Having gotten the basic concepts of DIY BRICKLAYING under your belt, you will be keen to start work on your first project. However, if you want to save time and money, there will be a few more things you will need to understand if your DIY BRICKLAYING project is to be truly successful.
It will be obvious that before you can start any project, you will need to work out the quantity of materials that will be required. It is important that you make an accurate assessment of the materials required for your project.
In the first instance, you will need to ‘cost’ the job. Whether you are undertaking a DIY BRICKLAYING project or employing someone else to lay the bricks, it is important to have an accurate idea of the costs that you are likely to incur. If you want the project to run smoothly, you will also need to order the materials in advance. (See my article on PLANNING A DIY PROJECT).
If you over estimate and order more materials than required, it is unlikely your merchant will take any surplus off your hands. If they do, it is likely to cost you a restocking fee. Then you have the issue of disposal or storage of the surplus materials. What do you do with a hundred spare bricks or blocks?
On the other hand, if you do not order enough materials, you will be subject to the whims of your merchant or supplier which could result in long, costly delays. This can be a major headache especially if your materials are not held in stock or were a special order. The advantages of bulk purchasing are also likely to be lost. The most problematic issue will be of color matching. Bricks from a different ‘batch’ form the kiln will vary in color. This can be really striking when the wall is completed and you stand back to look. It can totally ruin the visual effect of good workmanship and quality materials if supposedly ‘matching’ bricks do not match. It can all be very frustrating!
So, how much material do you need, and what materials do you need?
Clearly, you will know how tall and how long a wall is, but how many bricks will be needed is another thing. What about the mortar between the bricks – you will need to estimate this too?
As bricks are mainly made from clay, they are not a precise artefact. Sizes will vary slightly depending on the amount of moisture in the clay or the amount of time the brick has spent in the kiln.
For ease of calculation the nominal size of a brick is 215mm x 102.5mm x 65mm.
The mortar joint is nominally 10mm thick both horizontally and vertically. This makes the nominal size of a brick for calculation purposes 225mm x 102.5mm x 75mm (9″ x 4″ x 3″).
The long face of the brick is called the ‘stretcher’ and the end of the brick is the ‘header’.
In order to calculate the number of bricks required per meter, first find out the area of brickwork. Then decide on the ‘bond’ of the brickwork. The most common bond for standard brick walls is ‘stretcher’ bond. As a guide you should allow 60 bricks per square meter for the building of a single skin wall. This is known as a half brick wall. For a two skin cavity wall, you will need 120 bricks per square meter. Obvious isn’t it?
If you intend constructing a one brick thick solid wall, again you should allow for 120 bricks per square meter.
None of these figures allow for wastage or breakage, so it is a good idea to add a few extra bricks to the order to make certain that you do not run short. Normally around 10% extra should be sufficient.
The next question you will need to answer is how much mortar will I need? Once again the ‘rule of thumb’ answer is 25kg of dry mortar mix to 25 bricks. For smaller DIY BRICKLAYING jobs, dry ready mixed mortar can be bought in 25kg bags.
This will not be economic for the larger project. It will be more economic to bulk buy sand and mortar. Most bricklayers will mix sand and cement in a ½ cubic metre cement mixer. Here we move into the realms of BRICKLAYING folklore. The rule of thumb is a ‘½ bag mix’. This is half a 25kg bag of cement to 30 ‘shovels’ of sand. This approximates to a 1:5 mortar mix.
In fact, to lay say 1000 bricks (= 16.5 square meters) as a single skin wall, approximately .3 cubic metres of mortar will be needed. You can either use the ‘rule of thumb’ or calculate your quantities on the above basis.
For solid block work as a single skin wall, use 10 blocks per squared meter for your calculations. The blocks nominally measure 450mm x 215mm x 102.5mm. You will need 25Kg of dry mortar mix per 5 blocks.
Remember All calculations and quantities given here are approximate and the information supplied should be used for a guide only.
When working on a building site, a good bricklayer’s labourer is highly regarded, as the perfect mortar mix is important for good bricklaying. It is important that the ‘mix’ is just the right consistency. For 2.5 KG of dry mortar mix about 2.5 litres of water will be required. Water should be added first in sufficient quality to allow it to be absorbed by the mix, then it should be added little by little until the mix has a consistency of butter. This should allow it to slip easily from the shovel but firm enough for the sides not to collapse when a hollow is made in the centre of the mix.
Do not allow mortar to hang around unused for too long. Mortar should generally be used within two hours of mixing, so only mix sufficient to be used within that time.
If the mortar does ‘go off’ – do not ‘knock’ the mix back. The best thing to do is dump the mortar and mix up a fresh batch.
You can find out more about DIY BRICKLAYING in our next article ‘MORE ABOUT DIY BRICKLAYING II’