We tested it with the robinson wheel, basically you add weight as the wheel goes over a floor until failure. The install with 12 x screws performed just as well as 39. We say its the minimum, more is always better but 12 we will warrant as long as our install guide is followed
Like any product we have installation instructions. If they are adhered to the product works no problem with the 12 x screws. But there must also be adhesive under the board, alkaline resistant tape, the boards staggered, 5mm gap around the room perimeter and most importantly the substrate is solid.
The drop to 12 x screws is designed to speed up and make the install more cost effective. Nothing wrong with putting more in of course. The markings (circles) are remaining on the board.
You really need to clarify the tile or stone fixing method though.
A simple reference to BS5385 would cover you as a company.
The first time some moron spot fixes 20mm marble to Hardibacker and it falls off destroying something or someone - you have a potential problem because "it holds 200kg p/sqm".
Kerdi board, honestly say 98% of the quotes I do wouldn’t accept price of them for prep work!
There are plenty of alternatives just as good at fraction of cost.
You really need to clarify the tile or stone fixing method though.
A simple reference to BS5385 would cover you as a company.
The first time some moron spot fixes 20mm marble to Hardibacker and it falls off destroying something or someone - you have a potential problem because "it holds 200kg p/sqm".
Our products are tested beyond the required capability. For example if you search our social media we have images showing 200kg of weight on only a 300mmx300mm plate. The weights are the equivalent of over 2 metric ton being held on a board.
Now if someone were to spot fix then as with any product you could have an issue. No real tiler spot fixes. Anyone who does is asking for trouble.
