Browse Forums General Discussion Re: Slab heave/ slab design/ engineering questions..... 2Feb 17, 2021 10:47 am Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Slab heave/ slab design/ engineering questions..... 3Feb 17, 2021 10:56 am StructuralBIMGuy @Cracking everywhere I would tend to back the 2nd engineer in. All he needs to do is match the cracks with his Analysis/Data while if you choose not to demolish you are left with a house not fit for purpose I would recommend you lodge a complaint with the building commission, Unless your in NSW where there is no Building commission. Hindsight is a wonderful thing and If you asked those questions before the slab pour you would have commissioned your own engineer chances are there was no one qualified on site during the pour Goodluck Thank you for the reply mate. He has drawn these conclusions by first inspecting the house and then looking over the slab design drawings which I provided him with. His conclusions weren't reached through monitoring of crack width etc. but more so analysing the drawings. Yes, I wish I'd known more and been more involved when I started this build. In hindsight I feel very foolish and naïve but I just trusted that my builder knew what he was doing. Stupid right? I do live indeed live in NSW. Thanks again. Re: Slab heave/ slab design/ engineering questions..... 4Feb 17, 2021 11:29 am Its easy money to turn up and say the slab had to be upgraded and now pull it down after the event Repairs and rectification work can only take place after movement has stopped Severity of cracks is a function of movement/time & other factors which need to be measured What you want to avoid is the legal costs and time delays and then wind up with a house that is repaired My2c, a building commission would be more sympathetic to pulling down the build... the legal system not so. Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Slab heave/ slab design/ engineering questions..... 5Feb 17, 2021 11:33 am StructuralBIMGuy Its easy money to turn up and say the slab had to be upgraded and now pull it down after the event Repairs and rectification work can only take place after movement has stopped Severity of cracks is a function of movement/time & other factors What you want to avoid is the legal costs and time delays and then wind up with a house that is repaired My2c, a building commission would be more sympathetic to pulling down the build... the legal system not so. Can a house with a non-compliant slab BE repaired? How would that work? Wouldn't it continue to move no matter what repairs are carried out? Re: Slab heave/ slab design/ engineering questions..... 6Feb 17, 2021 12:13 pm LOL most slabs I inspect for repairs are non compliant Track down another engineer that does structural repairs, no harm in getting another opinion. Lawyers tend to hire "pull it down" Engineers.. I tend to be the opposite in doing structural repairs In the mean time monitor the movement/cracking to see if it's getting worse, stopped, etc, that is something that you can do, measure and log the data yourself If you choose to hire a surveyor it will cost you every time he comes back. I suggest you seek more advice locally Cheers Chris Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Slab heave/ slab design/ engineering questions..... 7Feb 17, 2021 12:15 pm StructuralBIMGuy LOL most slabs I inspect for repairs are non compliant Track down another engineer that does structural repairs, no harm in getting another opinion. Lawyers tend to hire "pull it down" Engineers.. I tend to be the opposite in doing structural repairs In the mean time monitor the movement/cracking to see if it's getting worse, stopped, etc, that is something that you can do, measure and log the data yourself If you choose to hire a surveyor it will cost you every time he comes back. I suggest you seek more advice locally Cheers Chris Here is the chart showing how the slab is non-compliant. Sorry for asking so many questions but do you think this is something that could be worked with? Thank you again for your advice. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Slab heave/ slab design/ engineering questions..... 8Feb 17, 2021 1:23 pm Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Slab heave/ slab design/ engineering questions..... 9Feb 17, 2021 11:13 pm Sorry to hear you have slab heave and non compliant slab and great that you have come onto this site to increase your knowledge and many experts who have great expertise. Apart from an Engineer inspecting and commenting on the slab non-compliance, have other investigations taken place? What is causing the slab heave? Have the underground stormwater and sanitary pipes been checked with CCTV to see if there are broken pipes or water leakage? I have had an ongoing battle for 8 years. The builder completed 'bandaid' fixing but it kept getting worse, he stopped communicating denying responsibility. I hired a lawyer. He also recommended an Engineer and investigations (including floor levels and crack width etc) and report provided. Recommendation knockdown and rebuild due to significant structural damage and floor levels 154mm out of level, caused by non compliance. Lawyer recommended VCAT and estimate cost of $140k - $230k. I spent $1000's with appointments, letters, phone calls etc with the lawyer and was pushing VCAT, saying it was my only option. Because lawyer had sent letters to Builder, original Engineer and Geotech they all hired Engineers and they all came up with different causes deflecting blame from their 'party'. I decided to do my own homework. Read everything I could get my hands on. Noticed differences in Engineering drawings to what was constructed and obvious plumbing non compliance from the knowledge I was gaining. I sacked the lawyer. I hired a Forensic Plumbing company and wish I had done this 7 years earlier. Four plumbers with non compliance and significant non compliant underground plumbing. Stormwater pipe breakages that were fixed with silicon and then covered over, insufficient gradient, cracks and a broken sewer pipe. I submitted complaints to VBA (regulator in Victoria) and waiting for information regarding their investigations and actions for those responsible. I won't hold my breath. I am now out of my home as it is unsafe to live in due to significant structural damage. It will be demolished and rebuilt this year. There are many stories on this site regarding slab heave. Have a read, knowledge is power. Good luck Re: Slab heave/ slab design/ engineering questions..... 10Feb 18, 2021 9:43 pm Harts Sorry to hear you have slab heave and non compliant slab and great that you have come onto this site to increase your knowledge and many experts who have great expertise. Apart from an Engineer inspecting and commenting on the slab non-compliance, have other investigations taken place? What is causing the slab heave? Have the underground stormwater and sanitary pipes been checked with CCTV to see if there are broken pipes or water leakage? I have had an ongoing battle for 8 years. The builder completed 'bandaid' fixing but it kept getting worse, he stopped communicating denying responsibility. I hired a lawyer. He also recommended an Engineer and investigations (including floor levels and crack width etc) and report provided. Recommendation knockdown and rebuild due to significant structural damage and floor levels 154mm out of level, caused by non compliance. Lawyer recommended VCAT and estimate cost of $140k - $230k. I spent $1000's with appointments, letters, phone calls etc with the lawyer and was pushing VCAT, saying it was my only option. Because lawyer had sent letters to Builder, original Engineer and Geotech they all hired Engineers and they all came up with different causes deflecting blame from their 'party'. I decided to do my own homework. Read everything I could get my hands on. Noticed differences in Engineering drawings to what was constructed and obvious plumbing non compliance from the knowledge I was gaining. I sacked the lawyer. I hired a Forensic Plumbing company and wish I had done this 7 years earlier. Four plumbers with non compliance and significant non compliant underground plumbing. Stormwater pipe breakages that were fixed with silicon and then covered over, insufficient gradient, cracks and a broken sewer pipe. I submitted complaints to VBA (regulator in Victoria) and waiting for information regarding their investigations and actions for those responsible. I won't hold my breath. I am now out of my home as it is unsafe to live in due to significant structural damage. It will be demolished and rebuilt this year. There are many stories on this site regarding slab heave. Have a read, knowledge is power. Good luck Thank you for the detailed response Harts. Thus far I have had a building inspection and report, a full CCTV inspection of the plumbing (some of it is not code compliant) with accompanying written report and a structural engineers inspection and report that has found the slab is not compliant with AS2870- mainly because it's an H2 class slab and my soil is H2-D classification. If you sacked your lawyer, how did you get this result at VCAT? Did you end up representing yourself? Re: Slab heave/ slab design/ engineering questions..... 11Nov 16, 2021 8:22 am Apologies if I am hijacking the thread but I believe all involved may be of some help to me Our slab has now bee poured but I have found a discrepancy in the structural comps and structural plans used for the construction. This is set of slab comps where design engineer has used 1N16 as bottom bars for calculating slab strengths. Yes comps show that the capacities surpasses the design forces, however these numbers are based on the wrong sized bars. Assumes that builder has used N16 for rib reinforcement. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Below is the footing spec shown on the endorsed structural plans that builder used for ordering material and boxing up slab. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Questions:
Background - Class P waffle pod slab, controlled filled site with level 1 certificate by developer but independent soil testing revealed some areas have <50kpa bearing capacity, Engineers adopted perimeter bored piers costing me $$$$ that I shouldn't have been paying for. No piers in the middle under internal load bearing walls for a single storey skillion roof trusses. Any advice would be appreciated. Re: Slab heave/ slab design/ engineering questions..... 12Nov 16, 2021 2:40 pm Hi i may be bit late trying to help but your expert engineer is right,ive had the same but a lot more complex my slab actually spilt in 2 place we took it to vcat we knew we had the evidance we nedded unfortunately we got a lawyer that was in it for the money i thought boy was i wrong he was actually passing information onto the builder he was told to make our case go away, accoring to our files after we parted ways there was a lot charges but no proof from the barrister. Anyway our story is bit long but ill say this what ever a engineer disgns plans they have a hand shake with builder i can only speak for myself but if there's any indication looks like all volume builders do the same crap with slab heave there is no fix once your reo has been bent with heave there is no fix for it, piers are over used for the wrong reason, piers are great if you have large trees or had trees removed that piers will help that is to stop sourounding soil from shrinking affects so piers are just in place to hold ylur slab up. But if you have water getting into your soil or clay your soil will swell 3times that causes your slab heave to heave piers will not do anything unlessthey are tied into the top slab, so as it standsid take the word of your expert engineer if your not sure hire another expert engineer for a second opinion bare in mind more experts you have mofe confusing it gets for yourself trying to understand the legal side of things, our lawyer is a ex builder turned lawyer what he did for us in 9 months our first lawyer connot achive in 5 years. And his rates are not to bad. If you need a lawyer that is honest and truthfull, his name is Mark Croft legal 1300366119 call him ask himthe question you need to ask. Let me know the outcome good luck Re: Slab heave/ slab design/ engineering questions..... 13Nov 16, 2021 9:43 pm What was your VCAT outcome? Did builder fix anything? Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Slab heave/ slab design/ engineering questions..... 14Nov 16, 2021 10:42 pm Underpinning done and Agricultural pipe installed 800mm deep in to clay around the house, just waiting on the engineers report that we had done 12 on the after the works he did new floor levels, i know that underpinning part of the house it's going to allow the rest of the house to move they said it will work so I know the slab is still moving according to floor levels I've doing this long enough to understand to read floor level now. Soon as i get the report should this week or early next week I know what the answer will be he will not sign off on it since he was not the original engineer . I will give builder 2 choices and only 2 that is bulldoze and rebuild or buy us out at market value. Will see out come of report. Assuming you've modelled the TB8, TB10, TB12, TB2 & J1 joists/LVLs there, it appears as per drawing to me. There maybe should be an additional J1 between TB10 and T12 if… 3 32299 Thanks for all replies. I just noticed now the pictures I added to post right on top of page were wrong. I attached pictures showing "current" and my "suggested" floor… 9 14969 Although I am a big opponent of using waffle pod slabs over H2/P soils under any circumstances, in your case I would certainly opt in to keep piers under central… 1 2551 |