New floorboards or concrete?

[Jono_UK]

I have just bought a 1930's semi. The ground floor has kitchen, hall, under stairs cupboard and toilet all with concrete floor and front room with wooden joists and floor boards.

After lifting the front room floor boards I discovered a number of rotten wooden joists. (I expected this and it is no big shock). My neighbour said that the soil floor under his front room (60cm void between joists and soil) often has water in it due to low water level.

Now, I will be putting an extension on the rear of the property with a new concrete floor I am going to dig up the remaining concrete floors replacing with dpm, insulation and new concrete/screed etc.

My question is, should I
A)Replace the rotten wooden joists with new wooden ones and put new floor boards down - fixing any loose bricks and ensuring vents are nice and clean and good ventilation under floor.
or
B)Take out all wood and at the same time as replacing the remaining rooms floor with concrete, include the front room too?

 

[Nige F]

Option B........cuz the rots caused by lack of ventilation....the existing solid floors stop any flow of air under solitary wooden one

 

[Jono_UK]

Option B........cuz the rots caused by lack of ventilation....the existing solid floors stop any flow of air under solitary wooden one

Does anyone know of a good web site that can indicate how to put in a slab, dpm, insulation, screed etc in a house already built without continuing dpm into dpc in wall?

Thanks
Jono.