Home Crochet baby clothesScreed thickness | Minimum and maximum thickness according to DIN

Screed thickness | Minimum and maximum thickness according to DIN

  • Important values
  • Screed thickness: an overview
    • Calcium sulphate fluid screed (CAF)
    • Calcium sulphate screed (CA)
    • Mastic asphalt (AS)
    • Synthetic resin screed (SR)
    • Magnesia screed (MS)
    • Cement screed (CT)
    • Bonded screeds

Screed is an important component that performs a variety of functions. In living spaces, screed is mainly used as a substrate for floor coverings and as an intermediate layer for pipes or underfloor heating. In the processing of the soil a distinction is made between different construction methods, but they have one thing in common: standardized thicknesses. The screed thickness is fixed in order to be able to guarantee load carrying capacity.

When laying screed numerous points must be taken into account. Since the screed is an important floor layer in living spaces, you must lay it exactly to counteract a phase shift. An essential value is the screed thickness, which is regulated according to the ISO standard DIN 18560. It defines the minimum thicknesses and maximum thicknesses that the installer and you will consult when laying screed. These guarantee the functioning of the screed ceiling and ensure that, for example, the underfloor heating can provide the desired heat. Especially in living rooms, the use of standardized thicknesses is a must, so you can pursue their function.

Important values

Since screed thicknesses are standardized, the information given in certain values, which help in the implementation. These would be:

1st type of screed: the type of screed indicates which type of screed it is. This information is important, because each of the six types of screed is effective in different thicknesses, which makes a distinction necessary. These are abbreviated, for example, CAF stands for calcium sulfate flow screed.

2. Bending tensile strength class (also known as hardness class): this specification describes the respective bending tensile strength class of the Estrichtypen. But the type of screed alone is not sufficient to determine the screed thickness, because each type has several hardness classes, which determine the respective tensile stress under load. These are indicated by a number and a letter (F and C) and are defined by the standard DIN EN 13813.

3. Minimum nominal thickness: the minimum nominal thickness is given in mm and describes the minimum height that a screed layer must have. These are completely standardized and must be adhered to.

4. Maximum thickness: the maximum thickness of the screed floors is also given in mm and is only set by the standard in a few cases, as you can see in the list below. When building a house a maximum thickness of 5.5 to 8 mm is common, but this value can vary greatly to the standardized units, from which you must pay attention.

5. Compressibility: the compressibility is given in c and is for residential areas a value of up to or equal to 5 mm, which is used in the list below. An exception is the mastic asphalt screed, which has a compressibility of up to or equal to 3 mm. This value describes the difference between the delivery thickness and the thickness under impact sound insulation, which is laid under the screed and thus has to endure a lot.

6. Surface load: the surface load is applied to vertical payloads acting on the ground. This means, for example, human movements as they occur normally throughout the day. In construction, there are several surface loads that must be taken into account. For living spaces, an area load of up to or equal to 2 kilonewtons (kN) per square meter is specified, which is used for all thicknesses in the list below.

Tip: no screed thicknesses are listed here for the heavy-duty screeds, ie industrial screeds. These are never used in your own home and in the hobby area and are therefore unimportant for you.

Screed thickness: an overview

Calcium sulphate fluid screed (CAF)

The following are the thicknesses for floating screeds on insulating layers:

  • F4: minimum nominal thickness up to or equal to 35 mm, no maximum thickness
  • F5: Minimum nominal thickness up to or equal to 35 mm, no maximum thickness
  • F7: Minimum nominal thickness up to or equal to 35 mm, no maximum thickness

Calcium sulphate screed (CA)

The following are the thicknesses for floating screeds on insulating layers:

  • F4: Minimum nominal thickness up to or equal to 45 mm, no maximum thickness
  • F5: Minimum nominal thickness up to or equal to 40 mm, no maximum thickness
  • F7: Minimum nominal thickness up to or equal to 35 mm, no maximum thickness

The minimum nominal thickness for screeds on separating layers is a maximum of 30 mm.

Mastic asphalt (AS)

The following are the thicknesses for floating screeds on insulating layers:

  • IC10: minimum nominal thickness up to or equal to 25 mm, no maximum thickness

The minimum nominal thickness for screeds on separating layers is a maximum of 25 mm.

Synthetic resin screed (SR)

The following are the thicknesses for floating screeds on insulating layers:

  • F7: Minimum nominal thickness up to or equal to 35 mm, no maximum thickness
  • F10: minimum nominal thickness up to or equal to 30 mm, no maximum thickness

The minimum nominal thickness for screeds on separating layers is a maximum of 15 mm.

Magnesia screed (MS)

The following are the thicknesses for floating screeds on insulating layers:

  • F4: Minimum nominal thickness up to or equal to 45 mm, no maximum thickness
  • F5: Minimum nominal thickness up to or equal to 40 mm, no maximum thickness
  • F7: Minimum nominal thickness up to or equal to 35 mm, no maximum thickness

The minimum nominal thickness for screeds on separating layers is a maximum of 30 mm.

Cement screed (CT)

The following are the thicknesses for floating screeds on insulating layers:

  • F4: Minimum nominal thickness up to or equal to 45 mm, no maximum thickness
  • F5: Minimum nominal thickness up to or equal to 40 mm, no maximum thickness

The minimum nominal thickness for screeds on separating layers is a maximum of 45 mm.

Bonded screeds

Composite screeds are standardized as single screeds with a maximum thickness. The reason for this is the application, because the screed is applied directly to the subfloor compared to the other species. This has a corresponding effect on the screed thickness. Following the values:

  • Calcium sulphate screed: without minimum nominal thickness, maximum thickness up to 50 mm
  • Mastic asphalt screed: without minimum nominal thickness, maximum thickness up to 40 m
  • Synthetic resin screed: without minimum nominal thickness, maximum thickness up to 50 mm
  • Magnesia screed: without minimum nominal thickness, maximum thickness up to 50 mm
  • Cement screed: without minimum nominal thickness, maximum thickness up to 50 mm
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