How to Lay Patio Slabs

Considerations before laying patio slabs

Before starting any patio installation, it’s important to assess the site and plan the job properly. Here are a few key considerations to bear in mind.

• Ground conditions: Soft or uneven ground may require deeper excavation to create a solid base.
• Patio use and size: A small seating area might only require a simple square layout, while larger entertainment areas may involve more complex shapes or patterns.
• Suitability of slabs: Confirm whether paving slabs are the best option for the project. Alternative materials such as gravel or decking may sometimes be better suited to certain ground conditions or garden styles and sizes.

How long does it take to lay a patio?

The time it takes to lay a patio depends on the size of the area, ground preparation requirements, and how much experience you have in installing patios.

For an average-sized garden patio, most experienced tradespeople can complete the job in two to three days. Larger patios or more complex layouts will naturally take longer. First-time installers should also allow themselves extra time throughout the process to ensure it all goes to plan.

When is the best time of year to lay a patio?

Patio installation is best carried out during mild, dry conditions. Spring and early autumn are ideal, as the ground is usually workable and temperatures are most suitable for mortar curing.

Wet conditions can make excavation and compaction more difficult, while freezing temperatures can prevent mortar from setting correctly. On the other hand, very hot weather may cause mortar to dry too quickly, which can weaken the bond between the slab and its base, leading to cracks and movement.

What do you need to lay patio slabs?

Before starting, make sure you have the right equipment and materials ready. Below are some of the most important tools and materials required.

Tools for laying a patio

• Spade or shovel
• Wheelbarrow
• Tape measure
• Spirit level
• Rubber mallet
• Brick trowel
• String line and wooden stakes
• Plate compactor or hand tamper
• Bucket or mixing tray
• Stiff brush for pointing.

Materials for patio installation

• Paving slabs
• MOT Type 1 sub-base aggregate
• Sharp sand
• Cement
• Clean water
• Pointing compound or mortar
• Joint spacers (optional).

How to lay patio slabs: Step-by-step

Follow these instructions to achieve a professional, durable finish on your slab patio project.

3. Lay the patio base

   Spread MOT Type 1 aggregate across the excavated area to a depth of roughly 100mm.

   Then, compact the material thoroughly using a plate compactor or hand tamper. This creates a firm, stable foundation that prevents future movement.

   Once compacted, add a thin layer of sharp sand to help create a level surface ready for the mortar bed.

4. Mix the mortar

   The paving slabs are laid on a mortar bed, which secures them firmly in place.

   A common mix ratio is four parts sharp sand to one part cement, with water added gradually until the mixture reaches a workable consistency. The mortar should be firm enough to support the slab without spreading excessively.

   Mix the mortar in a bucket, mixing tray, or wheelbarrow using a shovel or mortar hoe, adding water slowly until the correct consistency is achieved. Mix only what you need in manageable batches to prevent the mortar from drying before use.

5. Lay the slabs in place

   Spread a full mortar bed where the first slab will sit using a shovel or brick trowel, ensuring the mortar covers the area evenly.

   1. Lightly dampen the back of the slab using a sponge, brush, or a light spray of clean water to improve adhesion.
   2. Carefully place the first slab onto the mortar bed. Starting at the edge of the mortar bed is usually the best option.
   3. Use a spirit level to check the position and gently tap it into place with a rubber mallet.
   4. Continue laying the remaining slabs, using spacers to maintain consistent joints.
   5. Once all slabs are laid, leave the patio undisturbed for around 48 hours to allow the mortar to set.

6. Point between the slabs

   Mix the pointing mortar or compound according to the manufacturer’s guidance.

   1. Fill the joints carefully using a pointing trowel or brush-in compound.
   2. Smooth the joints and remove any excess material from the slab surface.
   3. Allow the pointing to dry fully before regular use.

Patio maintenance tips

A slab patio doesn’t require much maintenance, but regular care will help it stand the test of time. Remember these tips to keep your patio in good condition:

• Clean patio slabs regularly to remove dirt, leaves, and debris.
• Occasional pressure washing can remove algae and staining, but use moderate pressure to avoid damaging joints and weakening bonds.
• Remove any weeds that appear between joints to prevent them spreading and cracking slabs or mortar.
• Some paving materials benefit from sealants that protect against staining and weathering.
• Over time, pointing can deteriorate. Replacing worn joints helps maintain the strength and appearance of the patio.

Find the materials you need for your patio project

Jewson provides a wide range of landscaping products suited to professional tradespeople and DIY enthusiasts alike. Explore our range to find everything you need to plan and build a long-lasting patio.