Sharp sand has coarse, angular grains up to around 4mm and is used for concrete, floor screeds and bedding block paving. Building sand has fine, smooth grains under 2mm and is used for mortar in bricklaying and pointing. Sharp sand is stronger. Building sand is easier to work with a trowel.
Two bags of sand sitting side by side in a builders merchant, both yellow, both about the same price, and picking the wrong one will cost you the job.
This is the question we get most often on the aggregates line, and it usually comes with a second question attached, which is whether the name on the ticket means what the customer thinks it means. Sand has a lot of names in this trade and most of them overlap. We’ll clear that up first, then get into what you use where.
Sharp sand, otherwise referred to as grit sand, is a coarse sand with angular, gritty grains. Run it through your fingers and you can feel the individual particles. Grain size goes up to around 4mm, with a spread of sizes below that.
Those angular edges are the whole point. When sharp sand is mixed with cement, the grains interlock and grip rather than sliding past one another, which is what gives concrete and screed their strength. It is normally washed during production to take out clay and silt, so it is cleaner than building sand and holds less water.
The colour ranges from pale grey to a strong orange depending on where it was dug. Colour tells you nothing useful about quality, so ignore it.
You will see the same material sold under several names, and for practical purposes they mean the same thing:
Grit sand is the most common alternative name. If you are asking whether grit sand is the same as sharp sand, the answer is yes in nearly every case. Garden centres sometimes sell a horticultural grit sand for lawn top dressing, which is washed sharp sand with a tighter grading, so it is the same material screened more carefully.
Concreting sand is sharp sand sold specifically for concrete mixes.
Coarse sand and washed sharp sand both describe the same product.
Building sand is a fine, soft sand with smooth, rounded grains, generally under 2mm. It feels silky rather than gritty.
Those rounded grains slide over each other easily, and that is what makes mortar workable. A good bricklaying mortar needs to sit on the trowel, spread cleanly and stay put on the brick without slumping. Building sand does that. Sharp sand does not.
Building sand contains more clay and silt than sharp sand, which adds to the plasticity of the mix. That is a benefit in mortar and a problem almost everywhere else.
Soft sand is the most common alternative, and describes the texture well.
Builders sand and building sand are the same thing. If you are wondering whether builders sand and sharp sand are the same, they are not. Builders sand is the fine one.
Bricklaying sand and red sand or yellow sand all normally refer to building sand.
Plastering sand is a related but slightly different product. It is a building sand screened finer and washed more thoroughly, so it gives a smoother finish on a plaster or render coat. Plenty of merchants sell one product for both jobs.
So, to answer the question directly: no, building sand is not the same as sharp sand. They are different materials with different jobs, and swapping one for the other causes real problems.
| Sharp sand | Building sand | |
| Grain size and texture | Up to 4mm, angular and gritty | Under 2mm, smooth and soft |
| Also known as | Grit sand, concreting sand, coarse sand, washed sharp sand | Soft sand, builders sand, bricklaying sand, yellow or red sand |
| Clay and silt content | Low, usually washed | Higher |
| Best for | Concrete, floor screeds, block paving bedding, slab bedding | Bricklaying mortar, blockwork, pointing, rendering |
| Not suitable for | Bricklaying mortar, pointing | Concrete, block paving bedding, screeds |
| Typical mix ratio | 1 part cement to 3 or 4 parts sand for screed | 1 part cement to 4 or 5 parts sand for mortar |
| Workability with a trowel | Harsh, drags | Smooth, holds its shape |
| Strength when set | Higher | Lower |
Use sharp sand when the mix needs strength, or when the sand is going down loose as a bedding layer.
Concrete is the main one. Sharp sand goes in alongside 20mm aggregate and cement, or you can buy it pre-blended as ballast. Our guide to the best aggregate for concrete covers the mixes in more detail.
Floor screeds use sharp sand at roughly 1 part cement to 4 parts sand. Building sand in a screed will craze and dust up on the surface.
Block paving bedding uses sharp sand laid loose and screeded flat, usually 30mm to 50mm deep over the sub-base.
Slab and flag bedding uses sharp sand in a mortar bed, typically 4 to 1 with cement.
Base coats for render sometimes use sharp sand, or a blend of sharp and soft, depending on the substrate and who you ask.
Use building sand whenever you want a mix that behaves well on a trowel.
Bricklaying mortar is the obvious one, normally 4 or 5 parts building sand to 1 part cement, often with a plasticiser or lime.
Blockwork mortar is the same mix.
Pointing and repointing want building sand, and it wants to be a fine, consistent one so the joints look even.
Rendering uses building sand or plastering sand, usually in a weaker mix than bricklaying mortar so it can move slightly without cracking.
Haunching around edging kerbs and setts is normally done with a stiff building sand mortar, though some groundworkers use sharp for extra strength on driveway edges that take wheel loads.
Technically yes, and it will set. In practice you will not enjoy it and the finish will suffer.
Sharp sand mortar is harsh and stiff. It drags on the trowel, it does not spread cleanly, and it will not stay on the brick the way a soft sand mix does. Bricklayers describe it as fighting you. Your joints will look rough and the pointing will be difficult to finish neatly.
There is also a technical reason to avoid it. A mortar that is significantly stronger than the bricks around it is a problem, because it stops the wall flexing and pushes any cracking into the brick face instead of the joint. Mortar is meant to be the weaker element. Sharp sand mortar can end up too strong, particularly on older or softer brickwork.
Where sharp sand does belong in a mortar is bedding slabs and haunching kerbs, where you want strength and you are not trying to finish a visible joint.
If you have sharp sand on site and no building sand, a compromise is to mix the two, roughly half and half, which improves workability while keeping some strength. It is not ideal, but it will get you through a small job.
This is the swap that causes the most damage, and the answer is no for anything structural.
Building sand in concrete gives you weak concrete. The rounded grains do not interlock, the higher clay content interferes with the cement bond, and you can lose a significant amount of compressive strength. For a shed base that might not matter much. For foundations or a driveway slab, it matters a great deal.
Building sand under block paving is worse, and we see the results of it regularly. Soft sand holds water, does not drain, and does not stay put. Blocks sink where the wheels run, the surface goes wavy within a year or two, and the only fix is lifting the whole lot and starting again. It’s best to just use sharp sand from the start. Building sand in a screed will dust and craze on the surface.
The one place the swap is harmless is a very small non-structural job where nothing is carrying load and nothing is going to get wet.
Sharp sand, and specifically a washed sharp sand or grit sand.
The build-up on a domestic driveway usually goes like this. Compacted MOT Type 1 sub-base at 150mm, then 30mm to 50mm of sharp sand screeded level as a laying course, then the blocks, then kiln dried sand brushed into the joints.
Three separate materials and it is worth keeping them straight. The sub-base is stone, not sand. The laying course is sharp sand, laid loose and screeded, never mixed with cement. The jointing sand is kiln dried sand, which is a very fine dry sand that runs down into the narrow gaps between blocks. Building sand appears nowhere in that build-up.
If you want the full detail on the layer underneath, we have written up a guide to the best aggregate for driveways.
Sharp sand, mixed with cement into a mortar bed.
The standard for patio slabs is a full mortar bed at roughly 4 parts sharp sand to 1 part cement, laid at 30mm to 50mm and worked so the slab beds down onto solid support across its whole underside.
Avoid the five blob method, where five dabs of mortar go under each corner and the middle. It is quick and it is still common, but it leaves voids under the slab, and slabs bedded that way crack when somebody stands on an unsupported corner or water gets underneath and freezes.
Some landscapers add a splash of SBR bonding agent to the mix, or prime the back of the slab with a cement slurry. Worth doing on porcelain and dense natural stone, which do not bond well to mortar on their own.
Sand weighs roughly 1.6 tonnes per cubic metre, so the sums are straightforward.
For a bedding layer, multiply length by width by depth in metres, then multiply by 1.6.
A driveway 8 metres by 3 metres with a 50mm sharp sand laying course:
8 × 3 × 0.05 = 1.2 cubic metres 1.2 × 1.6 = 1.92 tonnes
Order 2 tonnes.
As a rough coverage figure, one tonne of sharp sand covers about 12 square metres at 50mm deep, or about 6 square metres at 100mm.
For mortar, the usual rule of thumb is that a tonne of building sand with somewhere around 8 to 10 bags of cement will lay in the region of 1,000 bricks. That varies with joint thickness and how heavy handed the bricklayer is, so treat it as a starting point rather than a precise figure.
Bulk bags hold between 800kg and a tonne. On anything above about three tonnes it is usually cheaper per tonne to have it tipped loose, if you have somewhere to put it.
We supply sharp sand, building sand and plastering sand across the North West, usually same or next day. We have been doing it from our yard on New Zealand Road in Stockport since 2009.
We also carry the rest of what you need for the same job, so a driveway build can come on one delivery rather than three. Have a look at our full aggregates range, or ring us on 0161 470 0220 and tell us what you are building.
If you are not sure which sand the job needs, ask before you order. It takes a minute on the phone and it is a lot cheaper than lifting a driveway.
Is grit sand the same as sharp sand?
Yes, in normal building use they are the same material. Grit sand is just another name for washed sharp sand. Horticultural grit sold for lawns is the same thing with a tighter grading.
Is building sand the same as sharp sand?
No. Building sand is fine and soft and is used for mortar. Sharp sand is coarse and gritty and is used for concrete, screeds and bedding. They are not interchangeable.
What happens if I use the wrong sand?
Building sand in concrete gives weak concrete. Building sand under block paving causes sinking and rutting within a couple of years. Sharp sand in mortar is hard to work and can end up stronger than the bricks, which pushes cracking into the brick face.
Can I mix sharp sand and building sand together?
You can, and some renderers do it deliberately to balance strength against workability. For a small mortar job with only sharp sand on site, a half and half blend is a reasonable compromise. For concrete or a block paving laying course, use sharp sand on its own.
Which sand goes between block paving joints?
Kiln dried sand, which is different from both. It is a very fine, very dry sand that brushes down into narrow joints. Sharp sand is too coarse and building sand is too damp.
Do I need to wet the sand before mixing?
Sand usually arrives with some moisture in it already, and how much affects how much water your mix needs. Add water gradually rather than to a fixed measure, and judge the mix by how it behaves rather than by the bucket count.