How much gravel do I need?
To answer the question – How much gravel do I need?- We need to take a few things into consideration:
- The size of the driveway
- Depth of gravel
- Sub base requirements
- Size of gravel to be used
How much gravel do I need? – Measuring the driveway area
The size of the driveway is the first step. A long reel measuring tape is needed and simply measure the shape. Rectangular and squares are easy but for driveways with shapes and beds remember to subtract these areas from your final measurements!
How much gravel do I need? – Depth of gravel
Ideally, the depth of the gravel should be around 2cms (20mm). Less than this may lead to patches and any deeper may mean losing your leg (or at least your foot) as you crunch through it – a little like going on a shingle beach! So, don’t calculate to deeply! Worse than losing your leg, deeper gravel will lead to ‘rut’ formation.
How much gravel do I need? – Sub base
The existing sub base may have some impact if there is a mixture of soil and stone. It’s tempting to simply lay gravel straight onto soil but a few heavy spells of rain will bring the mud up and cause sinking. Always make sure a solid sub base is laid down. The use of gravel grids is popular and these help prevent the movement of stone and aid stability.
How much gravel do I need?- Size of Gravel
Gravel comes in a range of colours and sizes. Pea shingle is never suitable for driveway purposes unless it’s only being used to walk on. Whether you choose a rounded type of stone or a more angular cut stone is personal choice. The best size is 20mm and you may be able to get away with a slightly smaller size but 20mm works best.
How much gravel do I need? An example
For ease of measurement lets suppose we have a straight forward rectangular driveway with edging restraints and sub base already laid. Our driveway area measures 15 metres by 8 metres. We are going to lay to a depth of 50mm.
Around 3.2 tons will be required. A gravel supplier may deliver a truck load of 700-800Kgs and as a last resort 20 – 25Kg bags of gravel can be ordered. Please note, however that with the example above this would mean around 125 bags. The cost will be more if you order the gravel in bags.
An idea of some costs
River washed type gravel (20mm) will cost £8-10 per 25kg bag.
Black Bassalt (20mm) will cost £10-12 per 25kg bag
Golden Gravel (20mm) will cost £10-12 per 25kg bag
Bulk bags are usually available and these hold around 750kg to 850kg. These are usually delivered in pallets but you may find some delivery services that offer crane offloading.
Choice 1 Gravel Master
Choice 2 Mainland Aggregates
Luckily with gravel there are rarely any drainage issues to think about. Gravel provides the perfect drainage system, afterall.