Finishing

We do not recommend the use of a skim plaster finish to the board as our simple Fine Surface Treatment (FST) system gives a fast and easy equivalent that is dry in 45 minutes, ready to accept a paint finish.

Surface preperation
The surface should be dry and free of stains and dirt. Any damage or indentations must be filled with Fermacell Joint Filler and allowed to dry before any decoration.

Fermacell FST - (Fine Surface Treatment)
FST is a ready-mixed face filler used for smoothing the surface of the boards, and for filling screw heads. A 10 litre tub will cover approximately 60 m² of wallboard. FST can also be used for a feather fill over Tapered edge board joints, prior to the final finish coat as described above.

USE of FST
Apply straight from the tub using a trowel or a Fermacell FST applicator. Work on 1-2m² at a time and ensure that the surface is fully covered. Then remove the excess FST in a smoothing out motion using a trowel or a FST applicator. Do not scrape off too hard or too much will be removed. The final thickness of FST should be between .5 and 1mm thick. The FST will dry within 45 minutes and subsequent layers can be applied as required. If necessary, smooth the surface with ‘fine 240 grit’ sandpaper, prior to final decoration.

Wallpapering
With the exception of vinyl wallpapers, all types of paper can be applied to Fermacell using standard trade pastes, without priming the surface. When using vinyl papers, it is recommended that the board is primed and a suitable paste is used.

Plasters and textured plasters
A plaster finish is not normally recommended as the same finish can be achieved using FST, which is much faster and a fraction of the cost. Where plaster is being applied, all joints must be reinforced with a fibre tape fixed with PVA adhesive, and a sealant must be applied to the surface of the whole board. In addition a test area must be tried first as we do not manufacture plaster finishes. we can not guarantee the adhesion or standard of finish.

Painting
Fermacell Boards can be painted directly to achieve the best finish. Fermacell FST gives a smooth surface ready to accept a paint finish. Typically a mist coat and two undiluted top coats are required.

We do not recommend the use of eggshell paint finishes. However, where eggshell paints are used, a minimum of two coats of FST must be applied first, followed by a sealant. In all cases, refer to the relevant British standards. In all cases, the paint manufacturers recommendations should be followed.

Tiling
Standard Fermacell boards are moisture resistant making them ideal for kitchens and bathrooms. Powerpanel H₂0 should be used in constant wet areas such as wet rooms and swimming pools.

Before tiling, all areas should be clean and free from dust. If a priming coat is required, this should be allowed to dry for 24 hours before tiling work starts. It is recommended that waterproof grout and waterproof tile adhesive is used.

Constant wet areas which are subject to frequent splashing, should be treated with a waterproofing system such as the Fermacell Waterproofing System. This is a paintable system suitable for use with cement based adhesives. Tile adhesives with a low water content should be used and tiles fixed with a thin bead adhesive method, without pre-wetting.

Generally tiles should not be grouted for a 24 hour period after fixing. Follow the adhesive and tile manufacturer’s recommendations. Wall surfaces that require sealing must be protected against the penetration of water to a height of 2000 mm above the bath floor, with adequate spacing above the actual shower and bath areas. For showers, waterproofing must extend to at least 300 mm above the shower head.

Corners and penetration should be sealed with recommended sealing tapes or collars. It is recommended that all walls in any shower or bathroom are sealed against rising moisture to a height of 150mm. In all cases refer to manufacturers instructions. Fermacell recommend a maximum tile size of 300 mm x 300 mm. For larger tiles please contact our Technical Department on +44 (0) 870 6090 306.

Wet trades or wet screeding, or asphalting should be completed prior to joint filling. The adhesive method of jointing can be used prior to these applications, however, check with the our Technical Department first on +44 (0) 870 6090 306.

Gas burner heating can damage the boards due to the risk condensation and thermal shock. This applies particularly to cold interiors with poor ventilation. Rapid heating, which can result in thermal shock, must be avoided.

 

For more information please contact our Technical Department on +44 (0) 870 609 03 06 or email fermacell-uk@xella.com