How to Mix Brick Mortar (and How Much You’ll Get Out of a Batch)
Whether you’re laying bricks for a backyard wall or stacking up some heavy-duty Besser blocks, knowing how to properly mix mortar is one of the most important steps in bricklaying. Get it wrong, and things fall apart (literally). Get it right, and you’ll end up with strong, durable results that last decades.
In this guide, we’ll walk through how to mix mortar the right way, how many bricks or Besser blocks you can expect to lay per batch, and how much concrete mix you’ll need for core-filling those blocks.
Let’s get stuck in.
What Is Mortar Made From?
Mortar is a mixture of cement, sand, and water. A plasticiser is often added for better workability, especially when laying bricks or blocks all day in varying weather conditions.
The most common mix ratio for general-purpose bricklaying is:
1 part cement : 4 parts sand
Optional:
Plasticiser: A liquid additive that improves the workability of mortar without adding excess water. It makes the mix smoother and easier to spread, helps it stick to bricks better, and improves bonding strength. For best results, use 1 capful of plasticiser per standard wheelbarrow batch.
For most backyard or retaining walls, a 1:4 or 1:5 mix (cement to sand) will do the job.
Tools & Gear You’ll Need:
Cement
Brickie’s sand (aka fatty sand)
Mixing trough, wheelbarrow, or cement mixer
Shovel or hoe
Trowel
Water
Plasticiser
How to Mix Mortar (Step by Step)
Step 1: Measure the Ingredients
For a standard batch of mortar:
1 x 20kg bag of cement
16 full shovels of brickie’s sand (roughly equivalent to 4–5 buckets)
1 capful of plasticiser (added to water)
This combination gives a consistent, workable mix ideal for laying bricks or Besser blocks.Grab your cement and sand, and stick to a consistent ratio. For a standard batch:
1 x 20kg bag of cement
4 to 5 buckets of sand (roughly 80–100kg total)
Step 2: Dry Mix First
Shovel the sand and cement together in your wheelbarrow or mixing tray until it’s a uniform colour. This ensures the cement is evenly spread through the sand.
Step 3: Add Water Slowly
Make a crater in the middle and gradually add water. You want a firm but workable mix. Too dry and it won’t stick to your bricks. Too wet and it’ll slump and crack.
Ideal mortar has the consistency of peanut butter: it holds on the trowel without dripping but spreads easily.
If you’re using plasticiser, add 1 capful per batch to the water before mixing it into the dry ingredients.
Step 4: Keep It Turning
If you’re mixing large batches, use a cement mixer and keep it turning until everything looks consistent. Mortar should be used within 1–2 hours. Don’t re-wet old mortar — it weakens the bond.
How Many Bricks Can You Lay with One Batch?
A typical wheelbarrow batch using one 20kg bag of cement and the right sand ratio makes approximately 0.06 to 0.07m³ of mortar.
This amount will lay:
Around 80 standard bricks (230mm x 110mm x 76mm) with 10mm mortar joints
Around 60 Besser blocks (390mm x 190mm x 190mm)
These figures can vary depending on your joint thickness and your speed, but these are reliable averages for planning material quantities.
How Much Mortar Per 1000 Bricks or Blocks?
If you’re planning a full wall or project, here’s a guide:
1000 bricks: approx 0.24–0.27m³ of mortar
1000 Besser blocks: approx 0.88–0.9m³ of mortar
That’s roughly:
12–13 full wheelbarrow loads for 1000 bricks
15–17 barrow loads for 1000 blocks
Or:
1 bag of cement per 80 bricks
1 bag of cement per 60 Besser blocks
How to Core-Fill Besser Blocks with Concrete
Core-filling gives strength to block walls, especially retaining walls, garages, or structural work.
What You Need:
General purpose cement
Washed concrete sand
10mm or 20mm aggregate (blue metal)
Water
Standard Concrete Mix Ratio:
1 part cement : 2 parts sand : 3 parts aggregate
Add water until the mix is wet enough to pour but not sloppy
Volume Per Core:
1 core = approx 0.0083m³
So, for every 120 Besser blocks, if all cores are being filled:
120 blocks x 0.0083m³ = 1m³ of concrete
You’ll need approximately:
13–14 bags of cement (20kg)
Approx 0.4–0.45m³ of sand
Approx 0.6–0.65m³ of aggregate
Pro Tip:
If you’re only filling vertical cores (every second or third block), divide your total volume accordingly. Use a funnel or core-filling pump for cleaner, faster work.
You’ll need approximately:
5–6 bags of cement (20kg)
Approx 0.23–0.25m³ of sand
Approx 0.35–0.4m³ of aggregate
Pro Tip:
If you’re only filling vertical cores (every second or third block), divide your total volume accordingly. Use a funnel or core-filling pump for cleaner, faster work.
Tips for Better Mortar Work
Use brickie’s sand: It has the right clay content for mortar to stick and stay workable
Add 1 cap of plasticiser per batch for smoother, easier-to-use mortar
Don’t over-water: Weakens the bond and leads to cracking
Only mix what you can use in 1–2 hours
Keep your tools and board clean to avoid contamination
Brisbane Bricklayer Tips and Final Thoughts
Whether you’re a weekend DIYer or a seasoned Brisbane bricklayer, mixing mortar is part art, part science. Once you get the feel for it, you’ll start to know what good mud looks like just by eye. Knowing how far a batch will go saves time, money, and stress when ordering materials or planning your build.
To recap:
One bag of cement with proper sand ratio gives around 0.06–0.07m³ of mortar, enough for 80 bricks or 60 Besser blocks
1000 bricks = approx 0.25m³ of mortar
1000 blocks = approx 0.88–0.9m³ of mortar
Core-filling 100 blocks = approx 0.35–0.4m³ of concrete
Get your mix right, and your wall will stand strong for decades.
Need help working out your materials for a bigger job? Reach out — whether you’re a fellow Brisbane bricklayer or just getting started, we’re always happy to run the numbers and help with your next build.
