Insulation on Block and Beam Floor

22 Apr 2015
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United Kingdom
We are about to insulate a block and beam floor with 100mm celotex and then put 65mm screed on top of that. Bit worried that the block and beam floor is a bit uneven and that the insulation may move when laid on top of it ... and crack the screed. Am I worrying unnecessarily or do I need to make the block and beam floor more level before putting the insulation sheets down.... and if so how is this best achieved ? Thanks
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It's just uneven - the rain sits in puddles on it in the lower patches - so not level all over.
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just worried that the sheets of insulation may not lie flat - so may move especially when the screed is actually being put down on it.
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I meant with the rainwater! :)

Is it really up to 15mm? Stick a long level on it to check.

You can cut your insulation Union Jack style to allow it to fit better but depends on the undulations, don't forget the polythene sheet over the top of the insulation.

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