Do I need sharp sand or building sand for laying slabs?

If you’re planning to lay a patio, you might be wondering if you need to use sharp sand or building sand for laying slabs. Keep reading to find out.

What’s the difference between sharp sand and building sand?

Sharp sand is grittier and denser than building sand. It has larger grains and will last longer than building sand.

Building sand has much finer grains than soft sand and is often used for creating mortar for bricklaying.

Sharp sand is the most cost-effective choice while building sand creates a smoother finish.

What is the best mortar mix for laying slabs?

When laying slabs, the best method is to combine both sharp sand and building sand in your cement mix.

The general guide for sand to cement ratios for laying patio slabs is:

4 parts sharp sand, 1 part building sand, 1 part cement.

This will give you a smoother mortar than using just sharp sand but will also be more robust and durable than using just building sand.

How to lay patio slabs with a sharp sand and building sand mix

To successfully lay patio slabs use the following method:

1. Mix the mortar using the ratio above: 4 sharp, 1 building, 1 cement
2. Don’t use to much water while laying the slabs
3. Regularly wet the slabs over the next few days
4. Point the slabs with a strong cement mix – ratio 2 building, 1 sharp, 1 cement
5. Wet the slabs once a day for the next week

After a week, your patio will be ready to walk on.

Want to know more about laying patios? Check out our guide on how to lay a patio. 

Important considerations when laying patio slabs

Laying patio slabs is a skilled and very physical task. Some important things to consider when laying slabs include:

• Ensure that the top of your slabs are at least 150mm below the property’s damp course
• Lay the slabs with a slight gradient that runs away from the house
• Consider using a bonding agent in the sand/cement mix
• Check that your mortar is suitable for the type of slabs

As you can see, laying patio slabs is not a simple task.

If you’re unsure about laying patio slabs yourself, it’s always best to hire a professional. To find Checkatrade approved patio specialists in your area, simply enter your postcode into the box below.