To lay paving slabs is a skill which we believe will need to be perfected.
With the compacted sub base already prepared (see here), consideration can be given to laying your chosen paving.
Stretched brick lines between fencing pins must be accurately set out to mark the edges and levels of the paving – make sure that you take the trouble with this procedure (as a mistake at this stage is costly). Check for dimensions and levels – allowing for a reasonable drain on the paving surface into a linear drain or onto the garden.
You will need a 4-to-1 course sharp sand to cement mix ratio with a little plasticiser (or plasticizer) added during mixing. So for example a 12-to-3 cement mix ratio in the cement mixer, with a cap of plasticiser, will fill a builders barrow sufficiently to make a useful amount, thus allowing a few slabs to be laid (depending of course on the thickness of the bedding mix).
It is important to get the mix just right (in consistency terms) for laying your paving.
Too wet – and the paving will just slide and float around with a tendency to sink. Too dry – and the slab might crack whilst being settled into position (with a mallet) and probably will not stick onto the mortar. The idea is to most definitely stick the paving down!
A hint for getting the ‘muck’ just right is to watch as the water is added – just enough to get the mix folding but not flowing whilst in the mixer. The plasticiser helps a lot with the workability of the cement by introducing air – which makes it more slippery and easier to squash down when laying the paving.
Getting the mix right is an important aid to a successful days paving and a competent assistant who understands this can make all the difference. As always, attention to detail even at this stage reaps rewards.
So the next thing to do is to tip the 1st barrow of cement mix out where you want to start (always in a corner and along a stretched line). Using the back of a metal rake, spread it out onto the compacted sub base, squeezing out the air and pushing the muck into the nook and crannies – a barrow load might do roughly a square meter of paving.
Judge roughly what thickness to spread it out to – getting this right is tricky, but this will very quickly become second nature (however it may at the first take some getting used to). Make sure that you are patient (most people with general practical skills can pick this up).
Next, using a brickies trowel, score a couple of deep lines in the mix the in the area of the 1st slab – this will allow air to escape when tapping down your slab and thus compressing the mix.
Lay the slab on the prepared mix, against a line (or lines), tap down with a rubber mallet or club hammer using the wooden handle. Making sure that you tap gently and mainly in the centre of the paving – watching the slab edges against the lines all the time.
Lay the slab to the correct height and level. The mix should ‘squeeze’ out .
Clean up as you work, removing and washing down cement stains that have transferred onto the paving.
Leave the required pointing gaps, be thorough and workman-like at every stage checking alignments’, levels and pointing gaps.
(c) Copyright 2013, Mark Cook, All Rights Reserved. Written For: gardenconstruction.net