New flooring upstairs

[changerlot712]

I'm hoping for some rough ideas on costs.
Viewed a house that has a lot of potential, but I'm pretty sure the entire upstairs flooring needs to be replaced. Perhaps the joists too. There were multiple holes in the floorboards and the rest of the flooring felt weak.
I'm assuming it would be hard to estimate when not knowing if it's rot, woodwork or just age...
I'm guessing this will run into the 10s of thousands?
Anyone with any knowledge on this?

Well I will speculate.

Big difference between floorboards and joists. Floorboards I reckon fairly easy to take up and replace with new for a competent diy'er.

Joists, somehow get old ones out and new ones in. Hard to see how that will work but feels a lot more expensive than the boards.

If you can narrow down to boards or boards and joists that would probably reduce your risk window considerably.

Thanks. I'm just speculating about the joists needing to be replaced. Definitely new floorboards for entire upstairs.

I guess the problem is that you need to pull up the floorboards to get a good apprasial of the state of the joists. There is some stuff on YT about seeing whether the floor flexes, but I guess that can be caused both by bad floorboards and bad joists. Maybe the solution is to pull up the boards that look in the worst condition to see the state of the joist underneath.

If the joists need replacing then doesn't that mean new walls too because they are built on top of the joists/floorbaords?

This isn't my property - just one I have viewed, so sadly not in a position to pull up floor boards.

I’d say it’s unusual for joist to go if it’s just floorboards that’s a relatively cheap fix you could put down sheets of chipboard