What size battens for plasterboards

[iamlee2002]

Hi all currently sorting my upstairs out, chiselling all the awful mortar which is 2 inches thick lol. I plan to batten the walls and screw plasterboards to them. What size timber is recommended ? Was thinking of using 2x2 as I previously done in my bathroom. Is that the normal size to use? Would you also put a polythene vapour barrier up prior to battening or no polythene ? Any advice would be greatly appreciated many thanks. Lee

Edit : please note my walls are the old solid stone just short of meter thick

 

[ree]

Given that you have stone walls then "the 2" thick awful mortar" was probably applied as a remedial measure
- typically, use a sand and lime mix on stone do not use any gypsum plasters.

Research similar topics on here, there's masses of it.