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Posted: Fri Jul 02, 2010 11:55 pm
by prits_uk2002
hi this is my first post and the first time i have laid or should i say tried to lay slabs. the situation is i need to put a shed up and the area i have chosen was full of mud. so i levelled the ground made a frame put 10 cm of hardcore wacker plated it down put 1cm sharp sand used a long peice of wood cut out the depth and ran it along the frame to get a flat surface. i then put 2cm of slab base which is made by hanson. i followed the same process of levelling the sand on the slab base which is a dry mix no need to add water its supposed to cure over time. laid slabs using 1cm spacing lightly tapped them down with a mallet. the next day removed spacings and filled the gaps between the slabs with the slab base as well. i have waited 5 days and thought i will check if the slab base is hardnned i touched the gaps between the slab and it wasnt hard. i walked over the area and it wernt set under the slab either as when i steped on corners of slabs they tried to lift on op side. where have i gone wrong? i thought the slab base being a dry mix would have been good. i called tech team they advise its a mix of sand and lime or lime stone or something along thoose lines. the product does state hardens over time but surly in those 5 days at least it should have supported my weight and not rocked the slabs when i walked on them.
Posted: Sat Jul 03, 2010 7:37 am
by Mikey_C
i presuming amongst the list of ingredients in hanson slab mix is cement. this needs to react with water/moisture to "go off" due to the rather unusually hot weather lately i imagine your hardcore, sand, slabs and the ground they were in are all fairly dry. yesterdays rain (if you had any) will probably help, but you could try watering it gently on top and around and leave it a bit longer.
Posted: Sat Jul 03, 2010 9:48 am
by prits_uk2002
thanks i dont know if it has cement in i think it uses lime instead as they didnt mention cement which i thought was odd. what i was thinking was the slabs i laid i did want them sitting 2cm higher so they sat proud of the framework cud i get sand and cment 6/1 or even 5/1 sand cement and add in on top of slab base or should i remove slab base and then do sand and cement. im not sure if the lime and sand and the cement would have any reactionproblems?
Posted: Sat Jul 03, 2010 1:17 pm
by mickg
i sounds like you need to start again if the flags are rocking after 5 days, lime does take a lot longer to cure than cement and especially if its not rained, plus its on top of hardcore so the mixture can't draw any moisture out of the ground hence it just can't cure
remove all of the slab base and either on a plywood sheet or using a wheel barrow add a little bit of water and cement to the mix and relay all of the flags and it should be hard the morning after
Posted: Sat Jul 03, 2010 11:40 pm
by prits_uk2002
thanks. so just to confirm remove the slab base and mix the slab base with cement and add a liitle water then relay it. or do you mean remove slab base and throw it away and just use sand, cement with a little water. just dont want to get it wrong again.