Cempatch LS
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High build, fibre reinforced, high strength cementitious repair mortar

Cempatch S is a one component polymer modified and fibre reinforced repair mortar. Cempatch S is a blend of dry powders, selected aggregates and fibres which when mixed with water produces a thixotropic mortar suitable for vertical and overhead application


Cempatch S is designed for repair of all types of structural concrete where high strength and extremely low shrinkage properties are required.

Materials Supplied

20 kg or 25 kg polythene-lined paper sacks.


A 20 kg sack using 3.5 – 4 litres of clean water will yield approx. 11.5 litres.

A 25 kg sack using 4.5 – 5 litres of clean water will yield approx. 14.5 litres.

A 20 kg sack of Cempatch S will cover approximately 0.6 m2 at 20 mm thickness.

A 25 kg sack of Cempatch S will cover approximately 0.75 m2 at 20 mm thickness.


Protect from frost and store under dry warehouse conditions at a temperature between 5oC and 30oC.

Shelf Life

12 months in unopened bags and stored under good condition.


Substrates should be mechanically prepared by wire brush, hammering, grit-blasting, steam cleaning etc., to produce a clean, aggregate exposed finish, free from contaminants that may prevent adhesion. Edges must be cut back to a minimum depth of 10mm surrounding the repair to allow the repair area to be ‘toed-in’.

At joint detail it is recommended that the substrate be cut back to a depth of around 25mm. Feather edging is not recommended and should be avoided.

Any exposed steel should be completely uncovered and abraded to a bright finish (SA 2½) after removing any rust scale or corrosion products. Where corrosion has occurred due to chloride attack the steel should be high pressure washed and grit blasted.
The temperature of the repair area must be maintained above 5°C throughout the application and drying of Cempatch S.

All cleaned areas of the reinforcement should be treated with 1 - 2 coats of Repcoat ZR2 - zinc-enriched epoxy coating. The areas to be restored with Cempatch S must be soaked with clean water before application. Excess water must be removed. Apply 1 coat of Cempatch Primer. Cempatch Primer must still be tacky when laying
on top of Cempatch S.

Cempatch S should be mixed using a forced action mixer such as a Crete angle, or a mechanically powered mixer or drill fitted with suitable paddle should be used. Slowly add the contents of a 20 kg sack to 3.5 - 4.0 litres of clean potable water depending on consistency required (for the 25 kg sack, 4.5 – 5 litres of water are needed).
Mix for approximately 3-5 minutes, until the mixture is homogeneous.

Cempatch S can be applied by trowel or hand. The mixed mortar should be applied using firm pressure to fully compact the mortar to ensure good adhesion with the steel reinforcements and the substrate. Finishing and leveling should be carried out initially by wooden or plastic float. Final finishing should be carried out using
steel float.
Wash tools with water immediately after use.

Once Cempatch S has achieved final set (after approximately 30 minutes) use appropriate curing methods such as Setseal 6 curing membrane or polythene sheeting.


Do not place when the substrate temperature is below 5°C or when the ambient temperature is 10°C and falling.
Protect from frost.
Do not exceed the maximum recommended water content per sack and only use clean potable water.

Cempatch S contains cement, which is alkaline and may cause skin irritation. Please refer to the relevant Health and Safety Data Sheet for detailed information.


This data sheet is for general guidance purposes only and may contain information that is inappropriate for certain conditions of use. Accordingly, all recommendations and suggestions are made without guarantee. Further information is available from our Technical Services Department.

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Don Construction Products Ltd.

Hawthorn House, Helions Bumpstead Road,
Haverhill, Suffolk, CB9 7AA, United Kingdom
Tel: +44 (0) 1440 766360 
Fax: +44 (0) 1440 768897

Email: info@dcp-int.co.uk
Email: stephen.bird@dcp-int.com
Email: tom.emery@dcp-int.com