Screed-free floor systems offer a modern and lightweight alternative to conventional screed. In contrast to construction site screeds, screed-free floor systems are delivered to the construction site and laid as finished panels. The drying phase on the construction site is eliminated, no large amounts of moisture are introduced into the building and the flooring can be laid more quickly. They are highly resilient - despite the low installation heights, which are particularly advantageous during renovations. Due to the installation without a drying phase, the systems are usually immediately accessible, and the floor covering can be laid without long waiting times.
This bauwion knowledge page covers the topic of "screed-free flooring systems". One advantage of screed-free flooring systems over conventional construction site screeds is the significantly reduced waiting time until they are ready for covering. In addition, the dry installation leads to a lower moisture load on the building. Another advantage is the low construction heights and a lower weight per unit, which can be a decisive advantage, especially when renovating old buildings. In combination with underfloor heating, the smaller mass leads to less inertia of the heating surfaces and thus also to faster heating. In this way, individual needs-based control can contribute to economical energy consumption.
Installation methods: The processing and installation of screed-free floor systems is not regulated by standards, but can be found in the respective manufacturer's specifications.
Sound insulation and thermal insulation: Meeting the requirements for sound insulation and/or thermal insulation are among the essential tasks of a floor structure. In the absence of introduced technical rules, it is necessary to check whether the requirements are complied with on the basis of the technical documents of the respective manufacturer and transferred to the specific application. Sample structures with the respective sound insulation and thermal insulation values are available on the manufacturers' websites. Basically, the following can be said:
If there are increased requirements for impact sound and thermal insulation at the same time, two different insulation layers are arranged below the respective material in screed-free systems with wood-based panel and chipboard, similar to construction site screeds, with the impact sound insulation being directly below the screed-free layer. Insulation layers laminated to the elements at the factory have an economic advantage due to the installation in a single operation.
Fire protection: The class of fire behaviour is specified by the manufacturer. For products that have already been on the market for a longer period of time, this is done in accordance with DIN 4102-1, and for products approved from 01.01.2002 onwards in accordance with DIN EN 13501-1.
the construction of the subsoil: The subsoil must meet the requirements specified in terms of load-bearing capacity, fire protection, dryness, evenness and planned floor construction height. Further specifications of the manufacturer on the type and condition of the substrate must be observed, such as the basic suitability and the maximum permissible deflection of wooden planks for the selected further structure. In the case of reinforced concrete ceilings, a separating film, e.g. a 0.2 mm thick PE film, overlapping at the joints by at least 20 cm, must be arranged below the floor structure, which must be led up to the upper edge of the covering on rising components, e.g. walls. In the case of moisture-stressed floor slabs in the ground, waterproofing in accordance with DIN 18533 must be carried out before further floor construction. In wet rooms, waterproofing in accordance with DIN 18534 is required above the floor system.
If the required thermal and impact sound insulation is not achieved by the system itself, as is the case with wood-based panel and chipboard without laminated insulation, the corresponding additional functional layers required must be arranged below the floor system.
Note: Since screed-free floor systems are predominantly unregulated building products, the technical instructions of the manufacturers are of particular importance, e.g. in leaflets or in the usability certificate.
DIN 4108-4 Thermal insulation and energy saving in buildings - Part 4: Thermal and moisture protection design values
DIN 18340 VOB Procurement and Contract Regulations for Construction Services - Part C: General Technical Contract Conditions for Construction Services (ATV) - Drywall construction work
DIN EN 13162 Thermal insulation materials for buildings - Factory-made products made of mineral wool (MW) - Specification
DIN EN 13163 Thermal Insulation Products for Buildings - Factory Made Products of Expanded Polystyrene (EPS) - Specification
DIN EN 13165 Thermal Insulation Products for Buildings - Factory Made Products of Rigid Polyurethane Foam (PU) - Specification
DIN EN 13171 Thermal Insulation Products for Buildings - Factory Made Products of Wood Fibres (WF) - Specification
ZDB leaflet Pipes, cables and cable ducts on raw ceilings - Notes for screed layers and planners, Publisher: Bundesverband Estrich und Belag e.V. (BEB); Central Association of the German Construction Industry (ZDB), as of 08/2003
Source: bauwion
