Sharp Sand vs Building Sand: Which Should You Use and Why?

Mix the wrong sand, and you’ll know about it when your new patio sinks or your mortar starts cracking.

This guide explains the real-world differences between sharp sand and building sand, when to use each, and what to avoid. Whether you’re mixing mortar or bedding slabs, understanding the basics will save you time, money and rework.

At a Glance: The Key Differences

Understanding Sharp Sand

Sharp sand, also known as grit or screeding sand, is a coarse aggregate made from crushed rock – usually quartz. The grains are rough and angular rather than rounded, which helps them lock together and create a strong bond when mixed with cement.

Because it’s less refined than softer sands, sharp sand is ideal wherever strength and stability matter more than a smooth finish.

Common uses

Sharp sand is used for heavy-duty applications such as:

• Bedding paving slabs and block paving
• Making concrete mixes
• Laying patios and driveways
• Screeding and external rendering
• Improving clay soils and drainage

For patio bases, one tonne of sharp sand covers roughly 12 m² at 50 mm depth – a quick rule of thumb for estimating quantities.

In gardens, mixing sharp sand through compacted or clay soil helps water drain and roots breathe more easily.

Understanding Building Sand

Building sand, often called soft sand or bricklayer’s sand, has a finer, smoother texture than sharp sand. It’s washed and screened to remove larger particles and impurities, giving it a soft, workable consistency.

The grains are smaller and more rounded, producing a smooth finish when used in mortar. It’s typically a warm beige or orange colour due to natural iron content.

Common uses

Building sand is ideal for:

• Bricklaying and blockwork
• Internal and external rendering
• Pointing and plastering
• Bedding pond liners or decorative features

If you’re repointing old brickwork, a lime-based mortar with soft building sand allows gentle flexibility and reduces cracking over time.

Its fine texture makes it easy to trowel, spread and shape without cracking as it dries – perfect for precision work.

Choosing the Right Sand for the Job

If you’re unsure which type you need, think about what the sand is doing in your mix. Sharp sand builds strength; building sand builds finish.

Use sharp sand when:

• You need rigidity and load-bearing strength (concrete, paving, patios)
• The sand forms a base or foundation layer
• You’re improving drainage in soil

Use building sand when:

• You’re laying bricks or blocks
• You need a smooth mortar finish for pointing or rendering
• You’re working on interior or detailed finishes

A quick test: rub a handful between your fingers. If it feels coarse and scratches, it’s sharp sand. If it’s silky and smooth, it’s building sand.

Mixing Tips and Common Mistakes

Getting the right consistency is just as important as choosing the right sand.

• Measure by volume rather than by eye. A typical mortar mix is 4 or 5 parts building sand to 1 part cement.
• For concrete, combine sharp sand with gravel or ballast to improve strength.
• Don’t use sharp sand for mortar unless you want a rough, gritty finish – it won’t spread smoothly and may weaken the bond.
• Avoid using building sand in concrete or as a paving base; its fine texture can cause shrinkage and cracking once dry.

When mixing by hand, create a shallow crater in your sand pile before adding cement and water – it keeps the mix even and prevents dry pockets.

Other Common Sand Types

While sharp and building sands are the most common, a few specialist varieties are also worth knowing:

• Plasterer’s sand: Very fine and consistent, ideal for finishing coats of plaster or render.
• Ballast: A blend of sharp sand and gravel used for strong concrete.
• Play sand: Specially cleaned and rounded for children’s sandpits – not suitable for construction.

Frequently Asked Questions

Can I use sharp sand instead of building sand for bricklaying?
No. Sharp sand’s coarse grains create a weak, gritty mortar. Use building sand or a dedicated bricklaying mix for strength and smoothness.

Why does some building sand look orange?
The colour comes from natural iron minerals in the source material. It won’t affect performance, but it can slightly change the shade of your finished mortar.

Can I mix sharp and building sand together?
Yes, in some cases. A 50/50 blend creates a coarser mortar suitable for garden walls or paving edges, though not ideal for fine brickwork.

Is sharp sand the same as ballast?
No. Ballast is a mix of sharp sand and small stones used to make concrete for heavy-duty work.

Which is best for soil improvement?
Sharp sand. Its coarse, angular grains open up compacted ground and improve drainage.

Final Takeaway

Choosing the right sand comes down to texture and purpose.
If you need a smooth, workable mortar, go for building sand.
If you’re after strength and durability, go for sharp sand.

Think of it like this: sharp sand carries the weight, building sand holds the detail.