Help!: Any tips on mechanically fixing hardi backerboard ?

[Tony Cooper]

Hi All,

Anybody have any recommendations as to the best way to mechanically fix 12mm hardi backerboard to a plastered over brick wall ?

A customer has had a job fail and asked me to fix it. A now out-of-business bathroom company fitted 900mm x 300 x 10mm ceramic tiles full height and 2 tiles wide above the bath side and 1 tile wide above the taps/shower end. The tiles have fallen off the bath side after just 6 months. (The shower side column is fine). There's only four tiles left on the wall directly above the bath, 2 wide and 2 on top. And where they meet in the middle they've bowed. At the top of the tiles there's a gap of approx 25-30mm behind the tile and the wall and the addy has de-bonded completely from wall. The plaster is completely undamaged - never seen anything like it. Apparantly the bathroom company plastered the wall one day then tiled and grouted the next, unbelievable. No wonder they went out of business.

Anyway, I'll need to pack-out the wall because the bath wasn't fixed flush to it which is probably why the bathroom company just dot and dabbed a huge amount of addy to pack the tile out so it sat on the bath edge. Customer tells me the wall is brick which was then plastered over.

So, my thoughts are to mechanically fix cement boards (approx 4.5m2), so how would you guys go about mechanically fixing them (into a 6mm bed of adhesive of course)

Thanks in advance.

Tony

[Thespanishtiler]

i would use marmox or wedi boards rather than cement boards

check out their web sites for fixing instructions

12mm cement boards are more suited to fixing on studwork imo

[blocko]

I can second what spanish said......... see my recent post re marmox.... Marmox ..... a quick guide to their products

[Tony Cooper]

Thanks Lads,

I'll take a look at that link, looks like marmox or wedi it is.

Tony

[hillhead]

Take no chances on this one Tony, I came across a similar one before and I thought it was a stud wall behind. Not so as the tiles were hanging with grout.
Mine wasn't a wet area so I plasterboarded it.

[Richard Edwards]

There are several boards like Wedi / Marmox / Lux / Nicobond etc on the market and they are all very similar. I would consider removing all the plaster and getting back to the brick. Primer the brick with a couple of coats of Acrylic Primer [Not PVA!!!!] and select the thickness of board you need.

Now then you can dot and dab these boards using polymer modified cement based adhesive or the manufactuers own ady if you wish and then to be really safe you can fix long screws with special 35mm recessed washers into the brick and the countersunk design of these washers will result in a spread loading and a flush surface to tile directly onto. Use tanking tape and special adhesive for water sensitive areas

Bob is your uncle and probably your auntie too