ARTICLE

How to maintain a patio

If you are sprucing up your garden, your patio probably needs some work, too - is it a little tired or in need of repair? Craig Phillips finds solutions to the most common problems you will have.

How to maintain a patio

How to maintain a patio ,with Craig Phillips

General tips

  • Clean your patio once a year
  • If using cleaning products, always wear safety gear
  • Keep children and pets inside until the patio cleaner has been washed away
  • You can hire a jet wash

Read on for more information about the most common problems with patios and paving:
How to lay a patio
How to lay paving
How to spring clean your patio
Garden design: Patio ideas
Craig's spring maintenance checklist


How to repair a rocking patio slab
First you need to remove the slab without breaking it - a new slab would be a different shade of colour and will stand out. Use a flat bolster and hammer to chip away any loose pointing around all four edges of the slab, then you will be able to slide the bolster down one side to lever up the slab.

Once lifted, dig away down were the slab has been for about 150mm (6 inches), you'll find that this will be quite a soft dig if the slab has been moving for some time.

Lay down some hardcore around 75mm (3 inches) deep, then tamp this down with a thick batten and a lump hammer to get it a good firm base. Sprinkle some sand onto the hardcore and again tamp this down until it’s very firm and level.

Tip: Mix a sand and cement mortar mix, four parts sharp sand, to one part cement (this can be a dry mix or you could add a little water).

Lay it in the area and bed the slab onto the mortar mix. Span a spirit level over the top so it covers the slabs next to the one you’re repairing, and gently hammer the slab down to suit, using the wooden butt end of your lump hammer so you don't crack the slab. (If you have a rubber paver’s hammer, all the better.)

Wait for the mortar below the slab to dry and then repoint around all four sides again using the four to one mortar mix.

How to clean mould, dirt and stains from paving
For cleaning all hard external surfaces like paving, patio slabs, stones, even a concrete yard, you'll need a good power jet wash. To start, brush all the loose stones, leaves and rubbish away so they don't go down your drain.

Next get a tub of stone cleaning liquid. Sika and Everbuild both sell really good varieties.

Before using any of these substances, make sure you wear gloves, goggles and old clothing, and also always follow the manufacturer’s instructions… particularly about how much water to add, as they do differ. Apply to the surface using a hard yard brush, scrubbing away at all stubborn stained areas.

Keep all pets and children away from the area until it’s properly rinsed.

How to get rid of weeds
The best way of preventing weeds is to keep the patio or paving well maintained. Start by trying to remove all the loose pointing from around each of the slabs were the weeds are coming though, you can use an old flat screwdriver or a bolster.

Try to get it out to the depth of the slab, around 50mm. If you have a jet wash, spray between all slabs to get rid of any loose bits.

Next, pour some weed killer down between all slabs, leave for a couple of hours and then pour a second lot down, leave to dry until the next day.

When using weed killer, always follow the manufacturer’s instructions to the letter. Wear the correct safety gear and keep children and pets away from the work area.

Next, you'll have to repoint around all of the slabs using a four to one sharp sand and cement mix. When doing jobs like, it's best to do the whole area as opposed to just patches. It will take longer, buy it will not only look a lot better, and should only need doing around every five years if done properly.

How do I fix a loose edge slab?
This is a very common problem and can make your whole patio look poor. And, if not sorted out, will only get a lot worse. Start by removing all the loose slabs from the edge, and number them with chalk so you can replace them in the right place easily.

Dig out a 150mm (6 inch) trench all the way along were you have removed the slabs. Mix up a lean wet concrete mix, three parts gravel, two parts sharp sand and two parts cement. Lay the concrete into the trench you have dug out, tamping down with a long straight length of timber. Keep the concrete around 15mm lower than the base of the existing slabs. When this is dry this is going to act like a foundation.

Now you can re-lay all of the slabs in the same place, bedding them down onto the new solid foundation, using a wet mortar mix of four parts sharp sand to one part cement.

Can I extend my patio?
Yes, of course you can if you have the spare space! The main issue will be getting matching slabs, but if you can find some that are a good match, or are happy to use a different type of stone and slab, and make it a feature, then why not?

You'll need to clear all the ground where you are going to lay your extended patio, going down around 150mm (6 inches). Treat the area with a weed killer (following all safety advice and instructions), then lay around 100mm (4inches) of hardcore.

Level this and tamp it down firmly, (it may be worth hiring a vibrating plate machine to do this) so your new slabs don't move. Then you can lay the new slabs on either a bed of sand, or a wet or semi-dry mortar mix, as above.

Colour matching new mortar to the old for re-pointing
Sometimes it's hard to get a perfect match for new and old mortar. If your existing mortar has had a coloured dye included when it was first done you will need to chip out a small piece and take it to your hardware store to find the right colour code to match.

You may be better off removing all the pointing between slabs and doing the whole lot!

If you don’t want to do that, your best bet is to mix up small batches of mortar, with different mixes of sand and cement (and any colour dye) and let it thoroughly dry, and find the best match you can.

If you are raking out any of the existing pointing, you will need to remove at least 25mm of old pointing, so your new mix really bed in between your slabs, so it won't come loose in a couple of years.