Let’s put an end to the confusion that often surrounds the terms mortar, cement and concrete. Here you’ll find answers to the most frequently asked questions to gain understanding about these essential construction materials
What's Plasticizer?
Plasticizer is a liquid that’s added to make the mortar mix easier to work with and stop the mortar from drying quickly. Adding plasticizer to the water produces bubbles which aerates the mortar mix giving it a ‘fluffy’ texture.
Examples of products you can use are ‘brickies mate’ or ‘Lanko 5L 311 Bricklayers Plasticiser’.
Trade Tip
If you don’t have plasticizer on hand, you can use a splash of detergent as an alternative. Use as described on this link – in step 4 of Mixing Mortar.
What is the mortar mix for stone walls?
The recipe is 3 sand : 1 cement : plasticiser and add oxide to suit the color of the stone. Oxide is available in a range of color to choose from – red, black, brown, ochre etc.
- Don't guess! When adding oxide to the mortar mix always add exactly the same quantity to each mix. A slight variation in quantity can lead to significant variations once the mix dries. Consistency is key for optimal results.
Determine the color you want first and then stick to that formula.
For example, you could use 3 sand : 1 cement : 1/2 cup of oxide mixed into the water with the plasticizer. Use a small container, (eg. a measuring cup). The next mix must be measured using exactly the same recipe.
Important
This mix is not structural. It’s used with the rock as a cladding on the outside of an already constructed concrete masonry wall which is built to an engineer’s specification.
What's the mortar mix for sandstone walls?
A sandstone mortar mix is used for grouting sandstone. and the key thing here is that the color of the sandstone determines the color of the sand and cement you need to use.
Recently I laid ‘crazy pave’ sandstone on a path. I used tile glue to lay the sandstone onto the concrete pathway and then used a sandstone mortar mix to grout.
The recipe that suited the colors in the sandstone was: 3 shovels of white beach sand to 1 shovel of white cement + plasticizer.
You may have to do some research on the sand you choose, as there are so many different colored sands. To find the color that best suits the sandstone that you’re laying, I suggest mixing a small quantity as a test (you can use a tablespoon to mix the ratio) and leave it to dry in the sun. When it’s dry, check the suitability of the color.
What is a white mortar mix?
When making a white mortar you have to choose a white sand. Usually the white sand doesn’t have clay or loam in it so it’s ‘dead’ which means you need to add lime.
The recipe ratio is 3 shovels of bleached white sand: 1 shovel white cement : 1 shovel of lime
Important
Exercise caution when using lime as it burns the skin and eyes. Use appropriate protective clothing, glasses, gloves and equipment to protect yourself.
What is ready mix mortar?
It’s a premixed bag with the correct ratio of brickies loam and cement. Handy as a quick fix for small jobs only.
The advantage is every 10 kg bag always makes a consistent mix. It’s available online, from hardwares and landscape supplies.
Do I need to add lime to a mortar mix?
No. The addition of Lime makes the mortar more workable, but it’s rarely used because it tends to burn your skin and eyes. Plasticiser is used instead.
There are 2 exceptions.
- If you’re building a bbq, fireplace or pizza oven. In these instances it’s a good idea to use lime because lime helps with ‘movement’ caused by extreme temperature changes.
- A white mortar mix as white sand doesn’t have clay or loam in it so it’s a ‘dead’ mix and needs the addition of lime.
Caution applies when using lime. Protect your skin and eyes as lime burns.
What's the difference between mortar and concrete?
- Mortar is used to lay bricks.
- Concrete is structural and used in construction. For example footings, slabs and filling besser blocks. You wouldn’t use mortar to make a slab (you’d use concrete).
- Concrete is made up of sand, gravel and cement.
- Mortar is made of brickies loam, lime and cement.
What is brickies loam?
Brickies loam is a 50/50 mix of sand and loam and is the name of the product to ask for at your local landscape supplier. It’s used to mix the mortar for laying bricks and blocks.
Note: For small jobs you can buy a bag of pre-mix mortar. Each bag contains the correct ratio of brickies loam and builders cement.
Although this is an easy option for small jobs, I don’t recommend buying pre-mix for larger jobs as it’s not cost effective.
What is cement?
Builders cement is the product that’s added to sand and gravel to made concrete or added to brickies loam to make mortar. Cement is supplied in a bag.
This is a cement mortar receipe:
Mix ratio: 4 shovels brickies loam : 1 shovel builders cement + water + plasticiser