HOW TO REPAIR A SINKING PATIO – Is your patio sinking in places? There are a number of reasons why a patio, in certain areas, may sink, including the ground beneath is too soft or the paving slab or paving stone were not laid properly in the first place. A sinking patio is easy to spot, you’ll start seeing slabs or stones that are sticking up at the corners and the appearance is uneven. Don’t worry, this is not a complete disaster, and no, you won’t have to dig up the entire patio. In this guide we’ll walk you through the steps of repairing a sinking patio with easy to follow instructions.
Take a flat garden spade or crow bar and lift the slabs or stones that have sunk. Now remove at one slab from around the problem area. Slabs, depending on the size, can be very heavy, so get a friend to help you. Stack the slabs and stones out of the area you are working with so then don’t get in the way of the preparation work you will be doing.
Take a shovel and remove about 4″ of soil. You should find this fairly easy to do, as the chances are the slabs or stones were not bedded properly in the first place or the ground has become soft.
Pour into the area you have just dug out about 2″ of aggregate and compact this down well. The aggregate will allow for better drainage of rain water and so will help prevent the patio from sinking again.
Once the aggregate is in and well compacted, lay on top of this a layer of builders sand to a depth of approximately 2″. Level the sand using a length of timber with a spirit level laid on top of the timber.
You can simply sprinkle cement on the sand bed and then lay the paving slabs or stones on top. However, if you want a strong bond then, mix up a batch of mortar and place a small spot on each corner and one in the middle of each slab. For stones you can use a trowel to lay a bead of cement across it, in the same way you would if you were laying a brick wall.
Place each slab or stone into place one at a time. Take your spirit level and place this on the top of the slab and make sure it is level and level with the surrounding slabs or stone. If not tap it down, using a rubber mallet until it is level. Repeat this for the remainder of slabs and stones until you have completed the entire area.
Take some sand and cement and mix this together, at a ratio of 1 part cement to 2 parts sand. Mix this dry and DO NOT add water. Spread the dry sand and cement mix over the area you repaired and using a a soft head broom, sweep the mixture into the joints until all the gaps between each slab or stone is completely covered. You can take a broom head and tap in the mixture to ensure that the joints are well filled and compacted with the dry sand cement mix for a better finish.
Sweep off any excess sand and cement mix and leave the slabs or stones to settle for a 1 or 2 days. It’s a good idea if you keep some of the dry sand and cement mix in case the gaps need a topping up after the slabs or stones have settled.
Once the area has settled you should now have a nice even patio surface that you can use without tripping over those slabs or stones that were once sticking up.