What type of tradesmen to repair joist/lay DPM?

[spursfan323]

I need a rotten joist spanning my upstairs hallway (and some creaky soggy floorboards) to be replaced.

I also need someone to lift my extension suspended wood floor and check if a DPM exists (don't ask, cowboy builders) and if not, to fit it.

What type of tradesmen do I seek?
I'm reluctant to take a contractor and suffer his inflated price if I can get the tradesmen direct. Any advice?

Thanks

 

[ree]

Why do you have upstairs fungal decay issues, what is the cause?

As usual pics will significantly help.

A local joiner (especially one with D&T remedial experience) could do both jobs but presumably you first need to know what is going on upstairs?

Beyond checking below the extn flooring for an oversite membrane, are there any other issues that have drawn your attention to the floor?
Why this question - why now?