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Weber Saint-Gobain - Official website of the company

webercem HB40

webercem HB40
webercem HB40

Product Benefits

  • Structural concrete repairs, particularly where high overhead build is required.
  • Repairs to bridge and highway structures.
  • Repairs to car park soffits, bridge decks and columns.

Acrylic-polymer modified, high build structural repair mortar:

Product Features

About this Product

webercem HB40 is a single-component, polymer-modified, high-build cementitious mortar, designed for structural concrete repairs. It requires only the addition of clean water to produce a lightweight, low-permeability, high-strength mortar for both soffit and vertical repair situations. The mortar is suitable for repairs to bridges and other structures as specified by the Department of Transport.

This product has been formulated to comply with the requirements of BS EN 1504-3 as an R3 mortar.

Features and Benefits

▲ Lightweight, low-density structural repair mortar which allows speedier completion of work ▲ High-build properties - up to 75mm vertically and 50 mm in a soffit repair, without formwork ▲ Unique shrinkage compensation system provides long-term dimensional stability ▲ Contains fibres and spray dried acrylic polymer ▲ Low permeability to water, carbon dioxide and chlorides ▲ Easy to apply, with excellent application properties ▲ This product has been formulated to comply with the requirements of BS EN 1504-3 as an R3 mortar ▲ Complies with Department of Transport Departmental Standard BD 27/86

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) 722110
Fax: (01525) 718988

Sales Contact

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: (01525) 722100
Fax: (01525) 718988


Product Datasheet

Material Safety Datasheet

Declaration of Performance (DoP)

Send or download the documents

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

Preparation & Application


Concrete substrates

Concrete substrates must be adequately prepared by use of scabbling, grit blasting, needle gunning or other means, as appropriate. Oil and grease must be removed by steam cleaning together with suitable detergent. Any contaminated concrete must be removed. All damaged concrete should be cut back to a sound surface and at least 15 mm behind any exposed reinforcement. New concrete must be at least 14 days old. Thoroughly saturate the concrete but remove excess water.

Steel substrates

These should be grit blasted to Swedish Standard SA 21/2 equivalent to BS 7079-A1 and degreased immediately prior to application. Where corrosion is absent, wire brushing to a clean, bright surface may be adequate. Care must be taken not to polish the rust. Apply a protective coating of webercem bondcoat as described below to act as a holding primer.

Note: Preparation of both concrete and steel must achieve a clean, sound, roughened surface.


Mixing of bonding slurry

Mix 2.5 volumes of webercem bondcoat powder to 1 volume of clean water. Mix vigorously to a brushable, slurry consistency. For detailed application instructions, see separate webercem bondcoat data sheet.

Mixing webercem HB40

A low-shear, forced-action mixer must be used, e.g. Mixal Mixer or Creteangle. Hand mixing the mortar is not recommended. Mix for 2 minutes from adding the powder to the water. Over mixing will entrain air and reduce compressive strength. Do not overmix. Water addition is 2.4 to 2.7 litres of clean water per 20 kg bag. Start at 2.4 litres and adjust as required upwards to 2.7 litres. Do not add more than 2.7 litres of water.


Priming of steel reinforcement

Apply one full, unbroken coat of webercem bondcoat, ensuring the back of the cleaned reinforcing bars are coated.

Priming of concrete substrate

Ensuring the prepared concrete substrate is saturated but surface damp, use a stiff brush to scrub the slurry well into the surface. Apply the mortar to the substrate whilst the bonding slurry is still tacky and compact well into place, ensuring no air is trapped. The minimum application thickness is 10 mm. Where very thick sections are required, multiple applications may be necessary. Intermediate surfaces should be scratched to give a good mechanical key. Successive applications require the use of webercem bondcoat.


If subsequent materials or coatings are to be applied, finish with a wooden or plastic float or sponge to present a lightly textured surface. Otherwise, finish with a steel float for a tightly closed surface.


Unless a levelling mortar, coating, inhibitor, sealer or other system is to be applied to the surface, cure immediately after finishing with a suitable membrane. Before application of a coating or a levelling mortar, cure the repairs by covering with closely-fitting polyethylene sheeting or use webertec latex as an intermediate curing membrane sprayed onto the repaired surfaces in a continuous film. webertec HB40 can be overcoated by the levelling mortar webercem fairing coat or one of the anti-carbonation coatings in the webercote range. Overcoating times are dependent on weather conditions. When cured, webercem HB40, and webercem bondcoat are stable to freeze/thaw conditions but, following good concreting practice, they should not be applied in freezing weather or onto frozen surfaces or at temperatures below 5°C.

Packaging, Health & Safety


webercem HB40 is supplied in 20 kg bags.

Coverage / Yield

webercem HB40 - Approximately 15.0 litres per 20 kg bag, i.e. 67 bags per m³ or 1.5 m² per bag at 10mm thickness.

webercem bondcoat - Approximately 5 kg per 1 m2.

Storage and Shelf Life

When stored unopened in a dry place at temperatures above 5°C, shelf life is 12 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.

For further information please refer to the Weber Safe Handling Guide.