FAQ

 

Frequently Asked Questions

 

How long has fermacell been available?

About 40 years – it was first produced on a commercial scale in Germany in 1971. It’s been in the UK since 1989.

 

Can I install fermacell myself? 

Yes, as long as you are reasonably fit. The board is heavier than standard wall board, so if you are tackling the project on your own, use smaller sizes ( 1000mm x 1500mm/ 1200mm x 800mm/1200mm x 1200mm).

All of the installation steps are straightforward. If you are using fermacell gypsum fibreboards for the first time, start in an area which is out of sight ( an airing cupboard for example) where you can practice your technique.

 

Can I use fermacell gypsum fibreboard to line a wood burner?

No, but you can use our cement based Powerpanel H20 board.

 

What’s different about fermacell to standard plasterboard?
fermacell is heavier, stronger and denser than standard plasterboard. Radiators and cupboards can be fixed directly without the need of  special fixings. You do not have to skim fermacell and you can wallpaper or tile directly onto it. If a skim type finish is required you can use fermacell Fine Surface Treatment (FST). 

 

Can I skim fermacell gypsum fibreboard?

Yes, although it is not necessary as fermacell will accept direct decoration

- The board is presized, but 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, see fermacell Handy Guide for more details

- A finish identical to skim plaster can be achieved by using fermacell FST which dries in 45 minutes and costs a fraction of specialist plasterwork.

 

What's fermacell FST?

fermacell FST is a ready mixed product.  You put it onto the whole wall surface (with a trowel or a spatula) then 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 and the wall will be dry and ready to paint again in about 45 minutes.

 

What about joints?

Tapered edge or square edge fermacell is available – the square edge is either fixed leaving a 5mm gap between boards which is later filled using fermacell filler – or you can use fermacell  Jointstik glue on the edge of each square edge board, then butt the next board up to it. This glue takes about 24 hours to dry and it creates a very strong joint. Once the glue is dry  scrape off the excess from the joint, make good with fermacell Joint Filler and then in both cases apply fermacell FST over the whole wall, for a skim type finish.

Tapered edge boards are fixed to the sub frame with the boards dry butted. Once installation is complete, the boards can be jointed using fermacell joint filler. Apply filler to the joint, ensuring that the central "V" is fully filled, then bed paper tape into the joint and apply a second fill. When the filler is dry, apply FST over the whole wall. It’s a cross between the speed of the tape and joint, but the flat finish of a skim.

 

How much does it cost?

fermacell board is more expensive than standard plasterboard but with fermacell :

- noggins are not required - you can hang furniture directly from the boards. 

- fermacell is fire, sound, impact and moisture resistant –  you can use it in any room in the building.

- All in all, with the increased speed and reduced cost of finishing, fermacell wall could cost around the same as a plasterboard, skim-finished wall. Making the final installed cost as competitive.

 

Do I need any special tools? 

No. fermacell board can be cut with standard woodworking tools. When using a circular saw, use a vacuum attachment, select a blade with fewer teeth, a maximum of 16 is advisable - and reduce the cutting speed. You can also router and plane it.

If you want to score and snap it use a fermacell knife – its blade is very strong, more like a tile cutter, or just use a good quality stanley knife.

 

Can I use standard drywall screws to fix fermacell ?  

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

We advise the of fermacell screws for fixing fermacell boards as they are designed to countersink into the board surface. Traditional drywall screws are designed to clamp to the plasterboard's paper face. These will not countersink into fermacell easily. If drywall screws have been already used, then these will need to be replaced. The drywall screws can be removed and replaced with fermacell screws, thus allowing the boards to remain in place. If the screws are pulling in too much, then additional fixing may be needed.

 

fermacell screws work on timber and metal stud work. Staples can be used on timber studs at 150mm centres. Make sure they have a minimum of 1.5mm gauge wire with a 10mm head and are at least 30mm long for 10mm boards, 35mm long for 12.5mm boards and 44mm long for 15mm boards. 

Screw fixing centres on ceilings should be set apart at a maximum of 200mm.

For full installation details please download fermacell Handy Guide

 

Do I need a bead on external corners?

No – you can do this if you wish, but all you have to do is joint the boards, finish and make good with fermacell Joint Filler. A reinforced paper corner bead can be used, but due to the density of fermacell this isn't required .

 

Is fermacell a ½ hour fire board? 

A single sheet of 12.5mm fermacell either side of a metal or timber stud will achieve ½ hour fire protection, not the board on it’s own as it’s the whole wall which is fire rated. If you add some Rockstone wool insulation in the void you will achieve 1 hour fire rating.

 

Can I dot and dab fermacell?

Yes, with fermacell Bonding compound tapered edge board is best for this as the jointing is easier. 

 

What sort of studs should I use?

Our technical information states you should use a DIN Standard 0.6 gauge, metal stud with a 50mm fixing face.

These are avaliable for ether Protektor Systems - 01562 51520 or Lindab - 0121 585 2780.

The timber studs vary, 89mm CLS and 75mm x 50mm are both suitable. 

 

Is fermacell waterproof?

No, but it is moisture resistant – this means you can use it as a soffit board, underneath car ports and in kitchens and bathrooms where you can also use it as a tile backer board, fermacell will withstand up to 80% humidity (Rh).  For wet areas such as wet rooms, swimming pools and spas we recommend fermacell PowerPanel H20 waterproof wallboard and flooring.

 

Is fermacell available as a vapour check/foil backed board? 

No – use a separate vapour carrier if one is required.