1. Cut away a square or rectangle patch large enough to embrace all of the damage, using a hammer and bolster.

When complete, cut in at the edges to provide a lip against which the repair mortar can tightly bond.

2. Follow this by scraping the exposed brick surface with your bolster to remove high spots and pieces of crumbling mortar.

3. To provide a good key for the mortar, chip at the exposed brickwork with a pick hammer or similar masonry tool.

4. Apply mortar to wall in an upward sweep. Force it well in as you do so and scrape away the excess. Let the first application settle and dry; apply topcoat in the same way as undercoat.

5. Use a timber straightedge to get the topcoat absolutely level with the surrounding wall; scrape diagonally or horizontally upwards.

6. Do the final smoothing with a wooden float - using a steel float may cause cement and water to rise to the surface, weakening the mix.

7. Finish by feathering the edges of the new patch into those of the surrounding render, using a damp cloth.

DIY Tips:
Use a piece of plastic to protect paving or walkways.

Rendering Mix
Roughcast or textured render
1 part cement : 4 sharp sand

Fine render
1 part cement : 4 sharp sand
Do not add too much cement as this will lead to surface cracking during drying.

Curing Method
Leave to dry for at least two days. The topcoat should only be applied once the undercoat has completely dried.

In hot weather, cover the drying mortar with plastic sheeting and regularly douse with water to allow gradual hardening.