Bathroom Floor

[ah666]

Hi, I have read through various threads here, and I have successfully tiled a couple of bathroom floors however I am about to embark on a new bathroom floor and want to now the ideal method if I was to start from scratch, here is the current scenario

• The floorboards (chipboard) in our bedroom and ensuite bathroom creak whenever we walk around
• The bathroom and bedroom are an extension over a double garage
• I can feel some deflection when I jump up and down on the bathroom floor

Here’s what I am proposing to do :

• I am going to take up all floor boards in both bathroom and bedroom
• Install insulation in the void
• Install some extra timber alongside the joists to improve the rigidity (I have read this will help)
• Replace the floor in the bedroom with new chipboard

However when it comes to the bathroom as I want to tile and possibly lay underfloor heating (wet if possible) what is the best method ?
I assume I will have to try and improve rigidity as per the bedroom
In the previous two bathrooms I have done I have fixed Hardibacker over the top of the existing chipboard floor (didn’t have deflection issues and followed instructions on here)

But I now have clean sheet of paper, so do I

• fit chipboard and then hardibacker
• just use thicker hardibacker
• use ply and no hardibacker etc.

I don’t really want the bathroom floor to be significantly higher than the bedroom floor so does this rule out underfloor heating ? (as I assume this would go between the floorboards and tiles and not below the floor boards, a novice when it comes to underfloor heating, will get someone in to do it if I go wet, but like to know what I am talking about)

Your thoughts and suggestions gratefully appreciated