We're planning an extension to our house, a full width kitchen extension with full knock through (and a central column due to the 7m span). The existing concrete slab in the house is knackered. It is concrete, screed, then magnesite. But it is badly cracked and uneven, possibly sulphate attack. The fridge is currently stood with one leg fully extended AND on a strip of wood to level it. The old fireplace hearth is about 20mm higher than the floor but was originally level!
In the living room and hall (less badly affected), I chipped off the high points of magnesite and filled with flexible self levelling. Probably not the right way to deal with it but those rooms are carpeted and you dont notice the unevenness now. Additionally, all the houses round here have this same issue but not heard of any having a floor slab replaced.
Anyway, in the kitchen, we want a tiled floor so the current slab in there has to go. The current kitchen is about 3m x 7m (yes those dimensions are right, its a wide house). The combined space will be 5m x 7m. Rather than laying two slabs would a builder remove the old external wall the same depth as the rest of the floor and lay one big slab? Would a movement joint be put in in case the extension settles? Or would this not be necessary?
In the living room and hall (less badly affected), I chipped off the high points of magnesite and filled with flexible self levelling. Probably not the right way to deal with it but those rooms are carpeted and you dont notice the unevenness now. Additionally, all the houses round here have this same issue but not heard of any having a floor slab replaced.
Anyway, in the kitchen, we want a tiled floor so the current slab in there has to go. The current kitchen is about 3m x 7m (yes those dimensions are right, its a wide house). The combined space will be 5m x 7m. Rather than laying two slabs would a builder remove the old external wall the same depth as the rest of the floor and lay one big slab? Would a movement joint be put in in case the extension settles? Or would this not be necessary?
