Ground floor joists only supported on dwarf walls.

[olly100]

I've just bought a semi detached house built in approximately 1900. A couple of floor joists on the ground flor are a bit rotten due to leaky plumbing, and possibly need replacing. on further investigation it appears that the joists do not make contact with the external walls at all, and are supported on a series of dwarf walls about 1m apart. Is this normal?

What is the best way to replace the rotten sections of joist.

 

[^woody^]

Yes that is the correct way - the timber is kept off the main walls and less prone to getting damp from the walls. Didn't work in your case though!

Easiest thing to do is to place a new joist next to the old ones. Make sure that the rot is treated and stabilsed though, that ventilation to the floor void is sufficient, and that there is a DPC between any timber and brickwork