I have bought the Dunlop Waterproofing Kit for my shower area (and if some is left over I may put some over bath).

My shower area is Hardibacker board on a stud wall, with a built in recess for shower gel and the like. I have a couple of questions that I hope someone can guide me on?

1) Should I use the included primer with Hardibacker or is it not required with this substrate?

2) Should I tape the joints with fibre mesh tape and tile adhesive (as stated in the Hardibacker literature), then use the Dunlop tape to go over the joints again and then tank? Or is all that is needed is the tanking tape?

3) I will be fixing travertine. Do these tanking kits have weight restrictions?

Thanks,

Daz

to be honest I wouldnt tank the backerboards but I would tape and tank the corners

Originally Posted by mikethetile

to be honest I wouldnt tank the backerboards but I would tape and tank the corners

Why would you not tank the tile backer board? The boards are not water proof.

the boards wont break down when wet which is the main cause of failure in shower enclosures, the backer board is an ideal surface to tile too

Originally Posted by mikethetile

the boards wont break down when wet which is the main cause of failure in shower enclosures, the backer board is an ideal surface to tile too

Oh right! All the research I've been doing seems to suggest that these boards should be tanked as well to prevent moisture and water pentrating through the boards and into the stud walls. Is the tanking really not necessary?

I've weighed my tiles and they work out at 30.625 Kg per m2. I contacted Dunlop and they say that their tanking solution only supports a maximum of 32Kg per m2 (similar to BAL's WP1). This suggests that with adhesive and grout then my maximum total would be around 33.625Kg per m2. This is over their maximum. Have I now got the wrong tanking solution and what tanking solution does support this weight?

Anyone any guidance?

Thanks,

Daz

Hardie will still let water pass through even though it does not break down

i always tank backer board and aqua panel

modified cement faced boards only need joints sealed

Thanks but looking for an answer to the weight issue?

Sorry that came across a bit blunt.

I should have said that yeh I thought you should tank.

Any ideas about the weight issue? Perhaps I should revert back to the Homelux though they ignored two emails asking about weight restrictions. Though their literature has pictures of their matting with travertine over the top.

What do you guys think?

can't answer your question but bumped it up for

As far as I am aware systems such as dural wp membrane has the same weight limits as the substrate. Wetdec would be the one to ask I guess or Dural themself.

Originally Posted by Sir Ramic

As far as I am aware systems such as dural wp membrane has the same weight limits as the substrate. Wetdec would be the one to ask I guess or Dural themself.

Great thanks. Can anyone confirm the weight limits for the membrane type of tanking?

Thanks,

Daz

as its skimmed Hardie i would assume its the same weight limit as for plasterboard

why has the hardie been skimmed

Where does it says its skimmed ? I must be blind.

Nope it doesn't say skimmed. Why would I want to skim Hardibacker board?

Anyone any advice (factual and from experience if possible )

I think the problem is Daz, you are asking for an answer where there isnt one

im not bothered what others say, I now know you dont tank hardie with the tanking material you are using as it wont carry the weight of the tiles

what I suggest you do is change tack and use kerdi board as this will carry the weight of the porcelain tiles, it has a waterproof membrane built in so only the corners need taping

you cant expect materials to perform outside their design capabilities and need to look for materials that are suitable for the job in hand

Originally Posted by mikethetile

I think the problem is Daz, you are asking for an answer where there isnt one

im not bothered what others say, I now know you dont tank hardie with the tanking material you are using as it wont carry the weight of the tiles

what I suggest you do is change tack and use kerdi board as this will carry the weight of the porcelain tiles, it has a waterproof membrane built in so only the corners need taping

you cant expect materials to perform outside their design capabilities and need to look for materials that are suitable for the job in hand

Thanks for the advice.

The Dunlop kit would be slightly over their maximum weight guideline so I'll give up on that idea and take it back to Screwfix.

The Homelux membrane though may still be an option. I just can't seem to get confirmation of the weight limits. There is nothing in their literature and they don't reply to any emails. I would guess that it should be ok though because all the photos in their leaflet are examples of travertine tiles fixed to the Homelux.

Surely someone on here must have either used the Homelux membrane with travertine or used an equivalent matting?

Thanks,

Daz

theres no reason why homelux wont take the weight as you are bonding through the matting onto the substrate, hardie backer will take the weight its only the paint on tanking that was a weak point