This website uses cookies to ensure that we give you the best experience on our website.
By continuing to browse the site you are agreeing to our use of cookies. To find out more click here

Weber - Saint-Gobain

weber.floor flex

weber.floor flex

Product Benefits

weber.floor flex is a high-performance, fibre-modified, cement-based, self-smoothing, self-levelling, rapid-drying floor screed.

It is used for correcting surface irregularities on difficult surfaces, including wood, in interior situations.

Product Features

About this Product

High-performance, fibre-modified, self-smoothing, self-levelling renovation screed (up to 50 mm)

For levelling:

  • Cement screeds, concrete slabs and pre-cast elements
  • Floors with under-floor heating or under-tile warming
  • Wooden flooring (plywood and particle board panels)
  • Existing ceramic and rigid plastic tiles
  • Floating floors

Suitable for covering with:

  • Tiling
  • Flexible floor coverings
  • Parquet flooring
  • Certain floor paints

In situations that will be very humid, such as bathrooms, weber.sys protec tanking system may be applied over weber.floor flex.

Features and Benefits

  • Excellent levelling properties
  • Can built up to 50 mm
  • Rapid drying (light foot-traffic after 3 hours)
  • Improved bond to difficult substrates
  • Flexibility to absorb limited movement, e.g. under-floor heating and wood
  • Fibre modified for increased resilience


Not suitable for:
Exterior use
Floors with rising damp
Industrial areas
As a wearing surface

Technical Data

Technical Services

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) 722137
Fax: (01525) 718988

Sales Contact

Weber products are distributed throughout the UK through selected stockists and distributors. Please contact the relevant Customer Services Team below for all product orders and enquiries.

England and Wales:-

Tel: 08703 330070

Fax: 01525 718988

Scotland, Northern Ireland, Isle of Man, Republic of Ireland:-

Tel: 028 9335 2999

Fax: 028 9332 3232


Send or download the documents

You can either send the documents to an email address, or download it

Preparation & Application


Switch off any under-floor heating systems at least 24 hours before application.

Substrates should be completely dry, hard, rigid and clean. Remove any traces of paint, plaster or laitance or other unsound materials. Thoroughly remove all traces of dust by vacuuming. Fill any large deep holes and allow to dry. Localised holes, up to a total thickness of 50 mm can be filled with weber.floor flex.

Timber should be rigid and strong enough to support the expected load with minimum deflection, normally at least 18 mm thick of a flooring grade and ventilated beneath. Screw wood panels to joists at least every 200 – 300 mm to prevent movement and ensure that every board edge is adequately supported by its adjacent board or joists and noggins. Ensure that all joints and cavities in the substrate are protected to prevent leakage.

Priming with weber PR360 is recommended to improve adhesion, reduce air bubbles, improve the flow of the screed and prevent de-watering.

weber.floor 4945 fibre mesh should be used to reinforce weber.floor flex in critical areas. The mesh should be fixed to the substrate to prevent it floating to the surface during the application of the screed.


Do not mix if the temperature is outside of the range +5°C to +30°C.

Thoroughly mix with 5.25 litres of water per 25 kg bag using a slow speed electric mixer (500 rpm) for at least two minutes until a fluid, homogenous paste is obtained.

Allow to stand for 2 minutes and use within approximately 20 minutes. At higher temperatures this time will be reduced.


Pour the mix onto the floor and spread evenly with a steel trowel, spatula or spiked roller. Do not apply at thicknesses above 50 mm. The product will self-smooth and most trowel marks will disappear.

The minimum application thickness for wooden substrates is 10 mm.

At 15 – 20°C weber.floor flex will have set sufficiently hard in 2 – 4 hours to withstand light foot traffic. Laying of the floor covering can then commence within 24 hours. At lower temperatures and at thicknesses over 5 mm, these times are extended.

weber.floor flex is not intended as a wearing surface so the final finishing layer should be applied as soon as possible after drying has completed. If it is to be left for prolonged periods of time the surface should be suitably protected.

Allow for suitable expansion or control joints in screeds or slabs, by following them through the new topping.

Packaging, Health & Safety

Storage and Shelf Life

When stored unopened in a cool, dry place at temperatures above 5°C, shelf life is 6 months from date of manufacture.

Health and Safety

Contains cement (Contains chromium (VI). May produce an allergic reaction). Harmful by inhalation. Irritating to eyes and skin. Keep out of the reach of children. In case of contact with eyes, rinse immediately with plenty of water and seek medical help. After contact with skin, wash immediately with plenty of soap and water. Wear suitable protective clothing, gloves and eye/face protection.