To those new to the world of DIY and construction, you may think that sand is just sand but this is certainly not the case, there are quite a few different types of sand, with each specific to certain jobs.
Using the right type of sand for the particular job you are doing is hugely important as using the wrong grade can be disastrous.
For example, using a very fine sand instead of building sand when making mortar can mean that it doesn’t bond correctly to bricks or blocks and could lead to the structure your building collapsing!
To add to the confusion of not only having various different types of sand, each different type of sand can have up to 10 different names depending on the area of the country you’re in and what trade you’re involved in.
This is not only confusing to DIY newbies but can also be equally as confusing to the professionals!
With this in mind, this project will look at the main different types of sand, the grade of each type of sand and what each different type of sand should be used for.
What is Sand?
Before we get into exactly what types of sand there are and how each should be used, it would be a good idea to find out what sand actually is and where it comes from.
Sand is essentially made from rocks that have been broken up and eroded over time and ground down to form much smaller particles.
One of the primary ingredients of sand is silica. This is a naturally occurring material that is found in nearly a quarter of the Earth’s crust.
Apart from sand, silica is found in a great many other materials, both naturally occurring and man-made materials. Some of these include quartz (one of its most common occurrences), clay, glass, silica gels and also in some food stuffs and medicines.
As mentioned, silica or fine rock particles forms the bulk of a body of sand and quartz tends to be the most common material that effectively forms the silica. The quartz itself (otherwise known as silicon dioxide) is formed when oxygen combines with silicon.
One of the other key constituents of sand is Feldspar. Feldspar is an extremely common group of minerals that makes up nearly three quarters of the Earth’s surface.
Over time, and through the action of the wind, waves and erosion, quartz and feldspar combine (along with other materials such as bone, shell, coral, glass and as many should now be aware, plastic) and forms sand on beaches, river beds and around lakes and other shorelines.
Typically, sand and other similar materials such as gravel/grit or silt (commonly found on river beds and river banks) is classified by the size of its grains. Sand itself sits between gravel and silt with its grains being smaller than those that make up gravel but larger than those that make up silt.
As a general rule, sand is classified as such if its particles range from 2mm at largest down to 0.06mm at their smallest.
As we briefly mentioned above, sand is arguably one of the most used materials in the building trade. It’s used to make concrete and mortar, bricks and blocks, glass, casting moulds and many other things.
Due to this, the demand for sand is massive, not only in the UK but across the entire globe and as with any other naturally occurring resource, there is only a finite supply and stocks will inevitably start to run out at some point in the not too distant future!
With this in mind, sand should be treated as a precious resource and wastage kept to a minimum, not only to preserve the sand itself, but to also minimize the environmental impact that goes with having to supply billions of tonnes of sand globally.
One final point to note with the sand used in construction is that it should be as clean and free from impurities (soil, clay etc) as possible and also, as uniform in terms of grain size as possible depending on the type you are using.
Why Does Sand Come in Different Colours?
If you have done any concreting in the past or had to mix any mortar to lay bricks or blocks you will almost certainly have had to purchase some sand from a builders merchant or DIY shed.
In the majority of cases, the sand on offer will be a yellowy orangey colour just as you may imagine it to be.
On some occasions the available sand may also be a reddish colour.
You may have also experienced the situation where you purchase one bag of standard yellow builders sand only to find you run out before the job is finished.
After another trip to the builders merchant you then discover the only builders sand they have is a red colour which results in your mortar being two different colours, leaving you in the quandary of whether to just use it as it is or try and colour match it using a mortar tone or other colouring method.
The reason for this is down to where the sand has come from. Sand produced in one area of the country may have a slightly higher iron-oxide content, giving it a reddy orange appearance, where as sand from another area of the country may feature more coral or shell content giving it a whiter appearance.
Now that you know why some sand is a different colour to other sand you may also be thinking, why would it suddenly change colour even though I’m getting it form the same place?
The answer to this question has to do with the previously mentioned fact that sand, as a commodity, is in short supply and as large DIY chains tend to buy in massive bulk quantities, their normal supplier may not be able to supply them in these quantities from their normal go-to source due to low stocks.
When this happens, sand need to be sourced from another supplier or location where it may be of a slightly different colour, hence the difference.
As we have mentioned, if it’s of prime importance that your mortar does match the colour of the existing mortar then you can add certain dyes and tints that will help you colour-match it.
For more information on how to match mortar colours, see our project here.
You may also want to check out our product review of a very good tint and colour-match dye made by Bebbington Brick here.
What are the Different Types of Sand and What Should They be Used for?
Now that you know a little more about where sand comes from and why its colour can vary so much it’s time to look at the different types of sand and how they should be used.
Sharp Sand (aka Coarse Sand or Pit Sand)
This type of sand is a fairly coarse type of sand due to the fact that the particles that make it up are fairly large. Typically the grain particles are also quite sharp and angular in shape.
It’s primarily used in making concrete as due to the shape of the grains, it binds extremely well to form a tough and solid surface, but due to the size and shape of particles, not that smooth.
As it is mainly mined from inland areas away from the coast it does not contain salts that would otherwise allow it to absorb atmospheric moisture and this makes it idea for use in the building trade where moisture and damp issues need to be avoided.
The name “pit” refers to how its sourced; It’s essentially dug out of a large pit from ground, roughly 1-2 metres below ground level.
More often than not, sharp sand or pit sand has a orangy red colouring as it is often found in areas with concentrations of iron-oxide.
One important note is that for any concreting or mortar applications, there should be absolutley no more than 4% silt present in the sand.
To summarize, sharp sand should be used for:
- Masonry Work
Builders Sand – (aka River Sand, Screeding Sand, Plasterer’s Sand, Mason’s Sand or Bricklayer’s Sand)
Unlike the sharp sand above, builders sand is much finer due to the fact that the grains are much smaller.
In terms of the grains, unlike the coarse sharp and angular grains that make up sharp sand, the grains found in builders sand are much more rounded and smoothed off.
As the grains are smaller and smoother, this results in a much smoother overall finish hence the reason builders sand is used in screeding and plastering applications.
As the name suggests (e.g. river sand) this sand-type is normally collected from the beds and banks of rivers or from around more inland water sources as, again, the presence of salts and other organic matter needs to be kept to a minimum to ensure that atmospheric moisture is not absorbed that could then cause damp issues.
In terms of colouring, builders sand normally tends to be a light grey colour and can in some instances appear almost white.
In summary, builders sand should be used for:
- General mortar/masonry work
- Brick and block laying
Jointing Sand – (aka Sea Sand, Silver Sand, Washed Sand or Beach Sand)
Keeping with the theme of the name describing where a given type of sand is sourced from, jointing sand or beach sand is collected mostly from beaches and areas around coastlines.
Beach sand is also known as washed sand which relates to the way in which it’s processed in that it is washed through to remove any unwanted dust, clay, silt, sediment etc. after which it is then left to thoroughly drain.
In terms of the grains that make up beach/jointing sand they do tend to be very fine and through the action of the tides swooshing everything around do also tend to be very smooth and rounded.
Colour-wise, beach sand is normally a yellowy, brownish colour.
Due to the fact that beach sand is collected from coastal regions, it does contain the afore mentioned salts that absorb atmospheric moisture and cause damp issues. Due to this it is not used widely in construction.
One other issue is that it also contains chloride and if you have ever witnessed an old piece of metal that’s been exposed to sea air for a period of time, you may have noticed that it’s probably heavily corroded (rusty).
With the above in mind and the fact that steel is widely used in the building industry, I’m sure you can see why this type of sand needs to be kept well away from any structural steel as it will cause it to corrode in a relatively short space of time.
Despite the above, beach sand does have some uses:
- Jointing paving and patio slabs
- Children’s sand pits (needs to be double washed to remove all contaminants)
- Recreational areas
- Golf bunkers
Artificial Sand – Crushed Stone Sand, M Sand
If you have already read through the above type of sand you should now have guessed that artificial sand (or M sand – manufactured sand) is named as such as it’s artificially created and not naturally sourced.
On a comparative level, artificial sand is a very close match to building sand mostly because building sand tends to be more widely used than any of the other types.
In terms of how artificial sand is made, generally, it is produced through crushing up basalt rock or granite rock and due to this is normally greyish in colour.
Although M sand or artificial sand is not that common at present it is gaining some ground due to the fact that natural builders sand is in short supply.
As it is aimed as a direct replacement for river sand, its grains are of a similar size and shape.
With the above in mind, it can be used in the following applications:
- General mortar/masonry work
- Brick and block laying
Other Types of Sand
Aside from the main or common types of sand above, there are other less common type available that are used mostly in specialist applications:
- Desert Sand: Sourced from desert areas and not suitable for construction uses due to grains being too fine and overly smoothed at present, although some are developing concrete substitutes using desert sand
- Biogenic/ Bio-organic Sand: Sand who’s makeup is largely from coral, shells and the skeletons of marine life
- Olivine Sand: Not suitable for use in construction applications due to the fact that it’s unstable, but is used for creating casts and moulds for steel
- Volcanic Sand: As the name may suggest, volcanic sand is found is areas of high volcanic activity
How is Sand Tested?
Aside from the size and shape of grain and where the sand originated from another very important fact that should be considered is how clean the sand actually is. By this we mean establishing its silt content.
We briefly mentioned above that the silt content of pretty much any sand used in construction should not be greater than 4%.
This is due to the fact that if there is a greater silt content then this can seriously effect the structural integrity of the concrete it’s used in.
For this reason, all sand used should be clean and free from clay, salts and any other impurities.
There is a method of testing the silt content of sand called (funnily enough) the “silt test”.
To perform a silt test you first need a solution of salt water mixed at 5ml of salt to 500ml of clean water.
Next, pour 50ml of the solution into a measuring jug and then add your sand sample so that it reaches the 50ml mark on your measuring jug.
Top up the jug to the 150ml mark with some more of the salt water solution you previously mixed and then cover the top of the jug and give it a good shake up to mix it all up.
Next, it’s a waiting game! The jug should be left for at least 3 hours for everything to settle. Once settled, all you need to do then is measure the layer of silt that has settled on top of the sand.
This should not be any more than 4% or 2ml in total.
Now that you know all about the different types of sand and what type should be used for a given DIY or construction job, all you need to do now is get on with your chosen project.