gravelrash Posted November 26, 2021 Share Posted November 26, 2021 Just had concrete finished floor slab laid yesterday which was power floated...How flat and level is flat and level? rained this morning before I had a look and there is a lot of ponding and high spots. Link to comment Share on other sites More sharing options...
Moonshine Posted November 26, 2021 Share Posted November 26, 2021 looks good to me, you are probably only looking at +_mm Link to comment Share on other sites More sharing options...
markc Posted November 26, 2021 Share Posted November 26, 2021 Water will look like puddles on the flattest of surfaces. This looks pretty good. Unless there is a deep bit in the larger area then I would be very happy with this Link to comment Share on other sites More sharing options...
Dave Jones Posted November 26, 2021 Share Posted November 26, 2021 not like you wanted it laid to a fall ...... Link to comment Share on other sites More sharing options...
Russell griffiths Posted November 26, 2021 Share Posted November 26, 2021 Will probably look different when it’s broken up with internal walls. Link to comment Share on other sites More sharing options...
Mr Punter Posted November 26, 2021 Share Posted November 26, 2021 Yet another inner city infill! Get a 5p piece and lay it flat in the centre of the puddle. If it is not submerged you know it is less than +-2mm. Link to comment Share on other sites More sharing options...
Bramco Posted November 26, 2021 Share Posted November 26, 2021 That's a small shower recess at the back! Nice view though. Simon Link to comment Share on other sites More sharing options...
gravelrash Posted November 26, 2021 Author Share Posted November 26, 2021 One of the best views in the area... only trouble is the 35miles of open view to Saddleworth and Derbyshire peaks which the wind loves. The shower recess is 2m x 1m Link to comment Share on other sites More sharing options...
Moonshine Posted November 26, 2021 Share Posted November 26, 2021 Lovely, well done on getting a spot like that. Link to comment Share on other sites More sharing options...
Gus Potter Posted November 26, 2021 Share Posted November 26, 2021 How deep are the puddles & how much higher are the high spots compared with the water surface. For all. If you can when your SE is designing any concrete slab or an IFC basement ask them to indicate on the drawings the level and flatness tolerances of say the hard core under the slab relative to a datum. Next maximum and minimum slab thickness relative to the datum. This is important as it can impact on what is going above.. say maximum and minimum thickness of wall plate bedding, slab performance and so on. Some times your Architect will also specify a flatness and level for a slab based on the floor finish requirements. It's good practice to do this. There is a difference between slab level and slab flatness. For example take a rectangular slab. One long end could be sitting 15mm above the other. The slab is sloping from one end to the other. It could be perfectly flat in between but if say it had depressions or high spots in it pretty quickly you can see that if you add the figures together then you invite problems with the super structure and flor finishes. It takes a bit of work to get your head around how you spec these things. A lot of SEs will use the BRE TR34 guide which relates to industrial floor design but it's easy to adapt for the self build market. On the other it is important not to go over the score and try and get things any flatter than the need to be.. you will just waste money. 1 Link to comment Share on other sites More sharing options...
gravelrash Posted November 27, 2021 Author Share Posted November 27, 2021 SE and architect never specified tolerance, the concrete guys had a datum to work to and guy floating the finish asked what floor finish I was having which I told him to just cover me for every type and get it as flat and level as possible. A rough check seems to be that the level falls about 8mm across 14.6m of floor with the puddled areas less than 2mm low and one spot has a slight ridge of 3/4mm and about 1m long...but I think this would be under a kitchen cupboard later. Link to comment Share on other sites More sharing options...
Russell griffiths Posted November 27, 2021 Share Posted November 27, 2021 12mm start to worry. I put a frame up on a slab that was 25mm out over 6m was a pain, but once up and tiled you could never tell. Link to comment Share on other sites More sharing options...
Thorfun Posted November 27, 2021 Share Posted November 27, 2021 15 hours ago, Gus Potter said: For all. If you can when your SE is designing any concrete slab or an IFC basement ask them to indicate on the drawings the level and flatness tolerances of say the hard core under the slab relative to a datum. Next maximum and minimum slab thickness relative to the datum. This is important as it can impact on what is going above.. say maximum and minimum thickness of wall plate bedding, slab performance and so on. and then the groundworkers come along and ignore it all. ? Link to comment Share on other sites More sharing options...
Mr Punter Posted November 27, 2021 Share Posted November 27, 2021 What you have there is well within tolerances. If you laid some Astroturf you could use it as a bowling green. I assume the puddles were not deep enough to cover a 5p piece? Link to comment Share on other sites More sharing options...
saveasteading Posted November 27, 2021 Share Posted November 27, 2021 I think that will be fine. An inspiring boss once dealt with this by chucking a pound coin into the puddle, and asking the client if he was now ok with it. He later explained that the water was deeper than the coin but that this always works up to 3mm, which is the tolerance. Remember that the slab will be a bit high and a bit low variously so this can exaggerate the effect. You will not notice this in real life and does not need an overscreed, If you ever see a leak in the fanciest of retail sheds, you will see just the same. The official test is a 3m long straight-edge (or an unusually straight piece of wood). Lay it anywhere and look for a 3mm or more gap. I suspect you will not have that. The water is good for your concrete anyway. Link to comment Share on other sites More sharing options...
saveasteading Posted November 27, 2021 Share Posted November 27, 2021 5 minutes ago, Mr Punter said: you could use it as a bowling green. Yes but the balls would be influenced. I did an indoor bowling centre once with 4 lanes. the concrete was in tolerance but did veer off at one corner by a few mm. This became home advantage. Once the concrete is dry, roll a golf ball and see how it swerves. Link to comment Share on other sites More sharing options...
gravelrash Posted November 27, 2021 Author Share Posted November 27, 2021 2'' slush on it today and melt completely filled the unfilled outside of footings trench...they had been left open for drainage later next week (brickie/ builders idea). Shit happens, just always happens to me!. luckily had an old vortex pump in the container to pump it out. Link to comment Share on other sites More sharing options...
markc Posted November 27, 2021 Share Posted November 27, 2021 (edited) 56 minutes ago, gravelrash said: 2'' slush on it today and melt completely filled the unfilled outside of footings trench...they had been left open for drainage later next week (brickie/ builders idea). Shit happens, just always happens to me!. luckily had an old vortex pump in the container to pump it out. ??? Are you trying to find problems that don’t exist? you are at slab pouring stage and appear to have a good job done so far, as the build progresses there will be problems and hiccups, save the stress and fretting for those. Edited November 27, 2021 by markc Link to comment Share on other sites More sharing options...
markc Posted November 27, 2021 Share Posted November 27, 2021 1 hour ago, markc said: ??? Are you trying to find problems that don’t exist? you are at slab pouring stage and appear to have a good job done so far, as the build progresses there will be problems and hiccups, save the stress and fretting for those. Sorry that was a bit harsh, it’s your build and you are wanting it right, but try not to find fault with everything or you will get more and more stressed as the build goes on. Link to comment Share on other sites More sharing options...
Thorfun Posted November 27, 2021 Share Posted November 27, 2021 1 minute ago, markc said: Sorry that was a bit harsh, it’s your build and you are wanting it right, but try not to find fault with everything or you will get more and more stressed as the build goes on. these are wise words. at the start I wanted everything perfect like it was on the drawings. it didn't take long to realise that reality is completely different to CAD drawings and building is just not a precise science. our Groundworker summed it up when he said 'building is basically a bodge'. by that he means that things will go wrong and so you find a solution to get over that and so on. then at the end of it all it's all covered up and forgotten about! 2 Link to comment Share on other sites More sharing options...
gravelrash Posted November 27, 2021 Author Share Posted November 27, 2021 Im not unhappy with the slab although I just assumed standard practice tolerances were tighter. I was an engineer and found 2 previous building conversions difficult...having to throw tape and level and rely on eye. Now Knackered with heart failure I decided to leave it to a builder and just organise materials for my final resting place. Link to comment Share on other sites More sharing options...
Gus Potter Posted November 28, 2021 Share Posted November 28, 2021 (edited) 14 hours ago, Thorfun said: and then the groundworkers come along and ignore it all. ? Can happen Edited November 28, 2021 by Gus Potter wrong thread Link to comment Share on other sites More sharing options...
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