Correct way to repair and replace T&G floorboard

[Mr Sparkle]

What's the best belt and braces method for replacing tongue and groove floor board

I lifting a few boards for plumbing/electrical work in the bathroom.

Should you replace with

1. Square edge timber floorboard i.e. Not tongue and groove

https://www.wickes.co.uk/Wickes-Whitewood-PSE-Timber---18mm-x-119mm-x-2-4m/p/9000036455


Or

2. Buy 18mm structural ply.

3. Something else?

I plan to put some concrete board and tile the area

 

[sircerebus666]

Why you replacing ?

Cut through the tongue , lift the boards , do the plumbing/electrical work and refit the boards

Use screws to stop them squeaking too

 

[Mr Sparkle]

Why you replacing ?

Cut through the tongue , lift the boards , do the plumbing/electrical work and refit the boards

Use screws to stop them squeaking too

Some boards are damaged beyond repair

Also some of the boards do not fill me with confidence that they will stay firmly down with no movement

As the bathroom will be tiled, i worry that poor floor boards will lead to movement which could lead to cracks and floor tiles that come off later.

Also don't they usually advise to screw some wood (like 2 by 4) under the floorboard for extra firmness?

Or is this all OTT?

Also i

 

[dontbelieveawordofit]

piece it back together with some cls underneath where needed, 9 or 12mm ply over with screws every 5-6” and tile.

 

[sircerebus666]

Some boards are damaged beyond repair

Also some of the boards do not fill me with confidence that they will stay firmly down with no movement

As the bathroom will be tiled, i worry that poor floor boards will lead to movement which could lead to cracks and floor tiles that come off later.

Also don't they usually advise to screw some wood (like 2 by 4) under the floorboard for extra firmness?

Or is this all OTT?

Also i

I can't be the only one who wants to know what you were gonna say!

 

[pemills]

I've been following this thread for a while for my daughter to see if a solution was suggested on how to remove and reinsert a new sheet of flooring grade t&g into the hole where a damaged sheet had been removed and putting in a new sheet is all but impossible unless the t&g sections are removed, in my daughters situation the only way I can see it being done is to screw & glue extended pieces of CLS across the corners and along the sides to ensure that the sheet is supported along the whole length. My daughters builder is advocating the use of biscuits which I think is crazy. Does anyone have any other ideas or suggestions ?

 

[Why Not Indeed]

Supporting the edges from underneath where the tongue is broken is the only practical way to do this. This is fair enough when dealing with a traditional T&G plank, but an entire chipboard flooring sheet is a bit more of an undertaking. For this reason, it would make sense to remove as little as possible rather than the whole sheet.
I am not sure how biscuits would work, you'd need to slide the sheet in horizontally. If you can't slide it in horizontally then you'd need to leave the biscuits loose, and then there's no point in the biscuits any more, right?