The standard mix for pointing brickwork or stonework is typically 5 parts building sand to 1 part cement, along with a plasticiser added according to the manufacturer's instructions.
However, the ideal ratio can vary depending on the specific application and desired strength.
Here's a more detailed breakdown:
-
Standard Pointing Mix (General Use): 5 parts sand : 1 part cement : plasticiser
- This is suitable for most wall pointing applications. The plasticiser improves workability and reduces cracking.
-
Stronger Mix (Patio Slabs, Exposed Brickwork): 3 parts sand : 1 part cement : plasticiser
- A stronger mix is often preferred for areas exposed to more weathering or heavier use, such as patio slabs or exposed brickwork.
Why the Ratio Matters:
- Too much cement: Can lead to a rigid and brittle mortar that is prone to cracking. It can also shrink excessively, pulling away from the brick or stone.
- Too little cement: Creates a weak and crumbly mortar that will not effectively protect the brickwork from water penetration.
Important Considerations:
- Sand Type: Use a fine building sand (also known as soft sand) for pointing. Sharp sand (coarse sand) is not suitable.
- Plasticiser: Always use a plasticiser to improve the workability of the mortar and reduce the risk of shrinkage and cracking. Follow the manufacturer’s instructions for the correct dosage. If you are mixing by hand, use the maximum recommended amount of plasticiser.
- Water: Add water gradually until you achieve a workable consistency. The mortar should be firm but not too wet.
- Color Matching: Consider adding a pigment to the mix to match the existing mortar color.
- Trial and Error: It is always a good idea to test a small area first to ensure you are happy with the color and consistency of the mortar.
Example Table: Mix Ratios
| Application | Sand:Cement Ratio | Notes |
|---|---|---|
| General Wall Pointing | 5:1 | Standard mix, suitable for most applications. |
| Patio Slabs/Exposed Brickwork | 3:1 | Stronger mix for increased durability and weather resistance. |
In conclusion, while 5:1 is a generally accepted ratio, consider the environmental exposure and intended use of the pointing to determine if a stronger mix is necessary for your specific project.
