Exending a solid floor by ~7cm

[luz624]

Hello, we have a solid floor (hardcore, sand blinding, concrete sub-slab - and will be adding insulation, UFH and 100mm polished concrete over). However, we need to 'extend' this area by a small amount -  about 7cm (w) x 70cm (l) - to account for where the doorways will be. The other side will be a bedroom suspended floor with carpet, with sliding doors on the bedroom side. We don't want the carpet to show when the sliding doors are closed, hence wanting to extend the polished concrete floor to this area. 

 

What is the best way to do this. Instead of hardcore/sand blinding/sub-slab in this very small area, can we lay bricks or concrete blocks in this area, next to the solid floor, and then just put the insulation/UFH over that, and then polished concrete over the whole area?