Bonded Screeds need to be laid onto a concrete base, and be bonded using an adhesive such as PVA, SBR or epoxy resin. SBR has approximately the same characteristics as PVA, but it is not water soluble after drying, and so is recommended around wet areas, such as swimming pools.
Un-bonded screeds are not bonded directly onto the concrete base, but are intentionally debonded with the use of a DPM (damp-proof membrane). The advantage is that any cracking from the sub-base is not carried through to the screed, drying times can be reduced by omitting the concrete drying time.
Floating Screeds are laid on insulation to provide an insulated floor area. All walls and pillars must be lined with edging foam or 20mm insulation, this will protect against shrinkage and cracking. This system is the most commonly used in house building, especially with underfloor heating systems.
Fast-drying screed such as Isocretes, use super-plasticisers to reduce the amount of water needed to make the screed mixture plyable, this in turn makes for a fast drying time as there is a higher cement to water ratio.
Fast-set screed such as a hydro rapid type screed rely on aluminium based cement to accelerate the setting process. This type of screed can have foot traffic after an hour or two, and is usually dry within 2 days. This type of system is expensive if used on large areas and it can only be site mixed.
Polymer modified screed is a standard cement mix with SBR added in large amounts to create a gluey screed. When set theses types of screed are resistant to water and other chemicals, they also allow floor screeds to be thinner than non-polymer modified screeds.
As well as traditional sand and cement screeds we can also offer fibrous screed, early strength screed, early fibrous strength screed and SBR rubber toughened screed, all in a range of grades from C5 to C30.(factory quality control)
Insulation, Damp Proof Membranes & Underfloor Heating
Laying of Insulation
Used in the floating screed system to insulate the sub floor, and is also common place for underfloor heating.
Laying of DPM (Damp Proof Membrane)
Used in the unbonded screed system, the advantage is that any sub-base cracking below the DPM will not carry through the screed.
Laying of Radon Gas Barriers
Radon Gas Barrier is used for the protection of buildings and occupiers from the ingress of gas, this is only used when building on gas contaminated land.
We design, supply and install a wide range of underfloor heating systems, including electric and water solutions with various heat outputs to suit your requirements.