wall prep / dry lining with Hardiebacker?

[newplumb]

Evening everybody

Would like some opinions on the best way to go with this one please. Just refurbishing friend's bathroom. Took the old bath out today which was chased into the wall round two sides, including the taps/shower end. The new bath will also need to be chased into the wall in the same way so there's space to fix the bath screen to the wall (otherwise I'm into the window reveal).

The problem I have is that the new bath (Bathstore bath with fixed height panel) is going to be several inches lower than the old one. Consequently, the existing chase is a couple of inches above where the top of the new bath will be (635mm vs 585mm). I should say that 'chase' is the wrong word really, as the walls are only plastered/rendered down to the level of the old bath.

Would it be possible to afix something like Hardiebacker board straight to the wall to make a flush finish? I imagine I'd need to cut back more of the plaster higher up, otherwise I'd be trying to fix a two inch slither of board to the wall. Also, the difference in depth is up to 30mm in places, so I would have to pack out with some thin timber in places. Or since one of the walls is an outside wall (the other is a party wall - brickwork exposed on both), would it be possible/better to afix some foil-backed plasterboard? (I'm going to tank the shower end with BAL WP1 anyway).

I guess I'm looking for options that avoid the need to get a plasterer in as I don't want to delay the tiling process if possible.

Opinions on the above and any other ideas would be gratefully appreciated. Thanks

Matt

[simon1]

plasterboard and plasterboard adhesive, quick and easy

[newplumb]

Thanks Simon. Two things:

1) Given that the plasterboard would only need to come down to the level of the top of the new bath (as the new bath also needs to be 'chased in') - which is about two inches below the current plaster/render level - how much of the plaster above would you cut away? i.e. how small a piece of plasterboard (heightwise) would you consider structurally stable?

2) Would foil-backed plasterboard be required for the external wall? If so, can you still dot-and-dab this?

Cheers

[whitebeam]

No you can't dot and dab foil backed plasterboard, when the adhesive is dry the board will fall away.

[newplumb]

Thanks Whitebeam, I suspected that might be the case. Any thoughts on the best way to proceed with the situation I describe above?

[whitebeam]

You would need about 10mm behind the board when it sit flush to the face of the plaster for the bonding compound, you could use some one coat plaster from wickes