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[Mikkir]

Hi
We have blocked up our external kitchen door and are now selling the house and need a late completion certificate but the council are being a nightmare. We have submitted a diagram showing we done 100mm concrete block with a 50mm clear cavity and 50mm insulation then 100mm concrete block. He now needs to know the type of insulation used and the thickness (he said the 50mm cavity and 50mm insulation isn't correct) it is standard construction wall. Can anybody tell me what should have been done and what insulation should be used?

[welsh brickie]

By your description, you have a wall thickness of 300mm plus plaster thickness, If this is a modern house then that would be the case, but I suspect it is not. Your cavity should be between 50 and 75mm wide, you can either full fill cavity with rockwool cavity batts or 25 to 50mm thick celotex cavity batts