• Conbextra GP 25kg

Conbextra GP 25kg

SKU: 002cgp

£9.87 Ex Vat

Conbextra GP 25kg

£9.87 Ex Vat


Fosroc Conbextra-GP is a high-flow, non-shrink, cementitious grout which conforms to the requirements of BS EN 1504-3 Class R4 and BS EN 1504-6. It is suitable for use in gaps from 10mm to 75mm. This cementitious grout is ideal for the anchoring of reinforcing steel bars and some other uses include:

- stanchion base plates
- the joints between pre-cast concrete panels
- installing tie bars
- for grouting purposes when there's restricted pouring accessibility
- instead of dry packs using a trowelling consistency mix

Cobextra-GP is supplied in pre-bagged condition and should be mixed with clean water in order to reach the required consistency.

Conbextra-GP is supplied as a ready for use dry powder and needs mixing with clean water in controlled amounts. For a flowable grout mix between 4 and 4.5 litres of water will be required per 25kg of compound. For a mix that is to be applied by trowel, between 3.4 and 3.6 litres of water is required. Ideally, use a powered grout mixer to achieve the best results.

The product is suitable for gaps with a maximum width of 75mm and should be in place within 20 minutes of mixing, for best results. Conbextra-TS grout is available for grouting gaps wider than 75mm. 

Prior to using this product all surfaces should be clean and dry and free from any adherent materials, such as grease or oil. All surfaces to be treated should be flooded with water for a minimum of two hours before the compound is applied. After flooding the area to be grouted, users should thoroughly dry the area off. 

Once in situ, the grout has a compressive strength of more than 40 MPa after seven days, rising to 60 MPa after 28 days.

All manufacturer recommendations for storage and handling conditions for this product should be followed to achieve best results. And, users should also ensure recommended mixing instructions and application information is followed.

Just some of the advantages of this product include:

  • Non-shrink
  • High strength
  • Chloride free
  • Can be used at flowable or trowelable consistency


When mixed and in a "plastic" stage, the grout exhibits volumetric expansion of up to 1%, due to chemical gaseous reactions. 

Conbextra-GP consists of blended Portland cements, together with chemical additives and graded fillers. The fillers ensure that a free flowing grout is obtained, with no risks of bleeding or segregation.