First remove the tank
Install new flooring
Reinstall the tank

Yes all preparations for renewing floor joists need to be carried before renewal of joists inc water tanks, pipe work and electric cables.

Ideally 1st fix plumbing & electrics need to be done before new joists/insulation/flooring laid,
leaving a safe platform for the continuation of project.

Hi,you need to move the old pipework before the new floor joists go in,then the new pipes are fitted once new floor joists are in,building control will check everything then weyroc floor boards are fitted once he is happy with everything.

If your changing the heating system, you should consider combi boiler which will eradicate the water tank, regarding the pipe work, the joists to be put in would be a lot bigger so your Joiner would able to cut pipe work were necessary and your new joists should not touch the old ones as they should go into the steels you are putting in giving room to put necessary pipe work through thanks glenn

I would think it would be easier if you took out the existing water tank/pipes (where required) then fit the new floor joists then your plumber can come in to fit the new plumbing system.

This is dependent on the new joist and steel levels if you are above the existing 1st floor ceiling joists then the pipe works can be addressed later in the project, all new pipes runs can be installed around the structural steels and joists, remember “STRUCTURE DICTATES “

Remove the pipes leave the tank until your chippy breaks through and starts to install joists then it should be easier to get it down through the staircase well.

Definitely the plumber first. It may cost a bit extra so they can rig up something temporary to ensure you still have some hot water, but the loft will really need to be completely clear for the new joists to go in.

We would normally try and do as much structural work around the existing pipework before moving them. When ready we would drain down the system, remove the necessary pipework, then install / finish the structure then reinstate pipework within the new structure.
If the system is being changed we would do this before we start any works in the area and divert the pipework as necessary.
hope this helps

You can’t work around the plumbing and tank as the new joists will be much deeper than the existing. Strip this all out, fit the new joists and partial flooring then reinstate the plumbing.