How to fit backer boards to walls 

Things have changed a bit since you posted this video but it's not just recommended to use backer board for wet areas such as showers but it's actually required by BBS along with tanking of the area ( or waterproofing ). A few things in the video are a bit off the mark. Cement board is not hydrophobic and it will absorb moisture if it's exposed to it. The difference is that it will not degrade to the same extent as gypsum based products and generally, it will take a rather long time for a leaky grout line to cause an issue. However, you must tank the surface if you want longevity and compliance with BBS. It's also not a hard thing to do now that you readily have liquid applied waterproofers and you are looking at a minor increase in cost. Even replacing a portion of the tiling because of a failure would cost you more than tanking the entire room and not just zones 0 & 1. edit: sorry for the corrections ... your wall is filled with insulation but the vapour barrier is missing. That's a mistake and you should have a vapour barrier on the warm side of the wall, i.e. the bathroom. I'm well aware that 90% of builds are not like this but we are not talking about barely passing standards here, are we :)

Can I use cement board on the wall behind my kitchen taps . Great video

Can I fit backer board to an existing plastered block wall, prior to fitting wall boards for a wet room? How best to fix the tile backer to the plaster?

I am keen to use this type of backer board for its ability to carry loads like grab rails but I'm concerned that cutting the large diameter (150mm) holes for the concealed shower valve etc is going to be tricky without creating a lot of dust etc. Can you please advise? Thanks.

Hello! How long after that would I be able to tile? And could I tile straight onto that?

How would I go about fitting backer board onto a plastered block wall in my bathroom?

Can the boards be fixed using plasterboard adhesive to brick or block walls!

arent you supposed to leave a 2mm gap between boards ?

Off topic - but what kind of insulation was that?

Don't need to fill the gaps mate