Tiling over plasterboard? What weight will it take?

Due to the fact we’re suppliers of tile adhesives, backer boards, movement mattings and many other tile associated tools and equipment, we often get asked about what substrates can be tiled on.  The truth is – nearly all substrates are suitable to take tiling if they are properly prepared and the correct adhesive and grout is used.

But, there is one key thing to take into consideration when deciding to tile over different substrates – the weight per sq metre the substrate can support without failing.   Some examples of substrates commonly used on walls and commonly tiled over are shown below with the weight per sq metre they can support safely:

Gypsum plaster (finish plaster)  - 20kg per sq metre

Plasterboard (no skim) – 32kg per sq metre

Tile Backer Board (cement based) – Up to 50kg per sq metre (this is an approximation – refer to the board manufacturers guidelines as different brands can vary)

Sand cement render – up to 50kg per sq metre (very heavy tiles may require reinforcement)

Understandably different types of tiles will have different weights per sq metre.  The most common types of tile are ceramic, porcelain and natural stone and each product will have different density’s and therefore different weights per sq metre.  As a rough guide we’ve shown some approximate weights per sq metre for each type:

6mm thick ceramic tiles - 10kg per sq metre

10mm thick ceramic tiles – 17kg per sq metre

10mm thick porcelain - 23kg per sq metre

12mm thick porcelain – 28kg per sq metre

7mm thick natural stone – 19kg per sq metre

10mm thick natural stone – 27kg per sq metre

20mm thick natural stone – 55kg per sq metre

On top of the weight of the tiles, the weight of the adhesive used to fix the tiles should also be taken into consideration.  A typical guide is to allow in the region of 5kg per sq metre for a 3mm solid bed of adhesive.

So, in summary, careful consideration should be taken before tiling to ensure the substrate being tiled on is sufficiently capable of supporting the weight of the tiles that are going to be fixed to it.  If it’s incapable then you’d need to replace the substrate with another substrate that would be strong enough (replacing plasterboard with tile backer board for example).