Sharp Sand vs Building Sand: Which Do You Need?

Ordering sand sounds simple until you find three different kinds on the list. Choose the wrong one and you can end up with weak mortar, a crumbly screed or paving that will not stay level. Here is how sharp sand, building sand and plastering sand differ, and what each is best for.

Sharp sand (also called grit sand)

Sharp sand has larger, more angular grains, which gives it a coarse, gritty feel. Because the grains interlock and the gaps between them are larger, it makes strong, free-draining mixes and compacts well.

Best for:

• Bedding patio slabs and block paving
• Floor screeds
• Concrete mixes, combined with gravel or stone
• Sand and cement mixes where strength matters more than workability

We stock it as a sharp / grit sand bulk bag and a sharp / grit sand trade pack.

Building sand (also called soft sand)

Building sand has finer, rounder grains and a smooth, almost soapy feel when mixed. That makes mortar easy to work, spread and shape, and it gives a neat, workable joint.

Best for:

• Mortar for bricklaying and blockwork
• Pointing
• Internal rendering and general building work

It is available as a building sand bulk bag and a building sand trade pack.

Plastering sand

Plastering sand is a finer grade again, which gives smooth finishes in base coats and smooth-finish mortars. We sell it as a plastering sand bulk bag and a trade pack. It suits internal plaster base coats and sand and cement render. For plastering projects, check the product you are using, since many plasters are supplied ready mixed and need no sand at all.

Side-by-side

	Sharp sand	Building sand	Plastering sand
Grain	Coarse, angular	Finer, softer	Fine
Feel	Gritty	Smooth	Very smooth
Main use	Paving bed, screed, concrete	Bricklaying and pointing mortar	Render and plaster base coats

Common mix-ups

• Using building sand under paving. It is a popular shortcut, but fine sand holds water, compacts less well and can leave slabs settling unevenly. Sharp sand is the usual choice for the bedding layer.
• Using sharp sand for bricklaying. The coarse grains make mortar harsh and hard to spread, and joints look rough. Building sand is the standard.
• Treating them as interchangeable in a screed. Screeds are normally made with sharp sand, for strength.

Mortar ratios are covered in our guide to sand and cement mix ratios.

Quick checklist

• Laying slabs or block paving: sharp sand.
• Laying bricks or blocks, or repointing: building sand.
• Rendering or plaster base coats: plastering sand.
• Making a screed or concrete: sharp sand, or all-in ballast for concrete.
• Not sure? Call us on 03330 908479 with the job and we will point you to the right one.

How much sand do I need?

Work out the area and depth in the same way as for a sub-base, then convert to weight. Loose sand weighs very roughly 1.6 tonnes per m³, though it varies with how wet it is. As an example, a 40mm sharp sand bedding layer under a 12m² patio is 0.48m³; with a 10% allowance that is 0.53m³, or about 0.85 tonnes, which means two 800kg bulk bags. Our guide to paving bedding quantities goes through it in more detail.

Frequently asked questions

Can I use sharp sand for mortar?

Some people do for strong mixes, but it is harsher and harder to work than building sand. For bricklaying and pointing, building sand is the usual choice.

Is builders sand the same as building sand?

Yes. "Builders sand" and "soft sand" are common names for building sand.

Which sand do I use under slabs?

Sharp sand is normally used for a bedding layer, or as part of a sand and cement bedding mortar. Follow your paving manufacturer's laying instructions.

Does sand come wet or dry?

It is typically supplied damp, and the packed weight changes with moisture, which is why our bulk bag weights are approximate (up to 850kg).

Do you sell sand in small bags?

Yes, our sharp, building and plastering sands also come in 20 to 25kg trade packs, which are handy for small jobs.

Ordering and delivery

You can browse the full range in our cement and aggregates collection. Bulk bags are sold at approximately 800kg each (the packed weight can be up to 850kg depending on moisture), and most sands and gravels are also available in 20 to 25kg trade packs for small jobs. Prices on our website are shown excluding VAT, and VAT is added at checkout.

We deliver to addresses in mainland England only; we do not currently deliver to Wales, Scotland, Northern Ireland or the islands. Timber, aggregates and cement have a minimum order of £250 ex VAT, and delivery is £25 ex VAT on orders under £500 ex VAT and free over £500 ex VAT. Bulk bags are delivered by Moffett lorry (truck-mounted forklift) and offloaded at your site, so someone must be there to receive them and you will need a firm, level area with suitable access. We do not offer next-day delivery. Our shipping policy has the full details, or call us on 03330 908479 or email sales@insulationwarehousedirect.co.uk if you would like a hand working out your order.

The quantities in this guide are estimates. Ground levels, how well the material is compacted and how wet it is all change what you need, and densities vary between quarries, so check the amount with your installer or the manufacturer's guidance before you order. Prices and pack sizes are correct at the time of writing.

Working out quantities? See our MOT Type 1 sub-base guide: how much do I need? or go straight to our aggregates calculator.