Floor screed is composed of cementitious materials and sand blended based on a suitable mix design and applied to provide a leveled surface for the floor finish which is introduced to the surface of the floor screed.
So, floor screed is the base for the floor finish and greatly influences the performance of floor finish. In this article, different aspects of floor screed will be explored.
Fig.1: Details of Floor Screed
Fig.2: Floor Screed Construction
Following points regarding flooring screeds are discussed:
- Types of floor screed
- Floor screed materials
- What are the requirements that a floor screed should meet?
- Floor screeding procedure
- How can a successful screed floor be constructed?
Types of Floor Screed
There are different types of floor screed that is specified based on the requirements and applications and the functionality of the floor:
- Unbonded screed floor (Figure 3 and Figure 6)
- Bonded screed floor (Figure 3 and Figure 4)
- Floating screed floor (Figure 3 and Figure 5)
- Heated screed floor (Figure 3 and Figure 7)
Fig.3: Different Types of Floor Screeds; (A) Bonded Screed, (B) Floated Screed, (C) Unbonded Screed and (D) Heated Screed
Fig.4: Bonded Screed Floor
Fig.5: Floated Screed Floors
Fig.6: Unbonded Screed Floors
Fig.7: Heated Screed Floor
Materials for Floor Screed
Following are the materials used for the construction of floor screeds:
- Clean and sharp sand
- And occasionally additives are added to obtain specific properties. Polymer materials or metal mesh or glass are likely to be introduced to reinforce the screed.
The above components are adequately blended based on the prepared material proportions. If the thickness of the floor screed does not exceed 40mm, then the recommended mix is 1 Portland cement: 3 sands or 1 Portland cement: 4.5 sand.
However, 1 cement: 1.5fine sand: 3 coarse aggregate (10 mm maximum aggregate size) should be considered if the floor screed thickness is greater than 40mm.
It should be known that drying shrinkage gets reduced as the proportion of cement to sand is decreased.
The suitable amount of water should be specified to provide required workability since excessive water would reduce floor screed strength and inadequate water quantity lead to poor compaction.
What are the Requirements that a Floor Screed Should Meet?
Floor screeds should have the adequate thickness which is based on the screed type and application frequencies. Recommended floor screed thickness based on the type of the screed floor and the construction conditions are provided in Table-1.
- industrial utilization
- It should be solid and compact so as to provide satisfactory base for the floor finish
- It should be curried properly to prevent shrinkage and rapid drying which lead to cracks. So, it should undergo almost all shrinkage, which floor screed might experience, prior to applying floor finish. This will lead to preventing the initiation of cracks.
- Finally, floor screed surface should be flat and smooth.
Procedure of Floor Screeding
- Evaluate the surface of the base
- Estimate materials used for screeding
- Prepare the base
- Prepare the floor screed mixture
- Apply bonding agents such as water or bonding slurry
- Place the floor screed mixture
- Finally, properly cure the placed materials
How can a Successful Screed Floor be Constructed?
- Choose right and suitable screed contractor
- Select suitable screed floor type
- Produce right and suitable floor screed mixture
- Construct floor screed using appropriate and acceptable screed placement process
- Consider right approaches for floor screed protection