Patio, Decking & Fencing

How To Lay A Patio

Step 1. Planning your patio

First, decide where your patio is going. Draw a detailed plan to scale and include all the dimensions of your patio area. 

Mark permanent fixtures on the plan – the house, walls, fencing, manhole covers and any trees or large plants. If you don’t want to cut slabs, go for a ‘chessboard’ layout, or one of the ranges that come with half-slabs. 

Your patio must have a gradual slope away from the house to ensure all water drains off. Allow a drop of about 25mm in every 1.5m or install a drainage channel. Allow 10mm-30mm between slabs for fettled edge, natural stone or heavily riven slabs. Leave 10mm-15mm for straight edge slabs.


Step 2. Measuring up

Calculate the area of your patio in square metres. Each pack of paving slabs shows the area it covers. Using a single size slab? Then simply divide the area of your patio by the area covered by one pack to see how many packs you need.

Step 3. Marking out the patio

Accurately transfer your plan to the ground with wooden pegs, a builder’s square and string. 

Mark lines on the wooden pegs to show the depth of working – i.e. the finished level of your hardcore, bedding mortar and patio slabs. 

Make sure the marks for the top surface are level with any existing paving and manhole covers. 

Top Tip: Remember to allow for a gradual slope away from the house when putting in your wooden pegs (see Step 1).


Step 4. Preparing the base

Remove any turf, plants or paving and dig down to a depth of about 150mm to allow for the foundations. 

To lay a solid base for your paving slabs, you first need a layer of hardcore at a depth of about 50mm to 80mm over the area of your patio. Use a rake to distribute the hardcore, evening out any bumps, then add a layer of bedding mortar over the compacted hardcore.


Step 5. Laying down the paving slabs

Before you lay your slabs, check with a builder’s square that the string guidelines are square to the house. If not, simply re-adjust. 

Lay down the first slab against the house at the corner, checking it’s aligned with the string guideline. It’s crucial that the first slab is positioned accurately.

Gently tap the slab to the correct level with a rubber mallet. Use a block of wood to protect the slab. Check the alignment of the slab with a spirit level, allowing for the slope away from the house.

Continue until you have laid all the paving slabs. Then, do a final check to make sure everything is level. 

Top Tip: Buy all your paving slabs at the same time so you don’t get variations in colour and texture!

Step 6. Pointing (filling the gaps between the slabs)

Once your slabs are laid, leave the mortar to dry for at least 24 hours before ‘pointing’ (filling) the gaps between them. This stops your slabs from moving and prevents weeds from growing. 

To make the pointing mortar, use a semi-dry mixture consisting of four parts building sand to one part cement. Make sure the mortar is only just wet – this will prevent shrinkage.

Adjust the mortar consistency by adding more water if it’s too dry or more sand and cement (pre-mixed to the correct ratio) if it’s too wet.  

Press the mortar into the gaps with the edge of a trowel. Brush off any surplus mortar before it’s completely dry with a semi-stiff brush. Finally, wash the slabs with a damp sponge and water to remove any leftover cement. 

Top Tip: If you’re laying your patio in the Summer, make sure the mortar doesn’t dry out too quickly as it could crumble. In colder weather, protect the drying mortar from rain or frost with polythene sheeting. 

Step 7. Maintaining your patio

Before sealing your patio to stop water seepage or fading, check the manufacturer’s recommendations. If the patio freezes, get rid of snow and ice with a plastic shovel or stiff brush. Do not use salt as it could damage the surface.  

Use a pressure washer on a low setting to clean your patio. Point it at an angle facing away from the slabs and don’t use it too close to the slabs or you’ll damage the surface. 

To keep your patio in spotless condition, it’s worth investing in some patio cleaning products. Patio Magic Hard Surface Cleaner is a long-lasting antibacterial disinfectant, allowing for easy removal and prevention of green mould and algae. Similarly, a Black Spot Remover is a simple way to tackle black spots, lichen and tough stains. 

So that’s how to lay a patio! Find more ideas, advice and inspiration for your patio and outdoor space here. 



Writer and expert