How much deflection in floorboards is too much for tiling

[Oliver T]

I have screwed down my floorboards in all places and feels really solid but ... right up against the front door where there doesn’t appear to be a joist so it dips maybe 3-4mm with my full weight on it. The next joist is 8 inches further into the hallway and no movement . Should I rip up the floorboard and rectify or will that small amount of deflection be ok Once I have large cement board on it? It is about 6 inches from the front door that bends very slightly then the rest is solid as a rock . I’m being overly cautious do I have a solid subfloor to tile on . TIA

 

[Ajax123]

3 to 4 mm will pop your tiles.

 

[Oliver T]

Understood! Floorboards coming up tomorrow . It’s only a small area but better to have a solid floor all over . Thankyou for letting me know . I’ve researched the whole thing a lot and know here does it say the difference between really really winky boards and a gentle squeak . I’ve removed squeaks but that corner by the door needs to be reinforced . 👍🏻