Paving needn’t be restricted to boring grey slabs. Make the most of the latest designs and a few imaginative techniques to create a great looking area for relaxing outdoors.
If you have just moved into a new home or are planning a major garden facelift, spend time getting to know the site before designing the paved areas. For example, which parts of the garden are sheltered from the elements and overlooking properties? Where does the sun fall through the day? Is there a slope?
Planning the patio
The next stage is to draw up a plan of the garden on graph paper, with trees, shrubs, walls and other fixed features shown. You don’t have to be too exact but an accurate plan of a large project like a patio is the best way of estimating how much material you need, so it’s time well spent.
Paving has come a long way in the last ten years and there are now styles to suit anything from a cottage garden to a formal town lay-out. Remember too that flagstones can be expensive and a hard-wearing lawn or shingle is a cheap way of filling areas of a new site for the short term – you can always replace these areas with more exciting options at a later stage.
Remember to include some sort of paving to storage sheds, even if it is just stepping stones. Otherwise, grass will soon become mud in the wetter months.
Plan for features you may want to add later. So if you are considering a built-in barbecue, pond or planter, leave a space in whole pavers or slabs so you don’t have too much upheaval when these are added.
Break up large areas of slabs with straight runs of bricks or leave out random slabs and fill with shingle to add interest.
Before actually starting any work, make sure you check that there are no services, i.e. pipes, cables etc. buried in the area.
Setting out the patio
Mark out the site with pegs and string. The pegs should be driven into the ground so that their tops are at the height of the proposed finished level. By setting a peg in each corner, you can then build up a grid of pegs according to how large the patio is.
The level of the patio at the house wall must be at least 150mm below the damp proof course. This is usually visible as an extra wide line of mortar in the brickwork or, in older houses, you may be able to see the slate used. If your patio is built higher than this, the walls will get damp.
Fall or slope for drainage
The patio will need to have a gentle slope away from the house (1:40 for most circumstances) so that rainwater does not pool on it. For large patios, you should also have a cross fall of 1:80 to improve water run-off. Use a straight timber batten and sprit level resting on the pegs to get the level. A useful tip here is to work out what the fall should be between the pegs concerned and then place an appropriately sized offcut of wood on top of the peg. When the batten between pegs is level, this offcut has then accounted for the necessary fall.
By measuring down from the top of the pegs, you can establish how much soil to dig away – enough for slab thickness plus the various layers of the base. String lines connecting the pegs will assist with this.
Digging out for the base
Dig out the topsoil and save for elsewhere in the garden. How far you dig down below the topsoil will depend on the patio. For light use, the slabs can be laid on a compacted 50mm bed of sand. More stable, and recommended for most patios, is a 50mm semi-dry mix of sand and cement.
Areas of heavy use should have a compacted 75mm layer of hardcore below the sand/cement mix. For vehicle use, the hardcore bed should be 150mm. Hardcore is broken brick and rubble, which is laid over the ground and compacted to provide a firm stable base. The area of the patio multiplied by the thickness of hardcore needed will tell you the volume of hardcore required, but remember to allow a bit extra as it will be compacted.
It is worth hiring a plate vibrator for the preparation stage to ensure that the base is very solid. Once you have prepared the base, begin to lay the flagstones in one corner.
Laying the slabs
For light use, trowel five generous dabs of mortar on to the base and lay the first slab in place. Tap the surface of the slab with a rubber mallet or with the end of a club hammer and check with a spirit level in both directions remembering to allow for the fall. This is where the string between pegs really helps since you can use it as a guide.
For heavier use, the slabs should be laid on a continuous bed of mortar, 50mm thick, rather than dabs. This way, the slab is fully supported and will be less likely to crack.
You can also lay paving directly onto the sand. This will need to be carefully levelled to support the slabs fully. By putting battens at intervals in the sand, with their tops at the appropriate level, use a straight edge to level the sand between them by drawing it along the battens. Remember to remove the battens and back fill the groove with sand before paving over as the battens will rot if left in place.
Lay the next slab. Some paving can be butted together but there will usually be a 5-10mm joint. Cut pieces of hardboard to use as small spacers and wedge them between the paving to keep this gap even.
Continue to work across the patio area, regularly checking the level. It’s best to work across along the house wall first, then down one side using the guide string before filling in the middle, working diagonally.
Cutting the paving stones
It is usually easiest to leave the slabs which need to be cut until the bulk area has been laid.
Now, fill in gaps with cut slabs. You can use a grinder or bolster chisel to score all around the slab. Angle grinders can be hired. Always read the operating instructions and if you are unfamiliar with the equipment, ask for a demonstration. As with all cutting work, wear safety goggles. Protect your hands with work gloves and with noisy equipment, wear ear defenders. Once scored, raise the smaller section on a thin batten and tap the main part of the slab along the cut line with the handle of a bolster hammer.
Finish off by forcing a fairly dry mortar mix into the gaps with a trowel and brushing off the excess before it dries.