Loft insulation regulations

[blueharvester]

We have just moved into a new build (detached) and I've noticed that the insulation in the loft is only 4" thick. Is it not regulation to have at least 8" of insulation? If so then could I just put an extra layer down on top of the exising insulation? Would it be cheeky to ask the builder to provide us with an extra layer of insulation?

However, I am looking to floor the loft and if the new layer of insulation is an extra 4" above the joists then what do I attach the flooring to?

 

[Agile]

The loft insulation has to meet energy saving regulations NOT any particular thickneses.

Trad fibreglass has to be about 300 mm but if its a special with silver colour foil then it may have more insulation value with less thickness.

If in doubt then ask your local building department.

Tony