Category 2 – paragraph 2.21: Is a step up into an inset balcony or roof terrace permissible when this is located above accommodation that needs to include insulation?

Yes, for Category 2 where there is a need to insulate inhabited areas below a balcony or terrace a step-up of up to 225mm would be reasonable. This does not apply to Category 3.

Category: Part M - Access to and use of buildings