Fix and Finishing FAQ

Frequently Asked Questions

Can I paint, tile or apply direct wallpaper onto the board?

Paint should be applied as a mist coat and two undiluted top coats

Tiles can be fixed directly. In splash back areas such as showers, a waterproof system is recommended. 

All wallpapers except vinyls can be applied without priming. On vinyls, use a low water content paste. 

Can standard drywall screws be used to fix fermacell? 

No. fermacell Gypsum Fibreboard is a very dense board and standard fixings will either break or result in failure of the finished construction. 

fermacell screws are purposely designed to countersink into the board's surface. For more information, you can download a PDF of the fermacell screw Product Datasheet here

Can I skim onto the board?

This is based on personal preference as fermacell will accept direct decoration. 

Should you wish to skim fermacell Gypsum Fibreboard, we recommend that a PVA Sealant is applied first, as some finishing plasters can craze in certain conditions. Typically a multi-finish plaster will give a better result. 

When skimming, jointing must still be carried out using correct fermacell jointing techniques.

What is fermacell FST?

fermacell Fine Surface Treatment (FST) is a ready mixed product designed for the surface application of fermacell Gypsum Fibreboard to create a smooth finish.

How thick can I apply the FST?

We advise using a trowel or a spatula to apply the FST onto the whole wall surfacethen scrape it all back off again, with the same tool. The final thickness should be approx. 0.5mm. What you can’t scrape back is bound into the texture of the board and leaves a smooth finish. The excess goes back into the tub to be re-used for up to a year. 

How long does it take FST to dry?

45 minutes.