points inside the house, it was apparent the blockage was located between the overflow relief gully and main shaft at the rear of the property. They managed to clear the drain by way of high-pressure water jet upstream of the main shaft.

  • Once cleared they used the CCTV and locater to identify a collapsed section of pipe under the rear concrete patio. They used camera downstream of the shaft to find a break at the base.

  • To rectify they will need to remove a section of the fence to gain access for their machine, cut and remove a section of the concrete patio, excavate and repair all effected pipework. Once complete they will backfill, level and clean site of all debris."

  • Cost: ~$11k

I'm in the process of obtaining additional quotes.

See attached pictures of location and inside pipe:

  • Are the plumber's comments consistent with the photos?

  • Can the plumber go under the patio via the soil behind it without having to remove a section of the patio?

  • Is the price reasonable for the Sydney North West?

  • Are there any cheaper ways to fix the problem?



    Cheapest solution is to ignore it. Not great advice but have you figured out where the leaking water is going and whether it is causing damage to other parts of your property? How long do you think its been like this and you hadn’t noticed until the blockage occurred?

  • +6 votes

    Are there any cheaper ways to fix the problem?

    1. Quick trip to Bunnings for a sledgehammers
    2. Quick trip to Dan Murphys for a slab of beer
    3. Long day smacking concrete.
  • +4 votes
    1. Check if the pipe can be relined from inside
    2. Redirect the pipe to run in the garden area (if the pipe fall is good enough) and not touch the patio
  • +1 vote

    Go full WW1 Aussie Tunnellers, Dig a shaft next to the patio concrete, there across to the broken pipe, and replace from there.

    Alternatively do as Zeggie suggested above, smash your patio concrete up yourself, it's not the big. Replace the pipe, prepare the ground, and get someone in to pay a new patio. Will be a lot cheaper than $11k.


    Is it causing water to seep into the ground?

    Is it just concrete pavers or decorative concrete? If it's pavers, remove all pavers to expose the ground, remove vapour sheet and dig up the ground, expose broken pipe, replace. It shouldn't cost that much.

    If it's concrete, then yes, more than likely the whole pad needs to go, excavate the ground to expose the pipe, replace pipe, fill in and lay new vapour sheet, concrete.

    It could potentially cost more in the long run where it's compromising the ground and you start to notice cracks through through the house.

    Would definitely reach out to see if you can get better quotes though. Method of repair could vary.

    EG: can the plumber get under the slab without compromising the gound to remove the exposed pipe?

    Lodge a claim through your home insurance for exploratory work to recoup costs for your CCTV leak detection.


      Patio is just stenciled concrete.

      I will check the possibility of going under the pad.


        It depends on how deep the pipe is under the pad.

        Since it's stenciled concrete, digging under the pad will ruin the ground's integrity and compromise the pad more than destroying it and re-laying stenciled concrete.

        Is the concrete linked back into the house? If so, then yes, around $11k's work seems to be about right, but still get additional quotes.

        If you know someone that can lay new stenciled concrete, then a suggestion of home DIY may be a way to go. The pipe is the cheapest part of the whole process, just getting to it, and rebuilding it is what's gonna hurt your pocket.

        Do you want to keep the concrete pad there or change it up? Like a raised timber patio or something else? Many options for after repairs.


          It depends on how deep the pipe is under the pad.

          Will find out.

          Is the concrete linked back into the house?

          No, it's separate from the house slab.

          To be sustainable I'd like to leave the pad as is if possible, but good point about going under will compromise the ground integrity.

          I'll explore relining options as well.

  • +6 votes

    $11k is absurd, but the cheap option is to do most of the work yourself.
    People charge this because they need to get a carpenter/fencer to remove fencing, hire a digger and driver, excavate, fix the pipe, hire a concrete, hire a tiler, get the carpenter back. Nobody wants to do a job for less than $1000, plus the original plumber needs to have some contingency in case something unexpected happens.
    Smashing the paving up will take an afternoon, fixing the pipe will either be easy, or a few hundreds from a plumber.
    Re-concreting will take a morning. Tiling is fiddly, maybe $600 - $1000 to get a tiler to replace the ones you smashed up.

    But you will have to organise and do part of the work to save $9000.


      Patio is just stenciled concrete.

      I will check the possibility of going under the slab.

      They said something of around 4 days' work.

  • +2 votes

    Family member had same issue and similar quotes. Go kenards or bunnings rent your self concrete saw easy to use and do it your self dig hole . F*** these rip of bastards


      They aren't rip-offs. They have to pay for a lot of sub-contractors and if quoting cover their risk. Plus they are working with poo.

      He might get it cheaper if he worked on a do and charge basis but if it goes pear shaped then maybe not.

  • +3 votes

    This is possibly a once in a life time opportunity to hire a excavator and destroy shit lol.

    Get ya self down to Kennards hire. No manual labor required. Just don't go to crazy or your next thread will be looking for a new home lol.

    1t Excavator Should be easy to fit through a gate

    Concrete breaker


    Get a concrete saw, or possibly an angle grinder with a diamond blade.
    Break out the concrete with a big hammer, bar and chisel.
    Get a plumber in to repair the pipe.

    A fair bit of your price will be in reinstating the concrete, especially with the stencilling.

    You can cut costs by digging the hole yourself and repairing the hole afterwards.


    Buy/rent a jackhammer and do the job yourself. Easy! Would take me a day.


    There is not cheapest solution. Either outsourcing the work and you money, or taking the work and risk yourself.

    If you believe 11k is too much, ask two more plumbers for quotes. It might get you somewhere, but it would not be half price of the original price.


    What depth is the pipe?


    We had a similar issue a few months ago. As we did most of the digging work ourselves, the plumber's charge was about $800 in total, including use of hydro jet machine, drain camera, labour and all materials.

    In our case, the pipe was about 50cm from the ground surface.

    After the pipe was fixed, we paved the area instead of concrete.

  • +1 vote

    Oh this brings back nightmares from last year.
    I had this issue.
    BEFORE you do any DIY check with your insurance company as to what they'll cover.
    If you can remove the fence yourself ok but check with your neighbours first because if it doesn't go up properly you could have issues
    If your insurance doesn't care I agree, break up the concrete your self get the pipe repaired (With more quotes) and concrete repair.
    In my case I couldnt do this.
    If I broke up the concrete the insurance wouldn't cover repair in case id done more damage to the pipe, thereby increasing their repair bill.
    I had to pay for the concrete to be pulled up but then ins paid for pipe and repair concrete. Good thing was when the concrete came up they found an additional split 30cm further down, would have missed it and had to do again if the concrete hadn't been pulled up.
    Also, fyi , if you've had a leak you can apply to have a discount on your water bill in most states.


      Insurance generally covers only damage from the leaking pipe, e.g. sewerage flowing back into the house, not the damage to the pipes and rectification itself. This is for houses - might be different for strata insurance.

      Is yours a house and who was your insurer?


    I have a plumbing problem

    To rectify they will need to remove a section of the fence to gain access for their machine, cut and remove a section of the concrete patio, excavate and repair all effected pipework. Once complete they will backfill, level and clean site of all debris."

    Sounds like you have a money problem as you know what the plumbing problem is.

    Get some more quotes and go from there.


    Can't you just lay new pipe around the concrete slab?


    Is it possible to run a smaller diameter pipe inside the old pipe?


      Relining - because pipe has collapsed plumber doesn't think this is possible (he does do this as part of his service).


    Brother Il tell you the cheapest way .. rent a concrete saw cut the patio into blocks 300mmx300mm . Use a crow bar to pop blocks up and remove them . Hand dig the the ground and expose the pipe so you can cut the damage out the more you dig the easy it will be to cut. You can use a saw or angle . Measure the pipes and head down to Reece . Talk to the guys there and ask them what they think should be called a quick connect . They might have another idea you could even call the plumber to do this part . Reconnect and put some blue metal around the pipe and backfill.shouldnt cost you more than 600 I think 10 hour job … The plumber you called is lazy .plumber in the family been helped him out for a while. Some jobs have to be hand dug even with easy machine access cause of electrical cables . You should watch a plumber dig they can dig to expose that pipe in 15mins after the patios cut


      What you wrote is exactly what they'll do in update below at $90/hour for 80 man hour days.


    Update after speaking to plumber:

    • The pipe has snapped 1.6m deep and base has snapped 2.3m deep.

    • Extent of damage means pipe can't be relined (in picture there is only part of pipe left) - plumber also does this; if this problem was identified years ago it would have cost say $2.2k.

    • Cost break down is approx $7.6k for plumbing services - 2 guys for 4 days @ $90 for 10 hours a day digging and filling after job completed. Excavator $1k; concrete saw $750, skip and supplies.

    • He said if problem was 0.5m deep it would only require 2 days work and hence almost half the cost.

    • Once excavated and pipe replaced, it will be covered with aggregate to avoid problems in future. Quote doesn't include replacing the part of the concrete that was cut and removed but the shape of the rooms at the back means that although the pad will be smaller, it still looks nice.

    The guy sounds professional and transparent and runs a 25 man business, which might mean that their charge out rate and hours are high (and/or he's factoring in a big risk margin), so I will investigate other quotes, and also check whether the pipe can be relined.


    Dig up the pipes on either side of the concrete and cut it and bypass the bit under the patio…


    Update: Broken pipes were replaced today for less than half of the first quote. I had another quote from another highly reviewed plumber for a few hundreds more than the plumber I went with but but it was still less than half of the first quote which gave me confidence that the plumber wasn't going to try to cut corners. He took one long day with two other guys to do all the work. He had budgeted for two days with fewer people but because of the recent rains had to try to do it in a shorter timeframe.

    One sour note - the plumber found cracked stormwater pipes as well and said he'd charge me for cost only, but when he sent the invoice added $400. I was able to negotiated this down to "cost".

    The first plumber had budgeted for 2x the effort/time and cost.

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