300 year old stair replacement

[Wranglatang]

Hello,

I have just moved into a 300 year old cottage. The bottom two steps of the staircase have dropped and I now want to replace them. I’ve taken them up and removed a lot of old wood and debris.

the floor below the stairs is just dirt. Has any got any suggestions as to how I best support these two new steps. I can’t really provide supports from the walls as they are uneven and don’t provide a lot of support.

I was thinking about laying a brick base (or even concrete pour & then building a wooden frame ontop of that.

 

[blup]

Is it a listed building in which case repairs may need planning approval. If not then either cast some new concrete steps or make up a wooden frame to take the weight of the treads/risers. In each case protect from damp.

Blup