what's special about aquapanel screws ?

[sm_jamieson]

Anyone used the special aquapanel ceramic coated screws ? Are they an expensive rip-off ? If not, what is the special purpose of them ? I note they are self-tapping - I will need to fix some into steel square section. I guess I would need to pre-drill for screwing into 2mm steel. Simon.

[Lobster]

I've been waiting with interest to see if you got any replies to this as I'd like to know too! They're certainly expensive. I've always used them myself on the basis of not wanting to risk spoiling the ship for a ha'porth of tar.

Anyway, in the absence of any response I've been sufficiently motivated to give the Aquapanal technical support number a call today.

According to them, it's the ceramic coating which is most significant; needed because the board is cement-based. The board is guaranteed for

10 years, and they don't want 'failure' to occur do the use of inadequate screws. I asked why galvanised screws wouldn't do and was told it was because of the nature of the board.

My guess is that the ceramic coating is tougher than a galvanised coat, and because the board is very hard and brittle, maybe it could abrade away a galvanised coat while it's being screwed in?

Lots of technical info at: by the way.

David

[sm_jamieson]

There are other cement board screws available, and they all have a non-corrosive coating and self-drilling heads to countersink themselves. I'm sure any of them would do. The hardibacker instructions say you can also use galvanised roofing nails. But I guess the board would not be guaranteed without using the special screws. What is the best place to get them from ? Cheers, Simon.

[Lobster]

Expect you're right. Are these other screws any cheaper? I've only ever used Aquapanel myself - I just get it from Wickes, which is where I get the screws from. (ISTR there was a list of stockists mentioned on the link in my last posting.)

David

[sm_jamieson]

I'm going to go to this place

have a general squint at the various cement boards sometime soon. I've not used any type of cement board yet, and I need to gen up on all of them. I'll ask about the screws if I remember. There's a USA cement board called Durock that you cannot get over here, but there is some very useful general information about cement boards available if you search on it. They recommend jointing / glueing the stuff with latex-modified mortar, AKA thinset mortar etc. Simon.

[dom]

I would expect stainless steel screws to be fine, though the screwfix ones tend to be rather brittle.