This article is a beginners guide to laying block paving. It will look at how block paving should be constructed. The good news is that block paving can be done by anyone who is handy enough and has the patience to learn. The bad news is that it is quite hard to master and very time consuming.
Don’t let that put you off tho, building your own block paving can be very rewarding and save you a lot of money.
How much does block paving cost per square meter?
Block paving costs between £90 and £120 per square meter if you want to hire a professional. The materials only make up around £20 per square meter so you could save yourself hundreds or even thousands of pounds by laying block paving your self.
Our guide runs you through exactly how to install block paving. It also includes our expert insider tips to save you time and money.
The first part of the guide covers the basics of laying block paving. The second part looks at laying block paving on different surfaces and the extra steps that need to be taken.
Throughout the guide will suggest time saving tools which we highly recommend.
The area where you want to lay block paving will need to be cleared and leveled before you begin. Block paving needs an even, firm base or it is likely to sink over time.
Work out beforehand how deep you will need to dig in order to lay the block paving. This needs to include the sub base, sand base and block depth. Mark out the area and make sure you have somewhere to dump the waste when it is taken out. You can pile it up and then hire a grab waggon to take it away.
Make sure you have a good spade or the digging our phase can be gruesome. We recommend trench shovels because normal garden shovels are not built for this kind of punishment.
A sub base of crushed rock or hardcore needs to be laid and compacted using a wacker plate. The depth of the sub base depends on what you are going to use the area for. The heavier the usage the thicker the sub base will need to be.
For driveways which will have cars on them it’s a good idea to have 100mm of sub base. For patios you may be OK with no sub base provided the soil is compact and level underneath.
When ordering in type 1 MOT (hardcore) its common that it comes in weights rather than volumes (as unhelpful as this is). To get the weight in (UK) Tons take the volume and multiply it by 2.
Example: for 10 square meters of block paving with a 100mm sub base.
Work out the volume
10 (surface area) x 0.1 (depth in meters) = 1 cubic meter of hardcore
Work out the weight
1 x 2 = 2 tons (2000kg)
If the block paving will be for a patio or a low foot traffic area you may not need a sub base. Compacted soil will generally hold its shape under moderate pressure, especially if the weight is spread by block paving and a sand base.
To test if the soil is firm enough step on the soil with your full weight. If the soil deforms with the pressure of your foot then it is too soft and you will need to use a hardcore sub base.
When compacting the block paving sub base, make sure you go over each area at least 3 times with the compaction plate. If you don’t do this step properly its likely the block paving will sink and settle over time.
The base layer should be made up of 50mm of damp sharp sand which is levelled using wooden rails. The blocks will be laid directly on top of the sand so it needs to be evenly spread and completely level. Use a spirit level to make sure the rails and flatten board are perfectly level. There are spirit levels build for this exact purpose which save lots of time.
The base will be compacted after the blocks are laid so make sure it is 10mm above the desired level.
Block paving needs to be retained by firm edges in order to support the block paving. Any gaps at the edges will mean the blocks can move and sink.
An edge can be a house wall, a concrete border or any other feature which has sufficient strength to hold the blocks in place.
After the sand base is laid its time to put the blocks in. You can’t stand on the the sand base so ensure you have a plan which works for the area you are block paving.
Most block will have spacing nodes which will ensure they are the correct distance apart if you push them as close together as possible. Start from one flat surface and work outwards.
It’s likely you will have some awkward parts around the edges. You will need to cut blocks to fit into these spaces. This can be done with a block splitter or an angle grinder. Both can be rented or bought from most tool shops.
Lay the blocks without worrying about their exact level in relation to each other. After the blocks are all laid, go over the surface again with a whacker plate until they are all satisfactory level. Usually 1 – 3 times will do it.
Tip: Make sure you know what pattern you want before laying or you may have to go back and fix it.
The final step is to fill the gaps in the block with sand. Fine dry sand should be purchased for this. Sprinkle the sand onto the surface and use a brush to sweep it into the gaps.
This stage should only be done when the surface is dry.
This is an entirely optional stage but should be mentioned for its benefits. Block paving can last for decades however it does require some upkeep. Over time the sand in the joints can vanish, leaving the blocks wobbly and uneven. Re sanding the paving once every 2 years is usually enough to stop this. Using a high quality sealant can hold the sand in place which reduces the need to replace it.
Weeds are probably the main issue that we have seen with block paving. No matter that you do, they will find their way into the joint eventually. The only permanent way to stop weeds in block paving is to seal the joints.
If you follow these steps careful you will be left with something to be proud of. Each stage takes some practice but is easy to pick up. Block paving can be used as soon as it is completed so you can enjoy it immediately.
Block paving should never be laid directly onto soil. Soil will not compact in an even way under the blocks and will result in an uneven surface. However, if you are block paving a patio you don’t need to go too deep into the soil with the base. If the soil is firm then you can just use a sand base and skip the crushed rock sub base.
Summary: skip the sub base step above and follow the rest of the process as normal.
Lots of us have sloped gardens and driveways which are impractical to level. We still want them to look good and be useful. Laying block paving on a slope can be done but involves some extra work.
Block paving is held together by tension and gravity. This means that if there is any room to move, the structure will be compromised and the blocks will move over time.
When laying block paving on a slope the number rule is to make sure the slope is uniform. If it is steeper at one end than that the other there will be areas where the blocks are not connecting properly. Over time the sand will shift and the blocks will move.
If you have an uneven slope in your garden you may need to get it leveled before installing block paving.
A second option is to install midway restaining courses. This means inserting concrete barriers at points throughout the block paving. By doing this you will keep the blocks in each section compact. It also means if there is slippage it will be much easier to fix because it is confined to one section.
Concrete can be a great replacement sub base for block paving. Providing your concrete surface is uniform and reasonably level you can treat it as you would a compacted sub base.
If your concrete is in poor condition with large holes or it is starting to fragment you will need to remove it and start again. Damaged concrete will create an uneven sub base which will eventually distort the blocks.