Always dry lay your patio first, a simple job of laying out the paving as you want the finished patio to be. Check size, layout and more importantly, that you have enough paving slabs!
You need to allow 150mm for foundation mix and paving, and if you are laying directly next to a house then the finished patio should be at least 150mm below the damp proof course. This means you will need to dig out the area to a minimum depth of 300mm below the damp proof course.
To ensure that water does not collect on the paving, the foundation needs to have a fall of 1 in 60, which means one centimetre of fall for every 60 centimetres of width. So a 3m wide patio will need 5cm or 50mm of fall.
STEP 2: Preparing foundation base
To create the firm foundation, use a concrete mix of 6 parts all in one ballast with 1 part cement.
Mix and add enough water to dampen the mixture just enough so it binds together.
Cover the entire area with the mix to a depth of 75mm, level it out with a shovel and then tamp down using a length of timber or trample down with your boots.
STEP 3: Mortar preparation
Lay the paving slabs on a full mortar bed, which should support the whole slab, not just the corners.
Use a mortar mix of 6 parts sharp sand to 1 part cement.
Mix together with just enough water to make it damp and workable, but not overly wet and runny.
STEP 4: Laying the paving
First set up 2 taut string lines to guide both the line and the level of the paving. 1 line should run down the length of the patio and the second line side to side, with one including the fall for drainage.
Start from the corner and work your way out from there.
Spread out mortar to cover an area slightly larger than the paving slab you want to lay and high enough to allow you to tap down the flag to the correct level.
Lift and lower the slab into place careful not to catch the corners.
Using the rubber mallet, start to tap it down. Hit the paver, firmly but not too hard, at a point that is roughly midway between the centre of the paving slab and each corner along imaginary diagonals. Move around the paving, tapping in succession until the flag settles down to the correct level.
Check the paving is level with a spirit level and that you have included a fall, then start to lay the rest of the paving, leaving joints as required.
Once laid, the patio should be left for around 24 hours to allow the bedding mortar to harden and should not be walked on.
STEP 5: Jointing the paving
Use a mortar mix of 3 parts soft building sand to 1 part cement and mix it slowly adding a little water at a time to get a smooth, damp consistency - not wet or sloppy. A plasticiser can be added to make the mortar easier to work.
Trowel the mortar into the joints, pressing it down and smoothing over using the pointing bar if necessary.
Take care to avoid any mortar going onto the surface of the paving slab. Surplus mortar can be scraped off, but its often best to leave these bits for a few hours until the mortar has started to harden.
Once the mortar has hardened, all you need to do is give the patio a good sweep - then that’s the job done!
As a reminder, follow our four tips for success:
- Always dry lay the patio first to ensure you have checked the measurements
- Create a good solid foundation and check the depths
- Start laying the patio from the corner and work outwards
- Check the levels and fall frequently to make sure you stay on track