Can anyone advise the correct method to lay reinforcing mesh in a 600mm wide foundation. The builder I have has just chucked a few bricks in the base of the found and laid the mesh on top. I read somewhere that this is not acceptable and there are proper fixings/supports for this purpose. Any one know what the correct term for these supports?
You are certainly right to query this. You can get proper spacers and stands for steel reinforcement. The issue with laying reinforcement on a few bricks is that the steelwork will have inadequate concrete cover. This is likely to result in premature corrosion of the steelwork. As reinforcement has been specified for your foundations, talk to the engineer that specified the steel sizes, he will be able to provide job specific advice on this isse.
Thanks for your reply. I made enquiries to the local builder merchamts on this one and he said that he did stock at one time ceramic stools to support steel mesh in foundations but no one uses them now , Quote " they just chuck a few bricks in the base, this is now normal practice" . The builder I had has now delegated someone else to sort out his major faux pas and these new people seem to have a better idea of whats required. They will be using C35 grade pre-mixed concrete which has fibres mixed through it and apparantly does not require steel mesh in the pour. The last guy did not know about C35 so I am keeping my fingers crossed that all goes well, they are knocking down the last guys blockwork and digging up the base as I write.
Sound like your better off without him. A builder not knowing about C35 mix concrete is a bit like a chef not knowing how to make a bsic white sauce. C35 is the strength class of the concrete. (the crushing strength). They will only be able to buy it mixed accurately via ready mix. The fibres are a relatively new intruduction to concrete and can massively improve strength.
Latest news is that the original builder and his subbies have been called off the project and a new builder arrived today with the conservatory rep to take stock. This new company is a family firm ,been in business since 1982, all qualified tradesmen and so on. I must admit I was pleased when the first lot were taken off the project as they were just not in the frame. To the original question regarding mesh in the foundations, I asked this question to the new builder today and he says they always pour in 50mm concrete first, lay the mesh and then continue the pour to the required depth which seems reasonable to me rather than the " bricks in the base " concept. This new company do around 150 conservatory bases a year for the main company so they seem to have a good track record. I have checked their web site and they seem proficient enough. They will be on site on Thursday to continue the removal of the faulty base and then excavate to required depth and then start the re-build.
Thanks for your interest Pedro.