203 x 406 x 12mm travertine tiles

[Martyn hoare]

Evening all, so I am going to fix these tiles to cement board (going to go with hardibacker) which is capable of supporting the weight. My question is, must the Cement board be fixed to the actual blockwork (thermalite) or will we get away with grip filling the board to the plaster, which is skimmed over the blocks and then fixing with masonry screws, followed by taping and jointing. Don't quite fancy hacking off plaster if it's unnecessary....thanks!

 

[One Day]

If you only bond the boards to plaster skim, then your weight maximum is 20-25kg!
You'll need to get some mechanical fixings into the block if you want the benefits of the weight bearing board.
Personally, I'd use wedi or similar. Just dot n dab onto the walls, then fix through the dried dabs into the block.
Far easier to use than hardi.

 

[One Day]

Masonry screws will be no use in thermalite. You'll need something from fischer. I had some good fixings from screwfix but can't recall exactly what i used. They were plastic plugs which twisted up into the block and were very strong.

 

[White Room]

6-12mm can be used
HardieBacker® • The rear of HardieBacker® must be wiped down to remove dust. • All existing old dry lining should be removed as it has the potential
to fail further.
2. Use a high strength gap filling adhesive • Place 3 vertical 10-12mm beads of high strength, single part, gap filling cartridge adhesive, evenly down the back of the board. • Press board firmly against the wall into the desired position.
3. Fasten HardieBacker® 6mm with masonry anchors • Fasten HardieBacker® with 9 (6mm x 60mm) stainless steel screws into brown wall plugs. Screws should remain 100mm from the top and bottom edges and 50mm from the left and right edges. Ensure min 50mm embedment into the wall. • Do not overdrive the screw; it must be flush with the face of the HardieBacker®.
4. Tape joints prior to tiling • Prior to setting the tiles, embed 50mm alkaline resistant Fibatape across joints and feather tile adhesive to leave a 150mm wide joint.

 

[One Day]

^ which is why i hate hardibacker.

 

[Martyn hoare]

Thanks for your reply. Glad you said that....ive looked them up and found Fischer fixing on the screwfix site. A diagram there shows the plug twisted up which must be how the screw anchors itself in aerated blocks. Going to take a few tiles and plaster off tomorrow and see what exactly the wall is built of. It is a party wall so could be concretes, although I know the shower wall is thermalites. This travertine is going in a bathroom so I want to get it right first time when it comes to weight moisture etc

 

[WetSaw]

You might find that the plaster comes off with the tiles anyway so you might as well strip it out then make the decision about preparation.

 

[Dumbo]

Masonry screws will be no use in thermalite. You'll need something from fischer. I had some good fixings from screwfix but can't recall exactly what i used. They were plastic plugs which twisted up into the block and were very strong.

I'm in your camp but I have used the plastic dowels with the solid plastic insert place where I get them call them spanners. Very I think and quick.

 

[Qwerty]

Spankers. Would be my choice

 

[One Day]

Spankers. Would be my choice

I tried them in thermolite - no good.
These are what I used and found to be very strong: http://www.NoLinksToThis/p/fischer-high-performance-universal-plugs-ux8-4-5-6-x-50mm-100-pack/20669

 

[John Benton]

Those are the plugs I buy all the time, one of my suppliers even sells them individually, it's like one of those old traditional hardware stores. They are suitable for any type of substrate

 

[Qwerty]

I must have been lucky as I have found Marmox spankers fine in thermolite

 

[Dumbo]

I must have been lucky as I have found Marmox spankers fine in thermolite

Same as

 

[Dan]

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