Traditional screed generally consists of either a 1:3 or 1:4 cement to sand ratio which complies with BS 8204-1.It can be mixed with polypropylene fibres (PPF) for reinforcement or in some cases a D49 metal mesh is used instead of the PPF as reinforcement.
Generally, traditional screed dries at 1mm per day up to 40mm and anything thicker than 40mm dries at 0.5mm a day. Foot traffic – 24-48 hours. There are also additives that can be used to increase the drying time of the screed such TekcemTekscreed resulting in full traffic after 7 days. This allows other floor finishes being applied onto the screed sooner.
Traditional screed can be applied in many variations:
Floating is screed is most commonly used in residential properties as the screed is applied on top of a layer of thermal/acoustic insulation. The insulation is usually applied on to the DPM. Minimum thickness 75mm and 65mm is acceptable for domestic housing.
The screed layer is fully bonded to the substrate using a bonding agent or a primer. It is most commonly used in areas that will experience heavy loading. 25mm-40mm – can go up to 200mm
The screed layer is not bonded to the base, but instead it is applied to a Damp-Proof Membrane (DPM) or polythene, separating the screed from the concrete. 50mm-70mm – can go up to 200mm
MODIFIED SCREED (UFH)
Modified Screed (UFH)
This type of screed is applied over underfloor heating systems. 55mm – 200mm