Summary

Mortar and concrete mixes vary according to their intended 
use. The following steps detail essential information for 
achieving the perfect mix:

	1	About brickwork
	2	About mortar
	3	Mortar mixes for brickwork
	4	Mortar mixes for concrete blocks
	5	Mortar mixes for rendering
	6	About sand and aggregate
	7	Concrete mixes
	8	Potential problems
	9	About cement additives

	
Tools
Portland cement, ordinary building sand, water, plasticiser, 
sharp sand, soft sand, coarse aggregate, ballast.	

Step 1 - About brickwork
For calculations of area covered by brickwork include the 
mortar. An easy rule of thumb is you need 60 bricks per 
square metre of wall that is half a brick thick.

Step 2 - About mortar 
Premixed bags of mortar are available from your local 
hardware store. A typical bag usually contains enough 
for 40 bricks. For larger projects it may well be worth 
buying the materials individually and mixing it yourself. 
The constituents of mortar are Portland cement, ordinary 
building sand, water and a plasticiser.

Step 3 - Mortar mixes for brickwork
Please refer to the table, in the task, 'Measuring Building 
Materials'for more information on the recommended 
proportions of cement and sand required for various 
types of brickwork.

Step 4 - Mortar Mixes for Concrete Blocks
Please refer to the table, in the task, 'Measuring Building 
Materials' for more information on the recommended 
proportions of cement and sand required for various 
uses of concrete blocks.

Step 5 - Mortar mixes for rendering
Please refer to the table, in the task, 'Measuring Building 
Materials'for more information on rendering 
different materials.

Step 6 - Sand and aggregate
The sizes and shapes of their constituent particles form 
the basis of the grade for types of sand and aggregate. 
Sharp sand is used in making concrete. Soft sand is used 
for mortar. Coarse aggregate is crushed stone with a 
diameter of between 5-20mm and used in making concrete 
Ballast is a mixture of coarse aggregate with sharp sand.

Step 7 - Concrete mixes
Concrete is made up from Portland cement, sharp sand and 
coarse aggregate. The quantities involved are dependant 
on their use. Please refer to the table, in the task, 
'Measuring Building Materials' for information.

Step 8 - Potential problems
Cement whilst being mixed is quite unstable. It can shrink 
during the drying period causing cracks or it can become too 
rigid. Too much water will weaken it. In hot weather it can 
dry too quickly and in cold weather too slowly. No standard 
mix is waterproof and pores can develop during the drying 
process, which will make it susceptible to frost damage 
later.

Step 9 - About cement additives
Various additives are available to combat these problems and 
give mixtures greater flexibility and strength. They can make 
the mixes gain greater protection against water, which is 
useful for rendering. They can also alter drying times and 
even harden the surface for old concrete. Colourants are 
also available.