Screed is an extra layer which acts as a substrate for your actual floor covering and is used for levelling the uneven floor structures, providing a flawless, flatter, and smooth finish. It is also popularly used as a sub-base for floors to install underfloor heating, retaining its pipes efficiently.
In this guide, you will learn about the advantages of floor screed, thickness of different types of floor screed, and the factors which affect its thickness. Moreover, you can also get information about the importance of considering floor screed thickness.
Advantages of Floor Screed
Floor screed is a mixture which is applied as a top layer over concrete or any other base, adding an aesthetic touch and insulation to your property. The benefits of using floor screed include:
- Durability
- Soundproofing
- High-Quality Finish
- Even Floor Surfaces
- Enhanced Thermal Quality
Thickness of Floor Screed Based on Its Type
The optimum maximum and minimum thickness of the screed is based on its intended purpose with different limitations for all screed types, such as:
Bonded Screed
This screed is bonded to the substrate directly.
Minimum Thickness
- Bonding a screed to the substrate directly using a bonding agent or primer (1mm to 2mm).
- Traditional sand and cement screed (40mm).
- Cement screed and modified sand (10mm).
Maximum Thickness
- Using a smoothing agent (10mm).
- Modified sand and cement screed (150mm to 200mm).
- Traditional sand and cement screed (150mm to 200mm).
Unbounded Screed
This type of screed is installed separately from the substrate with a membrane between them.
Minimum Thickness
- Unbounded smoothing agent (50mm).
- Modified sand and cement (35mm).
- Calcium sulphate flowing screed (15mm to 30mm).
- Traditional sand and unbounded cement (50mm).
Maximum Thickness
- Calcium sulphate (80mm).
- Modified sand and cement (infinite)
- Traditional sand and cement (infinite)
Floating Screed
This type of screed is separated from the substrate with acoustic or thermal insulation between them.
Thickness
- Calcium sulphate flowing screed for domestic use (35mm).
- Calcium sulphate flowing screed for commercial purposes (40mm).
- Modified sand and cement (35mm).
- Traditional sand and cement for domestic uses (65mm).
- Traditional sand and cement for commercial uses (75mm).
Factors Affecting Floor Screed Thickness
The following are different factors which affect floor screed thickness:
- Type of Screed
- Underfloor Heating
- Substrate Condition
- Purpose of the Floor
- Load Bearing Capacity
Importance of Thickness for Floor Screed
The floor screed’s depth should be within the recommended limits because a too-thin screed can crack or get damaged with screed delamination. On the other hand, a too thick floor screed can result in more bleed water and a weak and brittle surface that must be ground down.