Poss Tanking problem?

[Lucasb]

Hi Folks,

wondered if you could offer some advice?

I decided to tank the area around my new shower bath -walls are plaster skimmed plasterboard -not ideal I know but that's what was there , and I am now having a powershower installed. I used the dunlop kit -primed with neat APD, let it dry and then painted on the tanking coating. Problem is the tanking coat seems doesn't seem that firmly 'attached' -I can easily rub it off -is this normal? don't want to tile onto a surface that'll come away at the first opportunity!!

many thanks!

Lucas (newbie)

 

[mikethetile]

no it shouldnt rub off

the paint should be given 2 coats cross brushing each other and finish about 2mm thick, youved used apd which is correct, I have used the paint on tanking kits and tbh I dont trust them as the minimum requirement to waterproof isnt easy, theres too many variables in drying properly and giving a 100% coverage and ive been decorating for 30 years, the waterproof mesh is better and easier to use

were the walls emulsioned before you applied the primer

 

[jay]

hi no its not normal should be firm how olds the plaster and have you taped the internals (bead breakers)

 

[mikethetile]

oh and welcome Lucas

 

[mikethetile]

its the primer they supply in the kits Jay. its basicly an acrylic primer

 

[Lucasb]

no it shouldnt rub off

the paint should be given 2 coats cross brushing each other and finish about 2mm thick, youved used apd which is correct, I have used the paint on tanking kits and tbh I dont trust them as the minimum requirement to waterproof isnt easy, theres too many variables in drying properly and giving a 100% coverage and ive been decorating for 30 years, the waterproof mesh is better and easier to use

were the walls emulsioned before you applied the primer

Hi -thanks for the response.

no walls were bare plaster over board -was plastered about 6 months ago. before tanking -or trying to tank! I very lightly abraded the surface with a fine sanding pad, brushed it down then primed with neat apd. let that dry then brushed the tanking 'paint' on -now been drying for several days.

prob try the mesh next time -been suggested I scrape it all off and forget the tanking.

 

[mikethetile]

just checked the spec on the Bal site, Bal make apd for dunlop as Bal owns Dunlop

for plaster sufaces its neat application but on dusty surfaces they reccomend 1:1

but as the primer had dried before application of the tanking I cant see that being the problem

 

[Lucasb]

ta for the reply.

yes, was taped -looks like its all going to have to come off I guess?

 

[mikethetile]

I would tank if your fitting a powershower

waterproof grout doesnt breakdown when wet but still lets water through, leaving out the tanking may cause problems further down the line

 

[jay]

if its not sound yes its got to come off did you stirr the waterproofing liquid before applying

 

[Lucasb]

Hi Jay,

will confess I didn't stir it that well, seemed pretty homogeneous when I opened the container -you reckon thats it? damn....

 

[jay]

possably always pays to stirr contents on slow speed mixer but it sounds more like the primmer hasnt worked (to much suction)

 

[Lucasb]

Thanks for all the advice guys -its very much appreciated!

Will take it off and try again -one last question tho' just how firm should the bond be? -for example if the tanked surface is abraded -e.g if I catch it with a tile corner or similar and it 'digs in' should the tanking layer lift off the primer if rubbed then (sorry its such a particular question -never used the stuff before -and 'feelin' my way a bit!)

cheers!

 

[jay]

you need a solid substrate to apply membrane to not dusty or soft once membrane is on it should be firm and yes care is needed with it as it can be damaged (its a bit like paint on the wall )so take care if on floors extra care needed hope this helps

 

[Lucasb]

Hi jay,

thanks again -you've been very helpful with this -and very understanding of a newbie!

cheers,

Lucas