tanking - why?! - TilersForums.co.uk | Tile Forums

25-04-2008

hi, can anyone explain to me what is the point of tanking?
assuming you use correct addy, grout and mastic, how will any water get behind the tiles?
and surely if it does your tiles are in trouble? am i missing the point?
confused of carshalton

**Cliff Anger** · 25-04-2008

Hi Confused

Quite simply tanking will totally ensure that your shower wont leak water into the rooms below !
you can readsome of the posts here - all adhesives are not the same. Whilst they claim to be waterproof or water resistant that only means they will not break down and dissolve in water- it does not mean they provide a waterproof barrier to prevent water passing through them hence the need for tanking. Grouts are the same.

**Sir Ramic** · 25-04-2008

Tile grout is water resistant not waterproof (unless you use epoxy) the same goes for adhesive.
In a normal light duty shower area you will probably have no problems with the tiles but when it comes to heavy duty shower use ie, big families using the shower.
Then you start to have problems, the water will not have time to dry and it will work its way through the grout and to the adhesive where it will have no where to go except the surface to which the tiles were originally fixed. If it is plasterboard then it will become wet and the board will break down.
Tanking the walls will provide a waterproof barrier that will stop water getting to the boards.
IMO tanking is not necessary on low use domestic showers. As long as good quality adhesive is used which is suitable for the job such as Bal White star and grouted with suitable grout then all will be fine.
Depending on the tiles being fixed you may want to use a bagged adhesive if fixing larger formats. I know a lot of tilers here only use bagged adhesives but thats down to personal preferences.

25-04-2008

thanks for your replies!...interesting reading.
I have been using keraquick/keraflex lately, would this be one that requires tanking then? what about straight on to hardibacker in a shower, lets say heavy use to be on the safe side.
Is there an adhesive and a grout that would not require tanking? you mentioned epoxy, is this user friendly?
ps if you have water behind the tiles, surely they will fall off eventually?
thanks in advance
slightly less confused of carshalton

TilingLogistics · 25-04-2008

My answer is Tank it and be safe rather than sorry. Even if a shower is low use with one family Imagine they sell the house and it become high use. For what a bucket of tanking costs it's worth it every time and its a good add on moneywise for the tiler.

I used to have a dozen tiles fixed to a sheet of clear perspex in my van. Run it under a slow house tap and show the client the water working its way through the grout. It sold the tanking every single time

Kev

davy_G · 25-04-2008

I regularly do insurance jobs and nine out of ten of those are water damage in showers. I would say half are due to poor grouting or tiling the other half are settlement related. Anyway by the time the customer noticed the water in the next room or staining on the ceiling below the shower walls where well and truly knackered. Tanking would have stopped this damage to the walls and reduced my time & cost to retile. Tanking wont stop the water getting in if there is settlement and cracking of grout and addy but it sure makes the problem easier to resolve!

26-04-2008

as cliff anger says,

its abouts about damage limitation to other rooms and not just the tiling aspect of things.

as a plasterer i have made a lot of money via insurance claims going out to properties and replacing ceilings due to water damage. tanking is actually a plastering process which was brought about in cellars below ground level were damp was rife so why not tanking?? its a proven watertight system and can make you more money on top of your tiling and give the customer extra reassurance and peace of mind, surely thats what a pro tiler should be recommending to his/her customers, unless they dont understand it or arnt up to installing it??

**Dave** · 26-04-2008

Also just to add to this...you can use tanking membranes as well...........a lot quicker and easier than solution kits.......

26-04-2008

in response, as a professional tiler specialising in domestic work, i want to guarantee my customers that their shower enclosure wont leak, not that if or when it does there is damage limitation in place!
this is the point i have been driving at and no-one so far has convinced me otherwise!
if epoxy grout stops this, why not just use it?
also hardibacker boards are waterproof anyway.
ps i dont want to "sell" tanking i want to do the best tiling job possible.
i am happy to put the stuff on, god knows its not rocket science, i am just uncomfortable with the thought of water behind my tiles!
best regards, adam

Northern Bird · 26-04-2008

The reason why we all do tanking is because of water reaching the substrate. Tiles can be proous with ceramic being 40% porous and natural stone being 60% porous. Grout can also be porous.

Customers expect a lot from their showers and bathrooms and sometimes do not matain them correctly. The number one failure in new houses is bathroom area!!

Just think what a power shower does to grout lines after time!

Ok brief run down:

Water and plasterboard = mush
Water and chipboard/plywood = warping and popping tiles

There are two breeds of substrate:

Water resitstant and Waterproof

Obvioulsy you have water resistant plasterboard but it can still break down in contact with water and if you read the literature it says light use only.

When you have Backer boards i.e. water resistant these are boards that can absorb water and control release it back into the atmosphere however these boards do not "warp, swell./ Crack etc"

Waterproof means the water will not penertrate the substrate.

There are plus sides and downsides of all of these. The main thing is where are you at and what condition will your bathroom been in when you start. I.e. have you already had plasterboard installed? Then go for a tanking system!

Hope this helps

Just remember some prevention is cheaper than no prevention!

ross lewiss · 26-04-2008

hi northern bird
where can i get all the info i need on backerboards ie sizes, types, how to install, tech spec etc
ross

**Dave** · 26-04-2008

Quote:

Originally Posted by Unregistered

in response, as a professional tiler specialising in domestic work, i want to guarantee my customers that their shower enclosure wont leak, not that if or when it does there is damage limitation in place!
this is the point i have been driving at and no-one so far has convinced me otherwise!
if epoxy grout stops this, why not just use it?
also hardibacker boards are waterproof anyway.
ps i dont want to "sell" tanking i want to do the best tiling job possible.
i am happy to put the stuff on, god knows its not rocket science, i am just uncomfortable with the thought of water behind my tiles!
best regards, adam

If you use cement based adhesives then it will with stand as much water as you can throw at it .. so to speak...after all swimming pools are tiled in it and are immersed in water for very long times.......if the correct adhesives are used then water will not affect them..it's the substrate that needs protecting from constant wetting.......not the adhesives or grouts........if correct ones are used.....