SBR Polymer Screed includes a synthetic polymer resin to give increased toughness and bond properties. Shrinkage and cracking is minimised, permeability is reduced and flexural strength is improved. This screed provides high performance at thinner sections and is ideal when normal thickness cannot be achieved.
Tarmac SBR Polymer Levelling Screed was developed by Tarmac to meet the increasing demand for factory produced cement sand levelling screed with the inclusion of a synthetic polymer resin to give increased toughness and bond properties. For new work, normal minimum screed thicknesses should be specified, but where this is not possible, e.g. in refurbishment work, where levels must be maintained, there is often a need for a thinner screed which must be well bonded to the base.
Where can SBR Polymer Screed be used?
Flooring solutions
SBR Polymer Screed is ideal to use for concrete ground floor slabs and other flooring applications.
Refurbishment and repair work
The properties of SBR Polymer Screed make it ideal for refurbishment and repair work.
Why use SBR Polymer Screed?
Additional info
One tonne of screed material will have an appropriate volume of 0.43 – 0.48m3. The table shows the approximate coverage area per tonne for a range of thicknesses.
|
Thickness (mm) |
Coverage area m2/tonne (approx) |
Thickness (mm) |
Coverage Area m2/tonne (approx) |
|
10 |
45.0 |
45 |
10.0 |
|
15 |
30.0 |
50 |
9.0 |
|
20 |
22.5 |
55 |
8.2 |
|
25 |
18.0 |
60 |
7.5 |
|
30 |
15.0 |
65 |
7.0 |
|
35 |
13.0 |
70 |
6.5 |
|
40 |
11.0 |
75 |
6.0 |
Bonded Construction (Minimum thickness 25mm) The bond between the base and levelling screed will depend on the thoroughness with which the base has been prepared. Scabbling to remove any weak surface layer and to expose the aggregate is strongly recommended. A bonding agent such as Tarmac SB Admixture can be used to obtain a good bond. The bonding agent should be used in a slurry with cement in place of the normal cement and water (3 volumes cement: 2 volumes Tarmac SB Admixture) and the screed is laid before the slurry dries or sets.
Unbonded Construction (Minimum thickness 50mm) When no bond is possible between levelling screed and base, the screed should be at least 50mm thick or, if containing heating pipes a minimum of 65mm thick.
Floating Screed (Minimum thickness 75mm / 65mm for light loading) A levelling screed that is laid on a compressible layer such as thermal or sound insulating material should be at least 65mm thick or, if containing heating pipes a minimum of 75mm thick. All conduits should be firmly fixed covered with suitable crack control mesh and given a minimum cover of 25mm. BS 8204-1 recommends that where possible pipes and conduits should not be laid within the thickness of a levelling screed.
Where Tarmac SBR Polymer Levelling Screed is laid on thermal or sound insulation boards, which are sufficiently rigid to enable the screed to be properly compacted, the minimum thickness to the Tarmac SBR Polymer Levelling Screed may be reduced to 55 mm.
Use of Tarmac SBR Polymer Levelling Screed for floating screeds helps to minimise the occurrence of cracking.
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