Option B: JK fermafloor levelling compound with top board
Floor finish according to this option makes the floor 60 minutes fire-resistant
- Lightweight compared to wet-construction
- Limited build-up
- Fire-resistant 30-60 min
- Acoustic performance 12 dBa
To lay the fermacell Flooring Elements a completely supported and constructed underfloor is required because the flooring elements are not cantilevered. The condition of this supporting underfloor needs constructional examination by a structural engineer. There are different underfloors that are possible.
Many renovation projects consist of a wooden underfloor. This underfloor is often made of wooden beams placed at a fixed distance and incorporated into the bearing walls. The stability of the underfloor needs to be in good condition. This is a deciding factor when determining whether the floor needs to be replaced partially, completely and/or if it needs to be adapted. The underfloor needs to be completely rigid, which has enough capacity to support both the new flooring and the bearing weight of the users on the surface.
It is therefore of vital importance to expose the structure of the construction at the start of the renovation activities to determine the state the existing wooden underfloor is in. The surface may not be springy or saggy. In case of an uneven wooden underfloor, a smoothing compound will need to be applied to achieve complete support for the fermacell Flooring Elements. * The constructive underfloor also needs to be dry and level.
The structural engineer needs to approve the underfloor construction including the applied fermacell Flooring Elements. Of course, this applies for all underfloor constructions, not just wood.
*For other types of underfloor constructions, see fermacell handbook or ask for tailor-made advice.
The fermacell Flooring Elements are secured using lip welding with fermacell Flooring Element glue. The lip welding is mechanically secured using aluminium brad nails from fermacell, to achieve the needed pressure and fixate the elements during the setting of the glue. These nails do not need to be removed before grinding, because they are made of aluminium which the “floorgrinder” can effortlessly grind through.
After fixing the flooring elements, the patented “floorgrinder” from JK floorheating is used to grind slots into the flooring elements. The released dust, separated with a HEPA filter, is re-used in the JK sealing compound or in the manufacturing of the fermacell Flooring Elements. During the preliminary process a transmission calculation needs to be made according to the NEN-EN 12831-1-2017 and the derived ISSO publication 51. JK floorheating has secured the upward releases by an accredited laboratory. This can lead to a slots pattern which is made using the program liNear.
After grinding and before the heating pipes are placed, the surface needs to be cleared of any residual dust using an industrial vacuum cleaner. After this the JK flextube Inverse Soft floorheating pipes of ø 14 x 2 [mm] are laid into the slots, which are suitable for a pressure class of PN10. The heating pipes are covered by the Kiwa KOMO certification. The same goes for the manifold connections, according to BRL 5602.
After placing the JK flextube Inverse Soft heating pipes into the slots a layer of JK fermafloor primer will be applied with a roller to ensure optimal attachment of the JK fermafloor levelling compound that will be applied afterwards. JK fermafloor primer is a solvent-free floor primer used to treat the fermacell Flooring Elements. The floor primer is applied evenly and opaque onto the flooring elements with a nylon roller and has a drying time of about 45 minutes.
On top of the JK fermafloor primer a layer of JK fermafloor levelling compound of at least 5 [mm] thick is applied. This is flexible, hydraulically hardening and improved with plastic thin-bed mortar. This thin-bed levelling compound is specially well suitable for sealing the ground slots with the JK flextube Inverse Soft heating pipes and bonding the fermacell top board. The thin-bed levelling compound is evenly applied to the screed with a trowel. The levelling compound has a drying time of about 30 minutes. Optimal processing conditions are between 15 and 25 [°C] with a relative humidity of below 50 [%]. A low temperature and high humidity will lengthen the inlay, hardening and drying times. A high temperature and low humidity shortens this.
As mentioned, the JK fermafloor levelling compound serves as a bonding agent for securing the 10 [mm] top board from fermacell, which will be placed directly on top of the levelling compound. The thin-bed levelling compound is evenly applied onto the screed using a trowel, which also secures the JK flextube Inverse Soft heating pipes. After this, enough levelling compound is applied and evenly distributed to place the top boards into the wet levelling compound and thoroughly press them down. There is only so much levelling compound applied at one time as is possible to work with. See the processing directions for more information.
With this flooring system, provided with a 10 [mm] top board, a 60-minute fire-resistance will be achieved.
The floor finish can be done in consultation with Uzin Utz Netherlands concerning the needed smoothing compounds and released floor finishes (beware of release of ceramic finishing fermacell).
Uzin Utz Netherlands offers 10 years certainty with their warranty system. Uzin Utz Netherlands comes to an agreement with the client specific for their project. Free of cost. For this one of 25 experienced Technical Commercial Advisors will be linked to the projects for tailor-made advice with an extensive assessment. These advisors also have the required knowhow of the complete flooring industry, both in underfloor and floor finishing’s ranging from carpet, PVC, linoleum, natural stone, parquet and cast floors. The Uzin Utz warranty system is a system warranty and covers the complete build-up from floor primer to floor finish.
The advice Uzin Utz NL provides is clear and explicit and based on an extended assessment of the project. The products have been tested with nearly all types of floor finishes, such as carpet, parquet or tiles*. They have come up with solutions to virtually every technical issue possible which means that valuable experience can be used when giving advice for new projects.
More detailed information can be found in Uzin Utz’s Warranty brochure.
*For advice on large tiles it is also possible to consult fermacell.