weberfloor fibre rapid 4320

Prepare:

The surface strength of the substrate must be greater than 1N/mm².

It is essential the substrate is suitably prepared and primed with weberfloor 4716 primer prior to installing the Weber floor screed.

The substrate should be clean, free from dust, grease and other impurities that might prevent adhesion.

Walls and any upstands (pillars, columns etc) should be isolated with 10 x 100mm foam.

Large irregularities in the substrate (>50m) should be filled in with a application of weberfloor base rapid 4360, this should be allowed to harden and then primed before application of weberfloor fibre rapid 4320 can begin.

Holes and leaks in the substrate should be sealed. The substrate should be vacuum cleaned, prepared and primed with weberfloor 4716 primer according to the instructions on the data sheet.

Priming improves the screed’s adhesion to the substrate and prevents the formation of air bubbles and dewatering of the screed. Priming also improves the flow properties of the screed. Dry and very porous substrates (cast-in-situ concrete floors) may need to be treated twice. If the screed is applied in more than one layer, each layer must be primed.

Mix:

weberfloor fibre rapid 4320 is mixed with clean water using an automatic screed mixer approved by Weber. The material is mixed with 20% water, which corresponds to 5.0 litres per 25kg bag. It is important to add only the specified amount of water as excess water will reduce strength, increase shrinkage and encourage segregation. Whilst mixing, the water content should be checked continuously by the flow ring test to ensure that the material is correctly mixed and free from separation and lumps of powder. The flow rate should be between 220-235mm . Conversely, reduced water content increases viscosity. The temperature of the mix should ideally be between +15°C and +20°C. For manual mixing thoroughly mix using a slow speed electric mixer (500 rpm) for at least two minutes. Allow to stand for 2 minutes.

Apply:

Light ventilation in the working area is necessary but windows and door openings must be closed sufficiently to avoid draughts during and for 3 days after application.

During application, and for at least 1 week afterwards, the substrate and ambient temperature should not fall below +10°C or rise above +25°C. The relative humidity of the substrate must be <95%. To achieve the best finish, the floor area should be divided into bays of 6 to 8 metres depending on pump capacity and application thickness. weberfloor 4965 barrier foam should be used to form bays and stop ends. Pumping is carried out in sections so that a new section is pumped as quickly as possible and to maintain a wet edge. A wide flat spatula or wobble bar should be used to assist the self-levelling process.

In addition to solid bonded substrates weberfloor fibre rapid 4320 can be applied to a range of other substrates including flooring grade insulation boards, timber floors, underfloor heating and bitumen. For old and estab