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How To Relay Loose Paving Slabs: [Sticking Down Rocking Pavers]

Over time, even the toughest of concrete can wobble – and in this guide, we’ll show you how to relay loose paving slabs safely and securely.

There are all kinds of reasons why a paving slab might become wobbly. However, it always pays to know basic patio slab repair so you can get dangerous, loosened stone back on level ground.

As paving experts, we’ve helped get all manner of shaking, rocking stones safely back in place. It can be a relatively simple job to repeat once you know how to get loose slabs on the level again. That said, you’re going to need the best tools for relaying paving slabs in the first place, as well as a gentle bit of know-how.

In this guide, we’ll take you through:

  • Signs you’ve got an uneven paving slab
  • When you need to start lifting paving slabs
  • How to replace the bed / old mortar
  • Mixing concrete correctly
  • How to re-level patio slabs
  • Taking care of the joints
  • Protecting other slabs and stones while you do

In many cases, relaying patio slabs is best left to the professionals, but if you’ve got a couple of people along to help, balancing and fixing rocking paving flagstones is a skill that’s worth learning. You can absolutely repair a patio yourself – here’s how.

Signs It’s Time to Relay Paving Slabs

You’re going to need to know how to fix loose paving slabs if they start doing any of the following:

  • At least one slab is rocking about or wobbling
  • They’re causing trip hazards
  • They’re moving every time you step on them
  • The stone is on an unlevel surface
  • You’re noticing paving slabs starting to sink

You don’t always need to replace them outright if they’re showing any of the above. However, you will need to pull them up, check out the bed and mortar, and relay them again.

Lifting Paving Stones

Lifting paving slabs will need the right tools – such as a plugging chisel and a spade – as well as a few people on hand to help.

We have a quick, simple guide on lifting paving stones and slabs you’ll want to take a look at before you start fixing the wobble. Be sure to head there before these next steps – lifting patio stones properly takes genuine care.

Replacing the Bed

Replacing the bed is all about taking out your old mortar mix. Once your stone’s out, make sure to grab a lump hammer or rubber mallet and a bolster chisel. You’re going to need to gently tap and chip away at it carefully so as not to disturb the surrounding stones. Precision is more important here than speed, but the job shouldn’t be too painstaking.

You’re then going to need to make sure you have a fresh mortar-cement mix to replace the old bed.

The Right Concrete Mix

Fresh mortar for your paving stone(s) should ideally be 1:4 – so one part cement and four parts of the mixture sharp sand. Try to portion this with the same measure for each part (you might want to add four spades of sand to one spade of cement, for example).

Your mortar should ideally be pretty thick – it’s going to need mixing thoroughly. Anything less than a thick pour is going to be too wet or too inconsistent.

This handy guide shows you the right mortar mix for laying patio slabs.

To stop future wobbles, make sure the mix is levelled off completely. You’re also going to need to pack it down as much as possible, so there are no gaps.

How to Re-Level Patio Slabs

The knack to knowing how to re-level patio slabs is in carefully tapping. Once you have your finished, level mortar surface, you will need to lay your slab gently and then tap across the stone with a rubber mallet to ensure that it’s firmly in place to set.

Re-jointing

Re-jointing is an essential step in patio slab repair, as it’s here where you’ll fill the large gaps. Once your concrete slab is back in place, you need to mix a jointing system into said gaps to complete the fit. It’s essential to keep that trowel handy even when you’re finished with the main mix.

Again, you can create a wet, sharp sand and cement mix, 4:1, for sturdy and reliable jointing. You can, however, also invest in ready-made Geofix jointing or similar compounds. While offering excellent long-term results, this can also be an expensive option.

Some people also choose an epoxy solution for jointing as it can last for several years – however, providing you care for it properly, there’s no reason this won’t work well for you.

Protecting the Surrounding Slabs

When you’re adding a new mortar mix, you are obviously going to want to avoid causing damage to other stones. Start by covering your adjoining slabs so that mortar marks and droppings don’t spray across and set hard.

Why the Sub Base is Important

Your sub-base is part of the steady foundation your paving needs to keep stable and uniform for years to come. Without it, you’re at risk of further wobbling – it’s imperative to lay a sub-base for a driveway, but foot traffic will always need additional support, too.

FAQ’s

Can you lay new slabs on top of old ones?

No – essentially, you’re going to raise the level of your garden if you add patio stones stacking up on top of each other. It’s not only going to look terrible, but it’ll also hit your damp proof course. That could create issues inside and outside of the home.

Glueing broken paving slabs

Not really – there are a few adhesives out there that some tradespeople recommend, but if your slab has a break or a crack, glue isn’t going to get rid of a visible join. It’s likely best to start laying new stones if cracks are big enough in your patio. Sticking down loose pavers with glue is hardly a solid option, either.

Why are my patio slabs not sticking?

Generally, this means you need to need to redo your mortar mix. They may have been laid on a bed that is either too dry or too viscous – it’s essential to follow the mixing steps carefully to get the best consistency for adhesion.

Last Word

Once you know how to relay loose patio slabs and mix new mortar properly, you’ll likely find it a breeze in time to come. Just remember to gather the right tools, lift old pavers carefully, and get the old mortar out from underneath before the new ones are laid. As always, it’s a good idea to have a few people help you with wobbly stones – for the lifting.

Covering surrounding slabs from splashing, too, is a step that people forget quite a lot – so protect your ‘working’ paving slab area before you start your lift.

Replacing patio slabs is crucial if you develop cracks in the stone or rock – it’s safer to get those stones re-laid than to keep walking on uneven slabs. Get underneath that wobbly paving slab, replace the mortar, and relay the concrete.