New loft space calculation... Insulation included?

[DmitriyL]

Hi,
Loft conversion allows 50 cubic meters expansion before planning permission is needed and it is said to be the new roof space. However, if this conversion requires thick wall insulation application then surely that in itself will eat up a lot of space? Can that be compensate by further expansion? Has anyone found this aspect clarified anywhere?

 

[freddiemercurystwin]

The volume allowance is the additional gross external volume created. The thickness of the insulation etc is irrelevant to the calculation.

You can't add more volume above the 50m³ limit later on. Otherwise you could periodically keep on adding loft conversions. unless you apply for Planning Permission that is.