I'm about to put some Hardibacker 500 boards up in my wetroom installation and after browsing the forums I'm still unsure as to how to apply these boards. So far its looking like the dot dab plasterboard solution is a defo no no. But then some people mention to dot & dab and screw fix.
I have three bags of plasterboard adhesive left so ideally would use this but again not sure as recommended to use tile adhesive.

If your better to use tile adhesive is any ok? Cement based? Ready mixed? Water proof? Will just any cheap adhesive be ok considering suppliers recommend a full cover to each board.

Also if you need to screw fix does anyone know what the best method is to screw to block. I installed my kitchen to some of these air bricks and they are like butter. Would I need to pre drill the holes and insert raw plugs?

Any help much appreciated on this as like other jobs I want to make sure I do it right the first time.

Ta

You will need to plug and screw the Hardi 500 boards. What tiles are you planning on fixing? Are you selecting the Hardi boards for their load bearing capacity or just to save the need to tank the shower cubicle?

Tiles arent massive by any means, 20x30cm. I'm boarding and tanking to be on the safe side as its the first time I've ever done this. As you probably can see..

Are the tiles ceramic

yes they are

What tanking are you planning to use, please?
If you are not using the Hardi boards for load bearing then why don't you go with one of these options:

1. D&D plasterboard, then tank, then tile (low cost option)
2. D&D Wedi or Marmox or Kerdi board then tile (no need for tanking)
3. Plug & screw Hardi boards, then tile (no need for tanking)

Personally, I prefer to try and solid fix boards so if your walls are flat and plumb then you could trowel the wall with cement based tile adhesive and stick either options 1 or 2.

I'd go for Captains first option, IMO

I was going to use the BAL WP1 tanking kit, seems like the popular option.

So I dont have to screw fix the boards? Just apply adhesive?

With standard plasterboard I have never added extra screw fixings but where you know fixings sink, rads etc are going add extra dabs of adhesive.

So when you use screws the plasterboard dos'nt get pulled in.

I've already bought the hardibacker. An extra £90 instead of using plasterboard which would crumble if it got wet seemed like a good decision to me. And piece of mind when my kids are stood next to them. Same goes for the tanking really. £60 dont seem alot to give it an extra layer of protection. I'm not sure if you can be over careful in these installs as I'd imagine trouble down the line could be a nightmare!

Ok to summarise my method here:

1) Pre drill holes in my block work and insert a decent raw plug for the thermite block.

2) Install the hardibacker500 along my block work up to 2m in height using cement based tile adhesive. Fully loaded over the entire board.

3) Screw fix all holes to secure the hardibacker into place.

4) Seal edges with waterproof silcone and waterproof tape.

5) Tank the area with BAL WP1 tanking kit.

6) Tile

Does this method seem reasonable / sensible?

Thanks