Difference between WediBoard & 'Tanking' for wetrooms?

Hi,

I've been reading earlier threads about creating wetrooms.

I realise this section deals with wall titling, but I think it's relevant because it's the tiling I'm trying to make watertight.

From what I can gather, to create a wetroom you (correct me):

1) Lay marine ply (in place of existing chipboard floors).
2) Tank the floor and walls with special tape & sealing compounds.
3) Add tile adhesive and then the tiles & grout.

I know you also need the special sloping tray that slots up next to the floor boards and is level with the floor boards so you get an even tile surface but.......

where does wedi tilebacker fit into all this?

From their website it appears that you need the wooden floor AND then their wedi board (which adds much more thickness than tanking compounds). I assume you do not then need the tanking kit as the wediboard is waterproof.

Why would you want to pay for the expensive wediboard (and have to cope with the increased thickness - means notching out the joists to keep the floor level) over a tanking kit?

I assume wediboard is better in some way?

Thanks.

I'm starting a wetroom project and using wediboards on the walls with a Schluter tilebacker membrane on the wbp ply (no need for marine ply, too costly)

The wediboard for the floor is a good option. You can get it in 10mm, so the increase in height is minimal. It provides a very stable base for tiling when screwed to the ply.

The other benefit is the insulation value of the wedi- useful if you are having underfloor heating.

Wedi is really nice to work with, strong, easy to cut, clean (no messy liquids)

Downside seems to be price.

I'm beginning to see that the wediboard has a structural element to it which is used to further improve the longevity of the edge seals. With tanking, the amount of movement is completely dependent on the board you're tanking.

I've spoken to some bathroom fitters today who deal with wetrooms, and from what I can gather, it's 6 of one and half a dozen of the other. Wediboard is used 'instead' of plasterboard where high pressure jets are likely to force water through the grouting (power showers etc). Wediboard does not (so they claim) rot in the same way as plasterboard once it gets wet. You can get Wediboard in the same thicknesses as plasterboard too so all your tiling lines up.

Wediboard also seems well suited to making odd shaped shower trays. You just cut it up and then glue / tape it all together in the shape you want, ready for tiling.

I'll be using a mixture of wediboard and tanking in my bathrooms. I can't notch out the joists because of they way they lock together, so I'll use tankig by the door so the floor is level with the carpet outside, and wediboard further into the bathroom area where the shower is.

An alternative on the floors is Marmox boards. They do a 6mm board which means minimal height gain, but give the insulation properties for UFH. It is virtually the same as Wedi, being expanded foam with a fibreglass mesh/ cement screed either side.