Levelling hearth between rooms

[chameleon001]

Hi,

Just had a kitchen diner knock through done, so now have the hearths/ chimney breast foundations between the 2 suspended wood floors.

What would be the best way to level the floor. This area will have a washing machine actually so the solid foundation will be helpful.

Am I best filling with mortar/ concrete? Then a thin level of self levelling over the top to level of floorboards? Or should I rip out, replace with joists and board to match?

Cheers

 

[chameleon001]

Forgot photo

 

[bobasd]

dig out all the soil from the hearths to a depth of about 350m from FFL.
after diggin out post photos on here.
examine for wet rot all the joist tails sittin on or in the hearth fender walls.
you should slip dpc material under any wood sitting on brickwork.

dig out the top courses of bricks from the old dividing walls

final you will be best to joist and board across allthe voids - longest lengths of board possible.

is the c/breast in roomsabove totally removed or supported by steel lintel?