This guide tells you how to mix mortar for bricklaying to a ratio of 5 parts sand, to 1 part cement. But first it is important to explain some basics about mortar.
What is Mortar?
Mortar is a versatile building material. Its main ingredients are cement, fine sand and water. Once water is added to the cement and sand mix, it then starts to harden over time, also known as curing. Mortar is not as strong as concrete, but very ideal for holding bricks together. Some people add what’s known as a plastisizer to mortar.
What is a plastisizer?
A plastisizer is a liquid that helps improve the properties of your mortar mix, such as the work-ability and durability. It works by introducing tiny bubbles of air into your mixture, and can also react chemically with your mixture to reduce the amount of water during the cure. A lot of tradesmen believe fairy liquid is a good replacement due to its bubble like properties. But we would never recommend fairy liquid as a plastisizer. This is because plastiziser is designed for mortar use only, and thoroughly tested on mortar. Fairly liquid is not designed for mortar use, which means the bubbles it creates, and its chemical properties are not beneficial to the mix.
Type of Mortar we will be Creating
We are going to mix mortar for bricklaying to a ratio of 1 to 5. This is considered the standard ratio for most DIY jobs. If you require a stronger mortar mix, then a ratio of 1:4 should be used.
Builders (or soft) Sand
2 X Builders Buckets
Cement / Mortar Mixer
Calculate Sand & Cement Quantities
Below shows you a way to calculate how much sand and cement you will need to complete your job.
1. Calculate the Number of Bricks that you will need
First calculate the area of wall needed. This can be done by multiplying the Length x Height for all sides.
If you are building one wall which is 4m in length and 2m in height.
Total surface area of that wall = 4m x 2m = 8m2
How many Bricks Needed = Area of Wall / Area of the Brick
Standard brick size is: 215 (length) x 102.5 (width) x 65mm (Height)
So, brick area would be: 0.215m (length) x 0.065m (Height) = 0.014m2 (easier to work in meters)
Number of Bricks for Required for Wall = Overall wall area / individual brick area
= 8 / 0.014 = 571.4 = 572 Bricks are needed
2. Calculate the Ratio of Cement and Sand from this Volume
At Warton Woodworks we estimate that 1Kg of mortar is needed to lay each standard size brick, and 2.3Kg of mortar to lay a concrete block such as thermalite.
Based on the above (step 1) we have 572 bricks that are required to build the wall.
So, total weight of mortar needed is: 572 x 1 = 572Kg.
Now, Lets Break that down in Ratios of Cement and Sand Required
Mortar = 4 parts sand : 1 part cement
Sand required is: (572 / 5) X 4 = 457.6Kg
Cement required is: (572 / 5) X 1 = 114.4Kg
How to Mix Mortar for Bricklaying via a Cement Mixer
Now you are ready to mix this sand and cement using your cement mixer, to a ratio of 5 to 1. Do not throw everything in at once, it is important to mix the water, sand and cement slowly, a bit at a time. Below explains how this is done:
- You will need to fill two of your builders buckets up with water.
- Add 60ml of mortar plasticiser to both buckets.
- Pour quarter of 1 bucket into the mixer followed by 1 bucket of building sand.
- Then add more water.
- Now add 1 bucket of sand. Followed by more water. Wear eye protection when mixing mortar.
- Make sure the sand is nice and wet before you add the cement, but not too much so it is spilling out of the front of the mixer.
- Add 1 bucket of cement and let It work its way into the sand.
- Add another 3 buckets of sand, whilst adding water in between and let it mix until you have a creamy, fluffy mix.
- Check to see if your mix is correct. A too sloppy mix will make a mess of your brick work as it runs down the brick faces. A too stiff mix makes it hard to level and plumb the wall in, and you end up pushing the bricks off when you are pointing the face work. You can over mix the mortar too, so don’t leave the mixer running unattended at any time.
- Once you are satisfied the mix is correct, use some water to wet inside the wheelbarrow.
- Pour about a buckets worth of mortar out of the mixer into the wheel barrow. It is advisable to work from the wheelbarrow to do the setting out course as it keeps wet for a longer period, as the setting out course is slower to install.
- You should now have your perfectly mixed mortar.
- Repeat from step 1 to create more mortar if necessary.
- We hope you have enjoyed this how to mix up mortar for bricklaying article.