items required for overlay boards and tiles

[Ahmiccc]

Hi All,

 

hope your able to help think its a pretty simple question but just want to clarify everything ill need.

 

So the story is finish upstairs bedrooms ufh in-between joists spreader plates all good working which is great now moving to downstairs and its going to be a little bit different construction so its still joists which I've fitted with 150mm PIR and left a maximum of 2cm airgap before i fit chipboard which is where my first question lies.

 

So i was planning on running a 22mm chip board and overlay boards and then self levelling and then potentially having tiles but probably engineers wooden floor, but after a bit of research i found to stick the overlay boards down and this best goes on plywood or cement board and this helps to tie everything in so its solid especially since potentially could have tiles on top? so here comes the question i like to be super secure but of course i have a bit of restraints when it comes to door heights. so am i best to just go with the 22mm chipboard or 18mm chipboard and 6mm cement board on top and run the overlay boards 20mm with 150mm pipe centres then self levelling screed

 

Next question what's best pipe to use on the overlay boards ? am i okay to use the PEX-Al-PEX like upstairs ? will it bend to 150mm pipe centres ? or is there another pipe that's better for this application ?

 

Secondly what's the best self levelling screed to go on top of the overlay boards ? 

 

Look forward to hearing your opinion and suggestions I'm sure there will be more questions on from this but would be good to see what you all think

[HughF]

Why not just use pre-routed chipboard floorboards?

 

And yes, standard alpex is fine at 150mm.

 

Use Whatever self leveller you can get cheap.

[Ahmiccc]

cost and for somewhat more insulation i guess.