How to Mix Mortar for Bricklaying
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.
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 Volume of the Brick Wall that will be Built
Total wall volume = Length x Height x Thickness (width)
For example, if a brick wall will measure 2m X 1m X 0.1m
Total volume = 0.2m3
2. Calculate the Ratio of Cement and Sand from this Volume
To calculate the weight of sand and cement needed for your mortar mix. We first need to know the total weight of the final product, being the mortar you will be creating. In general mortar weights about 2080kg per cubic meter, this is known as the density of mortar.
Total weight off mortar = Volume of wall needed X Density of mortar
For example, if the volume of mortar needed for the job equals 0.2m3.
Total weight off mortar = 0.2 X 2080
Total weight off mortar = 416kg
Mortar = 4 parts sand : 1 part cement
Sand required is (416 / 5) X 4 = 333KG
Cement required is (416 / 5) X 1 = 83KG
Mixing up 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.