I'm about to start overhauling our bathroom walls. One wall I plan to remove the tiles (which are roughly waist high) and then replace the tiles with tongue and groove. The house is old and walls are largely plaster and lathe so I'm guessing I'll take most of the plaster off when I remove the tiles. My plan is to just take the plaster off and replace it with plasterboard then put the tongue and groove over the top. I'd also like to put some insulation behind the plasterboard just to keep the heat in a bit better. Does anyone have any ideas what I could use?