Browse Forums Flooring & Floor Covering 1 Mar 07, 2014 3:46 pm We've recently had our lovely, expensive 32MPA slab with aggregate "polished" with disastrous results! Our project manager asked a separate polishing sub-contractor for a "polished concrete" finish but what we have actually received is a grind and seal. No one explained to us that there was a difference between "true" polished and a grind and seal. That aside, the finish on their so-called grind and seal is appalling. We have a dark oxide base with bluestone aggregate and the slab has multiple cracks through it (which we were told can occur and it seems we have been unfortunate). Without asking us, the polisher has filled the cracks with light grey filler. It is as if he has run a great streaks of white paint (up to 3 metres in length) all over our dark concrete. They have failed to fill most of the holes and pocks in the surface - some are up to 10mm in width and 5mm in depth and they are EVERYWHERE. To make matters worse, they have left deep circular grind marks around the perimeter of the space. Now that we have seen the floor, we've insisted to the polisher (and the project manager) that we asked for a "polished concrete" surface and have offered to pay the difference in cost between the two finishes. The polisher, however, is asking us to pay for the $4000 we initially agreed upon, and then wants to charge us an additional $140sqm (his "true" polished concrete cost) to grind everything off and start again! My question then is - is what they have done so far even an acceptable result for a grind and seal? I am loathe to pay them $4000 for a sub-standard surface that they are just going to grind off. We would love some second opinions - photos of the work can be seen here: http://hindsight.net.au/photos/ Re: Polished concrete disaster 2Mar 07, 2014 4:08 pm What does your contract say the finish is? If its polishes concrete, then thats what you should get. I wouldn't pay an extra cent. Firstly though, get an independent inspection and present a written report to the project manager and tell them you want it rectified by whatever means necessary entirely at their cost. Re: Polished concrete disaster 3Mar 28, 2014 11:18 pm Hi I am no builder or tradie, but that looks like a terrible job. I would seek advice from another polisher and get them to write a report. It should be the builders problem, not yours. With our builder we had to fill out the builders complaint form and send it to them to get anything done. They get nervous when you say you are going to the building commission. You must be heart broken. Re: Polished concrete disaster 4Mar 29, 2014 7:12 am It seems there are several issues here Firstly, the slab has excessive cracking, who supervised preparation and pour of concrete, are they experienced in exposed concrete construction? Secondly, there is no doubt grinding and filling is of poor workmanship, just look at grinding marks, it seems grinding machine just ripped out aggregate from the surface instead of grinding it. Was it ground too soon or was too much water added to surface at finishing? Neverhtheless I would have expected patching mix to be made from material ground off for colour match. Thirdly there is a fault in instruction set, why did you get grind and seal when you wanted polished concrete, What does your specification say?. What is your PM doing? There is no excuse for poor workmanship however best grinder cannot do a good job on a poorly laid base. It could be both. I was recently involved in County Court case where grinding contractor was blamed for poor finish. I demonstrated that instead it was owner's defectively laid base that was to blame, my evidence prevailed. http://www.buildingexpert.net.au/blog/b ... -in-court/ 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: Polished concrete disaster 5Mar 29, 2014 8:49 am I concur with building-expert. The finish not only depends upon the contractor but also the quality of the slab base as to the quality of the finished product. So you do have more than one issue here...What did the building company say about the slab beforehand ie did it pass tolerance inspection and did they say the cracks were hairline? You can't put a great finish on a poor base. But this job is also sub standard and not what you asked for. Re: Polished concrete disaster 6Mar 30, 2014 6:41 am As a commercial builder I have built tilt up factories from on site cast wall panels with 32MPA concrete. Surface finish is power floated to extremely dense and hard surface and 32MPA floor grinding should have given you a mirror finish without cracking. However, quality of finish starts with the designer,specification of materials, allowances for expansion joints, the right reinforcement in concrete in the right place, correct lapping, placement and coverage, then verification correct concrete strength and slump at delivery, avoidance of adding water on site (adding water on site may make workability easier but will weaken concrete increase shrinking and cracking), proper screeding and finishing and yes proper curing. (I have used spray on bond release agent straight after float finish). It's all about project control. That's why you need to ask about competency of your designer, concreter and PM before you even start looking at what the grinder has done. Quality starts at the beginning. 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: Polished concrete disaster 7Apr 16, 2014 7:42 pm First of all if you asked for a Polished Floor that is what you should have got , what i see in your images is no doubt a shocker and only worth 20-30 per sqm Most polished concrete works we carry out really depends on how much edging needs to be done , etc this can had 20% to the price but for a 3000 grit POLISHED concrete slab you would be looking $100-120 per meter day in day out , I work with many companies large and small on both sides of the Tasman and thats the professional rate . The good news is you can get it still looking pretty good, despite im sure the slab not being engineered for a polished floor hence the cracking . A good contractor will buzz of the crappy sealer and start again . He will have to do some crafty pit filling and GSM work but in the end you may lose some of the cracks Concrete will do what it wants and move and shrink what it does best Get a reputable company in .. can offer someone if you tell me where you are located and complain because even for a grind and seal that was POOR workmanship ... You should even give them a shout out and warn others J Re: Polished concrete disaster 8May 15, 2015 3:00 pm Not enough grinding, no grouting, no densifing and no polishing. Why were they there? Where you are coming from is where you are going to... Re: Polished concrete disaster 9Sep 18, 2021 5:18 am Hi Sarah, I have just gone through exactly the same thing and would love to hear how you went with this as I have a tribunal meeting in a few weeks. Its heart breaking that a huge part of your home looks like this.. sarah452 We've recently had our lovely, expensive 32MPA slab with aggregate "polished" with disastrous results! Our project manager asked a separate polishing sub-contractor for a "polished concrete" finish but what we have actually received is a grind and seal. No one explained to us that there was a difference between "true" polished and a grind and seal. That aside, the finish on their so-called grind and seal is appalling. We have a dark oxide base with bluestone aggregate and the slab has multiple cracks through it (which we were told can occur and it seems we have been unfortunate). Without asking us, the polisher has filled the cracks with light grey filler. It is as if he has run a great streaks of white paint (up to 3 metres in length) all over our dark concrete. They have failed to fill most of the holes and pocks in the surface - some are up to 10mm in width and 5mm in depth and they are EVERYWHERE. To make matters worse, they have left deep circular grind marks around the perimeter of the space. Now that we have seen the floor, we've insisted to the polisher (and the project manager) that we asked for a "polished concrete" surface and have offered to pay the difference in cost between the two finishes. The polisher, however, is asking us to pay for the $4000 we initially agreed upon, and then wants to charge us an additional $140sqm (his "true" polished concrete cost) to grind everything off and start again! My question then is - is what they have done so far even an acceptable result for a grind and seal? I am loathe to pay them $4000 for a sub-standard surface that they are just going to grind off. We would love some second opinions - photos of the work can be seen here: http://hindsight.net.au/photos/ To my understanding early saw cuts are to control shrinkage cracks, so doing them now would be pointless. Control joints may reduce ugly cracking during periods of soil… 3 9863 Hi all I need a guidance on how far I need to space expansion joints in the concrete driveway and its type (keyway/foam.) Contraction joints are at 3m max for a 125 slab. Thanks 0 10947 |