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Q&As
Raft Slab Resolution
Our groundworker has built our reinforced rebar raft slab to the correct depth but it is not level and is at the wrong elevation for the remainder of the build. In places is is between 20 and 50mm too low. What is the best way to resolve this? The groundworker says a self levelling screed could be applied but I am unsure whether this will prove structurally sound to take the weight of the ICF (ISOTEX) walls and 3 storeys.
One Answer
I am afraid you need to consult the structural Engineer who designed the raft. The raft is designed to take wall and roof loads and so you should not apply any products which could become load bearing without fresh calculations to support the design. If its only a question of making up floor levels for your finished floors then screeds can be useful. However, 20-50mm is a sizeable depth. If it was me, I’d have a full survey of the slab carried out by the engineer and their remedial recommendations implemented. The cost of this exercise should be picked up by your contractor.