Help aqua board has been skimmed

[JVC600]

CAN YOU OFFER SOME ADVISE FOR THIS SITUATION PLEASE ON BEST PLAN OF ACTION .

THE WALLS OF MY BATHROOM HAVE BEEN DOT AND DABED WITH NORMAL PLASTER BOARD .

I HAVE FITTED MYSELF IN THE SHOWER CUBICLE AREA AQUA BOARDS.FITTING THESE TO A LATTED FRAME USING THE AUA BOARD SCREWS AND SEALING EACH BOARD WHERE THEY JIN WITH THE AQUA BOARD JOINTING SEALANT.

HOWEVER THE PROBLEM I HAVE NOW IS I GOT A PLASTERER IN AS I WAS RECOMMENDED TO GET THE NEW PLASTER BOARDS SKIMMED BEFORE TILING.

THE PLASTERER HAS SKIMMED THE NEW BOARDS AND THE AQUA BOARDS WITH THISTLE MULTI FINNISH PLASTER , PRIMING FIRST THE AQUA BOARDS WITH PVA THEN SKIMMING THEM WITH THISTLE MULTI FINNISH .

WHAT CAN I DO TO RESOLVE OR RECTIFY THIS PROBLEM SO I CAN TILE THE BATHROOM .?

AM I CORRECT IN SAYING I COULD JUST TANK OVER THE SKIM PLASTER AROUND THE BATH AREA ?

CAN I JUST TANK OVER THE AQUA BOARDS NOW TO SOLVE THIS PROBLEM ?

IF SO WHAT TANKING SUBSTRATE SHOULD I BUY ?

I HAVE FEARS THAT THE TILES MIGHT JUST SIMPLY FALL OFF THE AQUA BOARDS IN THE FUTURE IF I DONT DO SOME THING WITH THEM.

I ASKED THE PLASTERER WHY HE HAD DONE THIS HE SAID THATS HOW HE SKIMMED BATHROOMS .I THINK HE HAS DONE IT IN ERROR

THE BOARSD IN QUESTIONS ARE KNAUF AQUA BOARDS

I DONT PLAN ON PUTTING HEAVY TILES ON THE BOARDS.

PLEASE HELP, I REALLY DONT WANT TO HAVE TO TAKE AQUA BOARDS DOWN AND PUT NEW UP ....


CAN I JUST SIMPLY TANK OVER THEM AND AROUND THE BATH AREA??

[mikethetile]

what tiles are you using

[JVC600]

dont know what tiles am going to use as havent bought any yet.

more concerned about this aqua board and them been skimmed

[mikethetile]

theres a weight issue with skimmed plaster supporting tiles

[TF Ed]

as mike said the weight ratio has now just been reduced due to the skimmed surface..

you could overboard again? and this time dont plaster them..again as mike said, what tiles are going up?

ed

[doug boardley]

and can you turn your caps lock off please

[Alan.P]

Hi JVC600, interesting, I've never come across this before, skimming of aqua board that is, so can't really say what the implications would be regarding adhesion to the board and what it would do to the weight issues, what I can say though, is for future reference, DO NOT skim plasterboard, you reduce the weight it can handle by a third.

[TF Ed]

the implications are this, if a wall has been skimmed, whether thats backing plaster, boards, sand and cement etc then the weight ratio for holding tiles will be reduced to 20kg/m2 ...

skim (board finish/multi finish) is a finishing coat, is quite a weak compound and as its only applied between 2mm and a maximum 5mm, then it isnt very strong in adhesion...hope this helps

[JVC600]

thanks for the replies. so i guess the best way forward is to buy small to meduim size tiles . was thinking of buying ceramic tiles .nothing that over the top.

plasterer has skimmed the knauf tile backer boards (called aqua boards in error).

could i just rough the skimm up a bit on these boards to give a better key with sand paper??

[mikethetile]

its not getting the tiles to stick to the skim that the issue here, its the bond between skim and board thats weak plus the skim itself tends to delaminate as its structure is too weak

if your going to use small ceramics you will probably get away with it, dont forget to use primer G on the skim and use a powdered addy not tubbed

have a quite word with your plasterer and educate him before he messes up someone else bathroom

[mikethetile]

forgot to mention, it would be a good idea to use a tanking kit in the wet areas

[JVC600]

would i just simply use the tanking kit over the skimmed plaster boards as well as over the skimmed cement based aqua boards before i get it tiled?

the bath and shower are tray are not fitted yet.

what the best tanking kit to use??

[diamondtiling]

Hi you need to say what size tiles you are using and the weight of them as that is an important factor right now.

[JVC600]

ceramic tiles 30cm by 20cm i think, mrs has seen these in topps tiles the other day

[JVC600]

would u advise on using a wall paper steamer on thse aqua boards to remove the skim coat of plaster ?

then use a tanking kit on them ??

i believe the plaster will not stay on the cement boards ?

any ideas ........?

[JVC600]

i had a closer look at the skim plaster ON THE AQUA BOARD.
i took a scraper to the boards and the plaster just comes off in large bits.
so it looks like it has confirmed what i believed already.

u can not skim knauf aqua boards , .


am i correct in asuming i just need to tank the boards over with a tanking kit ??

[mikethetile]

im pleased you found out before tiling as that would have been disastrous

has all the plaster come off cleanly or is there a residue left

[JVC600]

the plaster skim has come off in little pieces ..
very brittle
well i am going to get the rest of the plaster skim off these boards in next few days .

i will then tank over the boards with the bal wp1 kit i think .

that should sort the problem .

i know now gypsuim plaster skim and knauf aqua boards dont go together.

i think to elimante the aqua boards been been originally pva i will wash them off with water then give them a quick light sand with 180 grit sand paper before i tank them .

should be ok then ???

[Ken Bruty]

I would still be concerned whether the boards are suitable to tile at all, because pva was used, and it's unlikely to have come off with the plaster, therefore, you still have a skin over the aquapanel which the tiles would be stuck to, and the bond is only as strong as the pva skin. Aquapanel should never be primed either, to be safe I would replace them completely imo Also the dust from aquapanel is harmful, so I wouldn't recommend sanding that either.

[whitebeam]

A dry cement board sucks the moisture out of new plaster and causes it to crack and delaminate

[mikethetile]

Kens right

im concerned about gypsum still being present on the surface of the aquaboard as well as tanking aquaboard

if you want to tank it why not just rip it out and use ordinary plasterboard

[JVC600]

thanks for the replies .

i took a wall paper stripper to the boards last night .
the plaster just fell off afer about 10 seconds worth of steaming

have spoke to kanuf technical and bal reference tanking them .

they said as long as i can get the plaster off they should be fine .

as a safe guard a light sand with 180 grit should get the key grip back after washing them off with water .

as for taking them off they cost over £75.00 to replace so dont think i want to to do that .

tanking them will make them totaly water proof , so hence use the bal primer them the tanking kit .

i think this will do the job ??