Material | Quantity Guide |
Paving slabs - Concrete, natural stone or porcelain. | Measure the area in m2 and add 10% to account for any cuts or breakages. |
Type 1 MOT hardcore - A sub-base aggregate. | 1 tonne will cover roughly 6m2 at a depth of 100mm. |
Sharp sand - A bedding mortar component. | 1 tonne per 15m2 covers a depth of 40mm. |
Cement - A bedding mortar component. | 1 bag for every 3-4m2 of bedding. |
Jointing compound - Brushed-in or slurry type depending on your chosen slab. | 1 pack per 5-10m2 depending on the width of your joints. |
Weed membrane - Optional for your sub-base. | Same as the area of your patio. |
We also shouldn’t forget the tools you need for laying a patio. Make sure you have all these items handy before getting started:
Measuring tape and string lines
Wooden or metal pegs for the string outline
Folding builder’s square
Spade or lawn edger
Rake and hand tamper
Spot board and mixing paddle
Brick and pointing trowels
Rubber mallet
Spirit level
Wooden spacers or tile spacers
Bucket and watering can
Angle grinder with diamond masonry blade
Don’t forget to don the right safety gear too, including safety boots, gloves, dust mask, goggles and ear defenders.
How do you prepare the ground before laying a patio?
Ground preparation is where most people let themselves down on a DIY patio, so don’t be tempted into rushing this stage. Here are the key steps:
Check for underground services - You can use a specialist Cable Avoidance Tool (CAT) to detect any underground obstacles, such as cables, before starting.
Mark out and excavate - Use pegs and string to mark the perimeter of where you want your patio to be. You can then dig this area out to 200-250mm depending on slab thickness, removing any lawn, topsoil and root material to avoid settlement issues.
Check the fall - Work out your drainage gradient now, not once the sub-base has been laid. You should ensure the surface will fall away from any building at a 16-17mm per metre rate. Gradient pegs can help, and if you can’t fall away from the building, you may need specialist drainage assistance, as water against your DPC risks serious damp issues.
Compact the sub-base by layers - Add your Type 1 MOT hardcore in two layers, roughly 50-75mm each, compacting the first before adding the second. This provides proper consolidation and ensures you don’t get an uneven finish later. You should be able to stamp the compact surface without it giving or moving underfoot.
How do you lay and finish patio slabs correctly?
Only now can we move to the laying sequence, which is as follows:
Step 1 - Mix your bedding mortar, 4 parts sharp sand to 1 part cement. This mix should be just about damp enough to hold its shape; it should not be wet. Wet mortar will compress when you lay the slab, which loses your level.
Step 2 - Lay your first slab, starting with the highest corner, closest to the house. Your bedding mortar should be 40-50mm deep for each slab at a time. Give the underside of each slab a quick dampen, set it down into position and then tap it firmly with a rubber mallet.
Step 3 - Check the level and fall, ensuring each slab is positioned correctly for the drainage direction. You can check this with your spirit level after each slab is laid.
Step 4 - Work in rows and apply your spacers between for consistent gaps. Guessing your spacing will make your joints look wrong, and it can be harder to point them neatly later.
Step 5 - Check your string lines regularly, as alignment can shift over a large area if you’re not paying attention.
Step 6 - Don’t walk on your freshly laid slabs for at least 24-48 hours. This gives time for the bedding to cure without shifting and destroying your careful levelling.
Step 7 - You can now point your joints once curing has finished. Brush in a dry jointing compound for standard slabs and apply a slurry pointing mix if you have wider joints of over 12mm. Sweep away any excess compound and protect the slabs from rain for the next 24 hours.
Looking for all the materials you need for laying the perfect patio in your back garden? Then check out our online store where we stock everything from Type 1 bulk bags to beautiful natural stone paving slabs.
Our products are available for free delivery across Essex, Suffolk, Norfolk and Cambridgeshire when you spend over £20. If you’d prefer to browse and pick up items in store, visit one of our branches today.
Frequently asked patio laying questions
How long does it take to lay a patio?
On average, a 20m2 patio, including the full sub-base preparation, would usually take two people a full weekend. This accounts for one day of excavation and sub-base preparation and one day for laying, with half a day for pointing once slabs have cured in place.
Do I need planning permission for a patio?
Most residential patios in a back garden won’t require planning permission. The rules differ for the front of your property, however, where permeable paving and drainage into soakaways is preferred if you’re going to lay slabs.
What is the best base for a patio?
100-150mm of compacted Type 1 MOT hardcore is considered to be the industry standard. Depending on the type and size of stone you intend to use for your patio slabs, you may need to research whether further preparation is needed.
How do I stop weeds growing through my patio?
Properly filling in your joints is the first line of defence. You can dry-brush jointing compounds into your joints that set and don’t leave gaps, but a weed membrane below the sub-base is another way to prevent weeds from ruining the perfection of your newly laid patio.
