Recently it has been asked if Aquapanel can be fixed using the direct bond method. I was not sure of the answer and so I contacted Knauf technical, who kindly answered the question for me-

The Knauf Aquapanel can only be installed mechanically using a frame
system. This board cannot be direct bonded using the bonding compound
for two reasons:
1) The board itself is cement based and is not compatible with the
bonding compound which is gypsum based. As they are not compatible, the
bonding compound will not adhere the board. If you do try this, you may
find that the board comes off the compound within a few days.
2) The board does allow moisture through it over time. For this reason,
you have to ensure an air gap to the back of the board for the moisture
to disperse. This is done by ensuring that the board is fitted onto a
frame.

If you are using a metal frame, we would recommend using the Knauf
Apertura Lining systems (explained in the attached in detail). If using
timber studs instead, a minimum depth as recommended by the British
Standards is 38mm.
(This is also gives you the option of adding insulation between the
frame should you need to increase the thermal performance of your
wall.)

Just elaborating the point above regarding moisture through the board:
The board itself is not affected by water. This means that it simple
allows the moisture through it without affecting its stability or
performance. This is designed as such so that, should your tiling or
grouting fail and water finds its way to the back of the boards, it will
not cause the board to fail, causing the rest of the tiles to come off
like plasterboard would.
For domestic use, the level of waterproofness and water repellentness
you require can be achieved by the tiles alone. For commercial use, we
would recommend a polythene sheet fixed to the frame prior to the
boards.

For your information as well, we recommend tiling to commence onto the
smooth side, and you should use a cement based flexible tile adhesive.


Here you can download a copy of the Knauf Aquapanel Brochure

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DIY | Donnas dream house

I'm confused.

Knauf recommend installing onto studs giving a minimum 38mm air gap to allow for the dipersal of any penetrating moisture, sounds reasonable enough. But then for a commercial installation they recommend a sheet of polythene fixed to the studs under the boards. Surely this polythene will prevent the air gap doing anything useful?

Am I missing something?

It looks like British standards recommend the 38mm gap.

The polythene will stop any moisture from effecting the timbers or the air gap as no moisture at all will be able to penetrate it.

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DIY | Donnas dream house

but the cement would stay water logged!

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Hinton Heating

Not that I'm planning to do this, but what if you used tile adhesive or cement instead of dry-wall adhesive? Wouldn't that work?

I doubt it, the point behind using battens is to let it breathe. You need an air gap for the moisture to disperse.

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DIY | Donnas dream house

Yeah, but I'm not talking about a solid bed of adhesive, just dot 'n' dab style blobs, then there's plenty of air.

I thought the original point was that you shouldn't use dry wall adhesive as it won't stick to AP - so my point is why not use something else? IMHO dot 'n' dab is quicker on a blank wall and you don't have to worry about uneven brickwork. Besides which screws potentially weaken the board.

Anyway, I've got a few offcuts of aquapanel and plenty of drywall adhesive, cement and tile adhesive - so I can put it to the test (just for the hell of it!) if I have time this weekend... :)

Drywall adhesive is much stickier than tile adhesive and sets like rock. I am not sure that tile adhesive will set as hard, especially if it is blobbed!

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DIY | Donnas dream house

I rarely use Aquapanel for walls anymore, it's OK for around baths and boxing at the end of baths but I don't ever tank onto it anymore.

If I'm tanking then it's plasterboard on first then Tank.

Aquapanel takes at least four times as long to fit and is much, much more expensive.

I'm inclined to agree with bathstyle - I'm not going with AP for the ensuite (after I finish the bathroom), I'll just plasterboard then tank. Plasterboard is just so much easier to cut and mount...

aqua panel cuts in exactly the same way as PB. just score it with a knife and break.

Plasterboard is much easier to score...

aqua panel cuts in exactly the same way as PB. just score it with a knife and break.

Plasterboard is so much easier to cut and mount

I agree

as i said before

aqua panel cuts in exactly the same way as PB. just score it with a knife and break

now if it is quicker is a totally different point.

let me know if you lot are struggling with it!