Fosroc Conbextra HF

Non Hazardous
A high-flow, non-shrink, cementitious grout. Class R4.
Available in 20x 25 Kg bags (1/2 Pallet) and 40x 25 Kg bags (Full pallet)
From £512.75 £427.29
In stock
Only %1 left
Product Description

Fosroc Conbextra HF is a high-flow, non-shrink, cementitious grout conforming to the requirements of BSEN 1504 -3 Class R4 and BS EN 1504-6: Anchoring of reinforcing steel bar.

Best Uses

Fosroc Conbextra HF is used for free flow, non-shrink, cementitious grouting of gap thicknesses 10 to 100 mm. It's advantages include that it is non-shrink, highly flowable, chloride free and is suitable for pumping. Conbextra HF's recommended applications include:

  • Large stanchion baseplates
  • Joints between pre-cast concrete panels
  • Pumped grouting applications
  • Grouting applications where pouring access is restricted
  • Anchoring of reinforcing steel bars
  • Installation of tie bars


Conbextra HF is supplied as a ready to use dry powder. The addition of a controlled amount of clean water produces a freeflowing grout for gap thicknesses up to 100 mm. In addition the low water requirement ensures high early strength and long-term durability. Conbextra HF is a blend of Portland cements, graded fillers and chemical additives. The filler grading produces a highly flowable grout which will not segregate or bleed.

Full application instructions can be found on the product data sheet.

Technical Details


  • London Underground Approved: LUL APR No. 2190
  • Conbextra HF complies with LU Standard 1-085 ‘Fire Safety Performance of Materials’.
  • Conbextra HF complies with classification R4 according to BS EN 1504-3.
  • Conbextra HF complies with the requirements of BS EN 1504-6 : Anchoring of reinforced steel bar.
  • Conbextra HF conforms fully to U.S. Corps of Engineers Specification for non-shrink grout CRD-C621-82A and ASTM C1107-91 (Type C).

Technical Info

Components: Single Pack
Type: Cementitious Grout
Stock Colours: Grey
Tintable: No
Application Method: For best results a mechanically powered grout mixer should be used.
Theoretical Coverage: The approximate yield per 25 kg bag is 13.25 Litres Flowable and 13.5 Litres Fluid
Water Addition Per Bag: 4.5 Litres per 25 Kg bag Flowable and 4.8 Litres per 25 Kg bag Fluid
Compressive Strength:

EN 12190:1999. Class R4 > 45 MPa.

1 Day at 20°C = 22 MPa
7 Days at 20°C = 55 MPa
28 Days at 20°C = 70 MPa

Minimum Thickness: 10mm
Maximum Thickness: 100mm
Placing: Place the grout within 20 minutes of mixing to gain the full benefit of the expansion process.
Cleaner / Thinner: Conbextra HF should be removed from tools and equipment with clean water immediately after use. Cured material can be removed mechanically, or with Fosroc Acid Etch.
Shelf Life: 12 months if kept in a dry store in sealed bags. If stored in high temperature and high humidity locations the shelf life may be reduced to less than 6 months.
Packaging: Available in 20x 25 Kg bags (1/2 Pallet) and 40x 25 Kg bags (Full pallet)

For best results a mechanically powered grout mixer should be used.

The manufacturers data sheets are available for download from this website. It is your responsibility to read and understand all aspects of the data sheets before you place an order and prior to application. Please pay special attention to the preparation, mixing and application temperatures of the product, cleaning of substrate and environmental factors such as temperature, rain etc. Quoted coverage rates are based on the manufacturers theoretical rates and may vary depending upon substrates absorption, texture and application. We always recommend a test is carried out to ensure suitability.

Customer further agrees that Promain have no liability for any errors or omissions contained within the Product Data Sheets and are not liable for failure due to misapplication or inadequate substrate cleaning and preparation. For more information please refer to our Terms & Conditions.

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