You should always dry lay your patio first, before you get to work, this isn’t a difficult feat but simply involves laying the paving out exactly as you want it to be when you’ve completed the job. Size and layout are big factors to look out for, but the most crucial step here is to make sure you won’t be short of paving slabs!
The First Step: Layout Of The Patio Foundations
For foundation mix and paving you should allow 150mm. When laying directly beside the house the completed patio needs to be a minimum of 150mm depth from the damp proof course. In practicality, this calls for you to dig a 300mm minimum depth below the damp proof course.
A fall of 1 in 60 is required to eliminate the problem of water gathering on the paving, this means one centimetre of fall is required for every 60 centimetres of width. For example, a 50mm (5cm) would be required for a patio which is 3m wide.
The Second Step: Foundation Base Preparation
A concrete mix of 1 part cement to 6 parts all-in-one ballast will create a firm foundation. You want the mixture to just bind and no more, so mix and add enough water to reach this consistency. Next, to a depth of 75mm, get the whole area covered, using a shovel to level the surface. Use a length of wood, or simply your boots, to trample the surface down.
The Third Step: Preparing The Mortar
You want the whole slab, not just the corners, to be supported, so lay the paving slab on a full mortar bed. The mortar mix should consist of 1 part cement and 6 parts sharp sand. Add just enough water to create a damp and malleable mixture, without allowing it to become runny.
The Fourth Step: Time To Lay The Paving
In order to guide the line and level of the paving you need two taut string lines set up. One of the lines should run from side to side, while the other runs the length of the patio, make sure one of the lines has the drainage fall. Begin the process at a corner, gradually working your way out. Use the mortar to create an area that is a little bigger than the planned paving slab, it should also be an adequate height to allow you to tap the flag down to reach the right level. Next, being very careful not to catch any of the corners, lift the slab and lower it into place.
Now begin to tap it down using a rubber mallet. Use your imagination to create diagonals halfway from the middle of the paving slab and the corner, this is the spot you want to hit with the mallet aiming for a firm, yet not too strong, strike. Do this for each corner, Tapping each point in turn and continue the process until the flag has nestled down and is sitting at the correct level. Use a spirit level to check that the paving is level and also ensure that you have a fall, once these factors are confirmed, continue with the rest of the paving, when necessary leaving joints. Once all of the patio has been completed, it needs 24 hours to fully harden, hence it is important for no one to walk on the paving.
The Fifth Step: Time To Get The Paving Jointed
Create a smooth, but not sloppy, consistency using 1 part cement and 3 parts soft building sand. If you want to make life a little easier use a plasticiser.
Next it’s time to trowel the mortar into each joint, make sure you press it down, if it seems necessary use a pointing bar to smooth it out. This step calls for extra caution to make sure you don’t get any mortar on the paving slab. It is possible to scrape mortar off the slab, but you should wait a few hours until it has begun to harden.
Check that the mortar has fully hardened, then give the patio a thorough brushing – all that’s left to do after that is give yourself a pat on the back for a job well done!