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How to lay porcelain paving slabs

How to lay porcelain paving slabs

Posted on 24 April, 2023

Porcelain paving slabs are a popular way to enhance your garden, they can add a modern and practical feeling to your home, especially if it’s an older one.

Whether you’re just someone who practices DIY as a hobby, or you work in a trade, this guide can help you through the steps of installing porcelain paving slabs into your home.

As well as adding the modern feel, porcelain paving slabs, they’re also highly resilient, and stain/frost/moss proof. As well as these benefits, paving slabs typically require very little maintenance, you’ll just need to clean them using a power washer.

The right tools for the job

Before you start laying your porcelain paving, it’s important to ensure that you have all the tools you will need.

Here’s a list of the tools required to lay porcelain paving slabs:

As for the materials you will need:

  • All In Ballast
  • Type 1 MOT or GSB (general sub-base) stone
  • Concreting sand
  • Slurry primer and SBR additive
  • Flexible grout

Preliminary measures

Now that you’ve gathered all your tools, it’s vital to check over the porcelain paving slabs to ensure there’s no breakages or edge chips.

You should also do a rough layout of the proposed patio by gently placing the paving tiles up to where you plan the finished patio area to be.

If you don’t have enough slabs to complete your project, you’ll need to purchase some more.

Step 1: Digging out

The first step of step 1 is to mark out the excavation area using your string line and pegs with an allowance of 150 to 200mm for kerbs and haunches if the patio edge doesn’t adjoin your house or garden wall.

Next, use your shovel to dig out a total depth of at least 160mm below the planned patio area. A 160mm depth will facilitate 100mm (minimum) of MOT or GSB material, a 40mm (minimum) of bedding mortar and the thickness of your porcelain paving slabs, which is typically 16mm to 20mm.

In the UK, our building regulations state that the paving surface needs to 150mm below any damp proof course to protect your house from damp. As well as this, a fall for water drainage will need to be in place. 15mm for every 1000mm.

This can be achieved by using your string line to guide an alignment.

Step 2: Sub-base

As mentioned, the sub-base that you’ve made an allowance for in the depth gives your patio a stable and secure base. Create an even layer of 30mm below the string line, and then use your compactor to merge the aggregate to a compressed height of 50mm.

Step 3: Bedding mortar

Using a mixer or mixing bucket, it’s time to mix the bedding mortar. You need to use 4 parts of sharp sand for every 1 part cement. Make sure you add the SBR to aid the bonding process.

Next, using your shovel or trowel, add the mixed mortar to the sub-base. Ensure it’s levelled out 15mm below the string line. The bed needs to be full.

Step 4: Priming the paving

You could argue that this is the most important step whilst laying porcelain paving slabs. This is because porcelain has a low water absorption value, and therefore will barely absorb anything from the bedding mortar.

This is why you will need to use a priming slurry to achieve a good bond. Priming slurry is powder-based and is mixed with water to form a slurry paste. Apply the paste to the underside of the porcelain slabs until you have an even coat.

Step 5: Laying the paving and jointing

The final steps for laying porcelain paving slabs are as follows.

Lay down your paving slabs on the mortar bed then use your rubber mallet to tap down on them. You may have to adjust the paving to ensure it is fully supported. You can use your string line and spirit level to track the level and fall of the slab.

When you cut the joints, use the diamond blade that was listed in the “right tools for the job” section.

Once you’ve finished cutting, use a good, flexible grout to achieve a good bond and professional-looking joint.

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