Do not lose warranty on your floor: floor manufacturers’ recommendations

The floor must tolerate long years of walking and other impacts. Hence, manufacturers can even grant a 25-year warranty. Each warranty, however, has its limits.

So what should be kept in mind in order to ensure the durability of the floor, to keep your peace of mind, and to be sure about complicity with warranty terms? First and foremost, read the instructions which come with the floor’s packaging and strictly follow the assembly rules. The most important instructions given by major floor manufacturers come down to three basic issues:


The floor must be laid on a stable and level substrate with an admissible deviation of 2 mm along 200 cm. With laminated floors, the substrate must be dry, clean and feature suitable load-carrying capacity. Given that laminated floors are highly susceptible to moisture, we recommend measuring substrate moisture content by means of a carbide-based CM gauge. When no floor heating system is installed, substrate moisture content must not exceed 2% CM in the case of cement and 0.5% CM in the case of anhydrite. With a floor heating system, the abovementioned values must not exceed 1.8% CM and 0.3% CM respectively.

House-building teams use thousands of litres of water, which remain bound inside the ceilings and walls. Air moisture can also increase the water concentration in the floor. This is why suitable room temperature (+18 to +23 oC) must be ensured with simultaneous control of relative humidity (50–70%). Accurate measurement is extremely important when project implementation time has been significantly reduced and there is increased pressure for prompt completion. Yet the floor must dry.

Vapour barrier

Prior to the installation of panels on a mineral (cement or anhydrite) substrate, a special vapour barrier should be laid in order to protect the system from moisture. Vapour barriers should also be used for the purpose of laying panels over the floor heating system.

This layer is responsible for protection against moisture from the substrate. It may be made of a special vapour-proof membrane or an underlay with an integrated vapour barrier. To select a suitable vapour-proof membrane, forget its thickness and look instead at the SD rating: the higher the value, the better the protection of the floor from moisture. The minimum required SD value is > 75 m.
Once the substrate is ready, unfold the vapour-proof membrane with 20–30 cm overlap and seal it with moisture-resistant tape. The membrane must overlap the walls up to 3–4cm.
A faster and more reliable method involves the use of underlays with integrated vapour-suppressing film – “2-in-1” or “3-in-1” – which contain a self-adhesive layer to facilitate the bonding.



If well selected and well laid, panel underlays will extend floor durability and increase the user’s comfort. They contribute to the soundproofing of the panels and effectively protect panel locks from mechanical damage.

Manufacturers of panels require a stable and level substrate. Floor level differences cannot be eliminated by means of underlays, but some punctual unevennesses, i.e. minor defects, may be levelled with appropriate floor underlays. Such underlays may absorb, for example, small screed particles and make the surface smooth enough to lay the panels. This parameter is identified as PC and its value is expressed in [mm]. The thickest underlays can compensate for punctual unevennesses of up to 5 mm.

In heavily used rooms, the floor must be of the highest stability and durability. A good underlay whose load resistance is as high as practicable will perfectly absorb shocks and impacts while protecting the vulnerable panel locks. Load resistance is identified as CS and its value is expressed in [kPa].

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