Building cover for underfloor pipes for tiling

[Matt&g]

Am planning to take up the floor in the entry way to be able to install some new radiator pipes into a storage space to help with some damp.
There is the 2 radiator water pipes and a gas mains pipe that runs thru a chased out void under the floor boards currently.
I want to replace the boards with tiles just as i cant seem to find replacement boards and doubt i can make it all blend nicely.

The problem i'm facing is how to build a removable lid that the tiles can sit on top of so that if i wanted to access the pipes at a future time it would be possible?
Tho it also needs to be strong enough to stand on..

My other thought was to use some tile backing board to cover the void and the area i want to tile to bring it up to height and then tile over the top but unsure if the backing board will be strong enough when its floating over a void?

Any ideas on how to either permanently cover the pipe or build a removable cover would be great

 

[oldbutnotdead]

Tiles need a solid supporting substrate. Any flex and they'll crack.
Floorboards- are they actual solid boards or is it some sort of laminate? If they're solid boards go to a timber merchant (NOT a DIY shed), they'll be able to sort something out.

 

[Matt&g]

Yeah was worried and flex would be a problem thinking maybe will need to use a piece of metal plate with some 10mm or so backing board to be sure nothing moves or even a solid cement screed