Please refer to the heating manufacturer's detailed instructions. Most manufacturers will require the heating to be slowly brought up to temperature over a number of days. The heating should not be turned on until the flooring glue has fully dried (typically 24 hours). All floor coverings should be applied only after the heating has been tested.
A As long as you are reasonably fit, Yes. The board is heavier than standard wall board, so if you are tackling the project on your own, use the One Man Board formats. Otherwise, having read the manual, all of the installation steps are straightforward and logical. If you are using Fermacell for the first time, start in an area which is out of sight (an airing cupboard for example) where you can practice your technique.
A About three times the price of plasterboard in material terms. But since boards don't stay up on their own, you also need to factor in the cost of the other elements. The studwork is about the same, but you will save money because you don't need noggins. You need to allow for insulation in both cases. Installation is about 25% more expensive (see the question above). All in all, a like for like partition using Fermacell will cost about 20% more than a standard wallboard equivalent. Except that the standard wallboard one isn't equivalent - the Fermacell variant is impact resistant, carries wall mounted fittings anywhere on the board, has incredible acoustic performance (from 52dB on steel stud compared to 45dB for wallboard) and is a moisture rated, one hour firewall. To achieve this with plasterboard you must use specialist boards, multiple layers and so on.
Where Fermacell really wins is when you are considering skimming plasterboard. Assuming you can find a plasterer, the result will take 3 days to dry out and have added anything up to £6 per metre to your costs. Fermacell is already abrasion resistant, but if you want skim coat smoothness, use Fermacell FST (Fine Surface Treatment) - a ready mixed face filler that binds into the surface of the board and is DIY/non-skilled trade application that dries in 30 minutes and is ready to paint in 45.
In performance terms, the resultant Fermacell construction is closer to a solid masonry wall than a drywall partition.
A Once the Jointstik adhesive has dried, it can be removed with a scraper and the glue line and screw heads filled with filler. The joint area is then finished with a filler slurry applied with damp decorator’s sponge in a circular, dabbing motion. This will match the joint to the slight texture present on the rest of the board. A mist and two top coats of undiluted paint can then be applied. For very smooth finishes use Fermacell FST.
A Yes. This has been recently introduced to allow the high performance benefits of Fermacell to be used in conjunction with conventional dry lining techniques. The product is available in 2400 x 1200 x 12.5mm format with a tapered edge on the two long sides, and in the handy 1200 x 1200 x 12.5mm 'One Man Board' with a tapered edge on all four sides. The product is available to order through Fermacell distributors.
A On timber structures, Fermacell may be fixed using special staples. Recommendations on staple dimensions are contained in the handy guide, and staple guns and accessories are available for hire or purchase through trade outlets. Contact the manufacturers for details of local outlets. BeA (01482 861075), Haubold (0151 479 3010), SENCO (01925 445566) and Young Black (01793 838400) manufacture a range of tools suitable for this type of work.
It is also possible under special circumstances to nail Fermacell to steel studwork. Please contact the xella hotline for further details.
A It is important that the screw bites quickly into the steel and holds it tight against the back of the board, rather than forcing the steel away, which can happen with slower screw speeds. If the stud is distorted in this way, lipping of the boards may occur.
A No. Fermacell is a very dense board and standard fixings will either break or result in failure of the finished construction. All Fermacell products match the board characteristics – others do not!
A Yes, within certain limits. Fermacell is a very rigid board and bending should be done with care. Standard 10mm board can be installed in curved partitions (or ceilings) with a radius down to 4m. For curves tighter than this, the boards must be pre-curved by wetting or steaming over a form, and then allowed to dry to their normal moisture content prior to use. Please refer to page 45 of the Orange book for further details.
A No. Fermacell may 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. This will prevent excessive quantities of dust being created (the dust doesn't contain anything harmful, but avoidance of exposure to dust generally is good practice). Battery powered skillsaws are ideal.
A Boards up to 6000 x 2540mm are available, and we can also make boards as small as 400mm x 400mm. They must be ordered through a Fermacell stockist with a minimum quantity of 200m2. This allows elimination of waste (you can have a board tailored to your floor to ceiling height), or to reduce jointing costs - the cost of plasterboard and tape and jointing is about the same square metre cost of a Fermacell board, so you get the benefits of Fermacell for free. This is particularly relevant if you are manufacturing large panels (e.g. SIPs) or modular systems. Also, if you don't have joints in a wall, they can't crack.
Please note that large format boards require special handling and storage - more information is available from the Xella hotline +44 (0)870 6090306
A It's heavier, and not as easily cut as plasterboard. You should therefore allow more time, or more labour for the project (about 25% on average). Unless you are using the tapered edge board, the installation sequence does not follow the traditional tacking and jointing technique - each board is edge glued to it's neighbour in sequence which generally lends itself to a three man team rather than two (one for gluing and screwing, and two for placing the boards). The glue dries overnight and is scraped off, the screw (or staple) heads stopped with Fermacell filler and the board finished according to specification.
A Paint should be applied as a mist coat and two undiluted top coats. Tiles can be fixed directly. In areas such as showers, a waterproof mastic is recommended. All wallpapers except vinyls can be applied without priming. On vinyls, use a low water content paste.
A Yes, although it is not necessary as Fermacell will accept direct decoration. The board is pre-sized, but we recommend that a PVA sealant is applied first as some finishing plasters can craze in certain conditions. When skimming, jointing must still be carried out using Jointstik and joints should be taped. A finish identical to skim plaster can be achieved by using Fermacell FST which is dry in 45 minutes, is non-skilled and costs a fraction of the costs of specialist plasterwork.
A It's a combined filler, sealant and adhesive. Joints made with Fermacell will won't crack. It also sets very hard, so don't be tempted to put too much on or you will spend all your time sanding it back. When mixing it, use clean tools, bucket and water - every time - and put the water in first, adding the filler after. Once the filler has soaked up the water, WAIT - allow it to slake for 5 minutes before gently mixing it into a consistent goo. This way, it will last up to 35 minutes before going off. If you mix it mechanically, it will set prematurely.
A Fire ratings come from the overall construction, not the individual board. A variety of constructions are shown in this website, together with datasheets.
A In general, use Jointstik whenever possible. If the edges of the boards are uneven – for example when using offcuts, then Fermacell Joint Filler should be used. Because Jointstik takes 24 hours to harden, the filler method can be used if a job needs to be completed quickly. Remember – do not mix the two techniques – Jointstik is not a gap filling adhesive and glues the boards together as they are installed; Fermacell Joint Filler is applied once all boards have been fitted to the 5-7mm gap left between the boards.
A Allow the first board to extend past the corner of the stud by its own thickness (due to shrinkage, best results are obtained using metal stud). Fix the second board leaving a 5-7mm gap between and fill using Fermacell Joint Filler. If using Jointstik, fix the first board flush with the corner of the stud, apply a bead of Jointstik along the edge of the fixed board and fix the second board. Angle beads are not necessary. Once the boards have been jointed and finished, it may be preferable to profile the external corner into a small radius (2-3mm) to mimic the effect of a plaster bead. On partitions where a sharp edge is required (typically in commercial applications), a paper reinforcing tape can be used in conjunction with FST.
A It can be used in domestic showers or bathrooms, or in semi-exposed applications such as soffit, and areas of high humidity (up to 80% Rh). It's OK for carport ceilings, but not for facades. Fermacell can be installed before the building envelope is complete, but ensure that it is not directly exposed to rain, or is in contact with standing water.
A Not recommended. This is because, whilst the pool area may be ventilated mechanically, air conditioning can break down causing the relative humidity to exceed 80%Rh. In these conditions, the board can soften and sag.
A Whilst Fermacell is a moisture rated board, it is not waterproof and boards with elevated moisture content should be allowed to dry prior to use. Specifically, damp boards cannot be properly jointed, and may be subject to movement as the moisture content changes. We recommend that they are stored flat off the ground in a dry room. Under these conditions, boards should reach a normal moisture content within 48 hours if the temperature is >15 degrees Celsius and relative humidity of the surrounding atmosphere is <70% Rh. If you are in doubt, the moisture content may be measured by using a moisture meter, and must be no more than 1.3%.
