Two houses ago, the second catastrophic plastic plumbing push fitting failure (in our brand new build by Britain's favourite builder!) forced us into a hotel while the builder lifted the floor (chipboard) on the ground floor. I was allowed to take a peek and was shocked to see the way that the floor was insulated:
From below, obviously, first the concrete (apparently with plenty of polystyrene embedded). Then, on top, 2.5 cm fibre glass insulation (the one with a paper sheet on one side, presumably to hold it together). Then, ~50mm wooden battens (the ones with rubber strips underneath to compensate for the uneaven concrete), and then the chipboard flooring on top.
Now, the 50mm air gap between the insulation and the chipboard floor was very well ventilated, so what the heck the purpose of the insulation below was supposed to be was lost on me, in my view the floor should have been insulated the way we do in Scandinavia, with the insulation material in direct contact with the flooring, and with the air space
*below*. Anyway the site manager told me that this was the standard way they insulate the ground floor so I just shook my head and let them get on with it.So now I'm in a third-floor flat by another builder, built around 2000, and lo and behold what do I see when I cut open the chipboard floor to move a radiator, exactly the same way of putting down the insulation. No wonder the bloody floor is cold on your feet in the winter, through the hole I can feel the draught and the insulation below the air gap would be completely useless!
So, what possesses at least two British builders to lay floor insulation in a way that is totally ineffective? Is this really according to Building Standards?