The floor joists in a 12' X 12' ground floor room in a terrace house have failed because of wet rot.
The joists are built into the exterior walls and the rot in the joists extends about four feet into the room. The joists have failed ie snapped about two feet into the room and are rotten for some distance beyond that point. It is therefore not a simple case of 'cut and replace' of the ends of the joists but rather a complete replacement of the joists (and floor boards).
The building is about 100 years old and it seems to me that it would be very difficult to introduce a cost effective and efficient damp proof course into the party wall into which the joists are built.
Given the circumstances it seems the most effective approach would be to ensure first that the air bricks are clear and secondly replace the joists with tanalised timber.
Is this feasible? Are there any attendant health risks in this approach?
Wrapping ends of joists in roofing felt seems to be a 'jury rig' solution.
Are there any other cost effective solutions or approaches to the replacement of the joists?
In carrying out the remedial works the floor boards will need to be replaced. In this day and age do you replace with T&G or is that too expensive? Or would it be chipboard and if so what thickness and how would you spec it?
Any help, comments, or directions would be very much appreciated.