Hi all, just a quick question for those with some knowledge in regards to installing 6mm cement tile underlay on top of particle board / t&g.

Our tiler starts next week and we are doing the underlay ourselves. We are nailing the sheets and also putting a bit of liquid nails under each piece, and staggering them as per the instruction guide by JH. The tiles we are using are 1200x200 rectified tiles, so the grout lines will be minimal.

Our tiler however has said that we don't need to bother with expansion joints - this seems contradictory to most underlay manufacturers guides.

Any thoughts please?