Bathroom re-fit......question about the wooden floor prep

[Ula NI]

Hi there.
Some advice please, we are having our bathroom and en-suite refitted and the guys who are completing the work have stripped out the rooms.
My question is, i'm not sure that they have any intentions of removing the ply-board in the pictures which to my untrained eye looks rotten - the previous bathrooms had leaks.

Will it be fine if left or should it definitely be removed?

A quick response would be appreciated as i think the plumber is returning tomorrow as part of their outfit) and i need to know if i should object with them carrying on or demand to have the wood replaced?

Thanks

 

[vinn]

Yes, all the suspicious floor boards, or sections of the boards, should be replaced or at least sprayed with anti-fungal chemicals., and the area & any new material treated with anti-fungal chemicals.
The damp appears to have gone below the sheet mosaic.

The ply will create difficulties - maybe using a reciprocating saw will remove and rough up the first few surface mm's of the water darkened areas, then they could be treated with chemicals.
Using ply as a tile backing is bad practice. Presumably the ply is screwed to stud walls?
Check the far side of all the walls.

Cutting massive openings for a shower waste is also bad practice.
Dropping in the shower base, and connecting the shower drain to that waste stub (is it trapped?) might prove difficult.

 

[Ula NI]

Vinn thanks for replying.
If you don't put ply on a stud wall what should be used?

 

[vinn]

For wet walls you can use backer board.

 

[Ula NI]

Thanks Vinn, the ply was removed and the wooden framed studwork is rotten, waiting to see if the floor joists are ok or not, bit bigger work than we thought, be at least now we know.