Repairing/replacing subfloor who to contact?

[Feelings]

I need to get some quotes for subfloor replacement in both reception rooms.
They're currently suspended timber but looking to possibly replace with insulated concrete depending what the expert suggests.

Can someone tell me who I would need to contact for this type of job?
I'm not keen on getting a timber specialist in as I've read they're cowboys.
Although I do need it checking for rot etc it's definitely damp under there!

Anybody??

What’s making you think you need to replace it?

Surveyor has said there's mould growth on a new plank and advised to investigate. I'm thinking worst case scenario at the moment and just wanting to know who I would contact for this type of thing.

The house is also Victorian.

You might just need to clear out the sub floor area, check the joists are on slate and install some extra airbricks to improve the airflow.

We had this on our joists in the loft, but advice was just to be more careful with moisture levels in the house, ventilating after showers and when drying washing etc. Mound growing is a long way from rotten so you may well be fine.
That doesn’t help on who to get advice from though, sorry.

Yeah we've been told to install extra air bricks so I think we'll take a look first and decide from there.

He just said that repair could be costly and disruptive but he isn't sure what the cause is.