weber.floor 4490 alpha screed 

Calcium Sulphate screed.

weber maxit floor 4490 Alpha screed is a pumpable, high-quality screed material based on calcium sulphate. It is supplied as a pre-blended dry powder and is designed for application at thicknesses of between 20 and 50mm. The system has been used extensisvely across Europe and complies with CUR-Recommondation 62, Levelling screeds with Calcium Sulphate as a binding agent in The Netherlands.

weber maxit floor 4490 Alpha screed is suitable for floors in homes, offices, public building and places exposed to similar loads. weber maxit floor 4490 Alpha screed may be applied as a levelling screed directly onto a load bearing floor, unbonded screeds on a seperating barrier, as a floating floor and may be used in conjunction with underfloor heating or cavity floors. weber maxit floor 4490 Alpha screed should be covered with a floor finish such as tiles, linoleum, parquet, cork or carpet. If a cement based adhesive or smoothing compound is required the surface of the Alpha screed must first be sealed, using the appropriate sealer.

• pumpable
• easy workability
• suitable for underfloor heating
• reduced drying time
• can be used as an underlayment in wet areas
• smooth finish

Light ventilation in the work area is necessary but windows and openings must be closed sufficiently to avoid draughts during and after application. Indoor and floor temperature must exceed +10C during and after application and one week after that. The relative humidity of the ambient air must not fall below 50%

weber maxit floor 4490 Alpha screed is designed for use as a bonded thick levelling screed on concrete. In addition it can also be applied as a floating screed over thermal or acoustic insulation, or as an unbonded screed on top of a plastic membrane.

The substrate should be clean, dry, free of dust, grease and other impurities that might prevent adhesion. If it a large area the surface should be treated by mechanical preperation by grinding or shot blasting. The surface strength of the substrate has to be at least 0.5MPa (N/mm²). the substrate is vacuum-cleaned and primed with weber.floor 4716 dispersion primer according to Weber's substrate recommondations. Dry and very porous substrates must be treated twice. If weber maxit floor 4490 Alpha screed is to be applied on plastic sheeting or as a flaoting floor, a gap of minimum 8mm should be formed around the perimeter (walls, columns, etc.) 

weber maxit floor 4490 Alpha screed should be mixed with 3.5 litres of water per 25kg bag, or 14% (m/m) of dry powder. Do not exceed the recommended quantities as too much water leads to a reduction in the overall strength of the cured material. Mixing time, if using a hand held drill and paddle, is 2 minutes. Do not mix more material than can be laid in 20 minutes. A suitable mixing pump system, approved by Weber, should be used for mechanical mixing. The best temperature for mixing is between 10-20C

Drill with paddle mixer (for small areas)

m-tec Duomix 2000

m-tec PD 100

Silo + SMP

Pumping is carried out in sections so that a wet edge is maintained. A wide steel 'wobble' bar is used to assist the levelling process. When applied bonded the minimum thickness of weber maxit floor 4490 Alpha screed should be 20mm, over underfloor heating this should be a minimum of 25mm over the pipes.

6 months under dry conditions

Weber's Customer Services Department has a team of experienced advisors available to provide on-site advice both at the specification stage and during application. Detailed specifications can be provided for specific projects or more general works. Site visits and on-site demonstrations can be arranged on request.

Technical helpline
Tel: (01525) 722110
Fax: (01525) 718988

Weber products are distributed throughout the UK through selected stockists and distributors. For UK sales enquiries and overseas projects, contact Weber's Sales office.

Sales office
Tel: 08703 330070 (press 1 for sales)                                                            Fax: (01525) 718988