Kiln Dried Sand: Everything You Need To Know

What is Kiln Dried Sand?

Kiln dried sand is fine, washed, dry aggregate sand that is brushed into paving joints to improve stability and help prevent slabs from moving. It is ready to use as an infill and contains almost no moisture, which helps to improve drainage and suppress weed growth.

It is also known as silver sand, kiln dried silica sand, paving sand, jointing sand, and block filling sand.

What is Kiln Dried Sand Used For?

Kiln dried sand is primarily used as an infill on patios and block paving to prevent slabs moving laterally, improve drainage, and suppress weeds. It is also used as a topdressing on artificial grass to reduce creases, static, and surface temperature.

It is the perfect sand for paving as it is an extremely finely graded aggregate and therefore fills every gap between the paving blocks. The grains, which are no larger than 0.5mm, work to create a tight infill and leaves no room for the slabs to move.

How Much Kiln Dried Sand For Block Paving?

You will need one 25kg bag per 25m2 of paving that requires resanding. If the block paving is new and it is being filled for the first time, one 25kg bag will cover 7.5m2. This calculation assumes you are using a 50mm block.

The exact amount will vary depending on the type of blocks you have used and the amount of sand dislodged when using a power washer to clean the paving.

This table shows how much kiln dried sand is needed to re-sand 5m2, 10m2, 25m2, 50m2, and 100m2, depending on the depth of paving.

Measurement of block paving in m2The amount of sand required to re-sand 50mm block pavingThe amount of sand required to re-sand 60mm block pavingThe amount of sand required to re-sand 80mm block paving

Note: these are estimates and should only be used as guidance.

Only use sand when your paving is completely dry. The slightest bit of moisture will reduce the ability of the sand to create a compact joint. It is recommended that you resand your block paving every 3-5 years.

Why Do You Put Kiln Dried Sand on Artificial Grass?

It is recommended that you put kiln dried sand on artificial grass to:
– Improve drainage
– Speed up dry time
– Prevent moss and weeds
– Weigh the grass down
– Straighten blades
– Prevent wrinkles 
– Reduce static
– Increase stability
– Reduce surface temperature

It also improves fire protection, which is important if you are going to barbeque food nearby.

While you do not absolutely need to use kiln dried sand on artificial grass, it is recommended. The additional cost of the top dressing will be recouped over time as it will perform better and benefit from an extended lifespan.

How Much Kiln Dried Sand Do You Need For Artificial Grass?

You need approximately 6kg of kiln dried sand per square metre of artificial grass. This means one 25kg bag will cover just more than a 4m2 area. You can improve coverage by spreading the sand thinner, however, this will reduce the effectiveness.

The table below shows how much kiln dried sand is required for a range of areas:

Size of artificial grass in m2How much sand will be needed to cover the surface in kgHow many 25kg bags of sand are required
1m26kg1 bag
5m230kg2 bags
10m260kg3 bags
25m2150kg6 bags
50m2300kg12 bags
100m2600kg24 bags

Note: these are estimates of coverage and will vary from project to project.

How Much Does Kiln Dried Sand Cost?

Kiln dried sand costs £6.34 per 25kg bag, which works out at £0.25 per kg. These costs are based on retail prices from builders merchants and include VAT. Customers can get a more competitive price if they sign up for a trade account or buy in bulk.

Can You Use Kiln Dried Sand For Sandblasting?

No. It is illegal and unsafe to use sand for sandblasting. This is because prolonged exposure to silica, which is a mineral found in sand, can cause lung disease. This goes for both wet and dry sandblasting.

Does Kiln Dried Sand Stop Weeds?

Kiln dried sand will help to stop weeds growing between block paving. This is because the sand has very few nutrients, which makes it difficult for weeds to sustain themselves. You can also get a specialist version that contains minerals that raise the sand’s PH level and act as natural weed killers.

Dansand is the most popular weed-inhibiting patio sand and maintains its no-grow effect for many years. For it to be effective, your block paving should be at least 4cm tall and have a gap width of 1-5mm.

Is Play Sand the Same as Kiln Dried Sand?

Play sand has not been dried, unlike kiln dried sand, which means it has a higher moisture content. Kiln dried sand flows much easier and will not clump together like play sand. As it doesn’t bind together, kiln dried sand would not compact to make a sandcastle and might not be suitable for sandpits.

How to Store Kiln Dried Sand?

Unopened plastic bags can be stored outside if they are in good condition. However, if they have been opened, or have been torn, then the bags should be stored indoors, in a cool dry place.

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Building Sand
Railway Ballast
Horticultural Sand