Average Labour Cost/Price to Lay a Patio, Slabs or Paving
Lets keep it simple. A rectangular foot traffic only patio, just below lawn level across the back of your house. So that’s 6.5 metres wide and 4.5 deep. There’s an old path there at the moment, the rest is lawn and it goes right up to each side fence. You have found and paid for the slabs in the local merchants, he is organising delivery along with the stuff he needs
This will take 2 men, 5 days to dig out, dump the turf and topsoil on a tarp in the garden, lay and compact the foundation which will include the broken up path, lay the slabs on dabs of muck (mortar) cutting a few at the edges, brush in the pointing and hold their hand out for payment.
Materials including the slabs and hiring the “whacker” £825, Labour £1300 £2125.00
Same job but the garden slopes down so you want a foot high retaining wall at the lawn end with what will always be an annoying little step in the middle. The wall will continue at the sides back to the house and have copings all round. He still has to dig out, there’s the wall’s foundation to lay and you can’t just lay hardcore on the lawn. He will also need a lot more of it. This will take 2 men 7 days.
Materials £1100. Labour £1820, £1820.00
Same as either of the above but you have decided you want different sized slabs and a circle in the middle. This will take longer and you will have slabs left over because no one knows how many of each kind you want until the last one is laid. He will also have to go back to the merchants to by the ones he needs to finish off with.
He will hate you for this, so will charge an extra day and a half, so add…. £400.00
Information about laying a patio:
Just like floor tiling outside really, except there’s a lot more muck to shift. Actually you can make a patio on the lawn if you want, just by laying slabs on top, it’s quick and will take ages before it starts to trip you up. You can even mow between the slabs with a hover, (and they call builders, cowboys)!
If you want a proper job though, first you have to decide what’s going on it. If it’s the car, then the foundation will have to be a lot stronger than if it’s just going to be the usual table, chairs and you lot.
We’ll deal with the car later. For normal foot traffic and a patio you want to last 20 years, sited where the lawn is now, you will need to remove all the topsoil down to about 200mm (8”). This will have to be put somewhere and it’s a shame to chuck it away in a skip so at least ask the builder to leave it in a pile on an old tarpaulin so you can lovingly sprinkle it between your roses over the next 2 weeks. Don’t ask him to do it, builders don’t do “lovingly”. You might even save the turf for something.
If there’s an existing (concrete) path in the way, get this broken up and laid to one side don’t chuck that away. A very important matter for consideration is the finished patio level, particularly if it’s going right next to the house. No finished paving height should be higher than 3 courses of brickwork below the building’s damp proof course, (that’s about 230mm or 9”). (see our section on Rising Damp if you like). Also a patio laid right up to the house should really have a slight slope away from the building.
If there are existing slabs, or concrete, or even tarmac and if it’s low enough, it may be possible to lay the new patio straight on top and simply treat the existing surface as the compacted hardcore. This depends on what the existing one is laid on and how unstable it is. There must be something wrong with it or you wouldn’t want a new one! Ask the builder, it could save you a lot of money.
Talking of levels, if you intend to lay a lawn right up to the edge of the new patio, make the lawn about 25mm (1”) above it, then you can mow the lawn right up to the patio edge, (over it in fact). If you don’t, you’ll be for ever strimming the last bit of grass.
The longest lasting foundation for a foot traffic only patio, will be to backfill the new excavation with about 150mm (6”) of rubble that’s broken up to about the size of an egg. You can use the old path for some of this. This should be well compacted down with a vibrating plate (that’s a machine, not what your dinner does when the wife’s doing the vacuuming), to about 100mm depth (4”).
The patio slabs are then laid on this with 5 dabs of mortar underneath each one. This will allow the slab layer to level them nicely and the whole lot will never move. If he does use dabs, make sure the builder wets the bottom of each slab with a strong PVA solution first, this makes the mortar really stick.
Another way is to lay “sharp” sand on the compacted hard core, compact this, level it out and lay the slabs directly on top. There are several types of sand, sharp is best for slabbing.
The hardcore doesn’t have to be rubble, it can be “scalpings” or “hoggin” which are both gravel mixed with clay, or ballast, which is sand and gravel mixed. The main thing is that it’s compacted.
There are several ways to grout a patio. The most common and quickest is to brush in a 4:1 mixture of playpit sand and cement powder, this is all done dry. Playpit sand, unlike other types, arrives bone dry in the bag.
The idea is that ground water or light rain will soak into the mix and set it hard. We usually give it a very light sprinkle with the hose though, once the slabs have been brushed completely clean. This starts the setting process off because if it rains hard before it can set, it all gets washed out, sets on the new patio and to quote Forrest Gump “Eustace, we have a problem”. Sand, on its own, is useless and just washes away.
Ideally though, grouting should be done with almost dry mortar “chopped” into the gaps and trowelled smooth. Almost dry because it won’t mark the slabs and the trowelling will bring it up nice and smooth and shiny. You do need a very thin blade though, an old galvanised bucket handle is perfect but only old galvanised builders still have one in their kit.
If the car is to be parked on the patio, first of all it will be a car port and secondly where will you lot sit?
The difference here is the foundation, you have to go about 75mm (3”) deeper with the hole, lay concrete directly onto the compacted rubble and forget any sand. The slabs have to be laid on dabs of mortar on the concrete.
Retaining or Edging Walls etc.
If you are slabbing on a slope, unless you want a sloping patio, you will need a retaining wall. Have this built first on a good concrete foundation and thick enough to hold back the stuff behind it. Don’t leave the top as just normal brickwork, have a “coping” put on top, or a brick on edge.
Concrete “curb” panels are a good idea up against a patio edge which is to have soil on the other side. This allows the soil border to be higher than the patio. The panels are about a metre long, 50mm (2”) thick and 150mm (6”) wide and they are laid on edge, alongside the patio slabs. This allows the garden to begin about 75mm (3”) above the patio…. perfect!
Galvanised strip drains can be incorporated into a patio’s surface if necessary. They can take the water to a soakaway or an existing gulley (drain).
All the different bricks, plus the other stuff, plus of course all the different patio slabs themselves can be looked at and chosen before you call the builders in to quote. Probably your first port of call would be a garden centre or DIY shed but a good builder’s merchant will stock a large selection as well.
Builders are far more used to dealing with merchants, may have an account there and transport is far easier to arrange. If you go to a merchant, do it during the week at 10 am. Saturdays are always crowded with bloomin civilians like you asking hundreds of daft questions and clogging the whole place up. Every self respecting builder is in the “caff” at 10 during the week, so you will have the place to yourselves and can ask your hundred questions without holding up the builder when he gets there at 11.
The vast majority of patio slabs are about 450mm square, made of concrete and are tinted. There are variations of course, you can buy tinted concrete slabs that come in about 4 different sizes so you builder can play with different designs……He’s just dying to do this!
For 30 years as a “London” builder I was never asked to lay anything else. Now, I live in deepest Yorkshire and my garden terrace is slabbed with “flags”. These are stone, they come in different sizes (so I could practice my tessellation), unlike concrete slabs these different sizes are determined by……. God I suppose! They are new, cheap, “the dogs” and they come from India. Get on the internet and find the supplier, they make those horrid concrete ones look, well….. horrid!
Questions to ask the builder during his quotation visit.
Can you please make sure your quotation states what foundation material you are using, how deep it will be and if it’s then being compacted?
If it’s written down, he will be more inclined to actually do it!
Do you think there should be a drain?
Usually this isn’t necessary, sloping away from the house onto the garden is enough but what if you are covering a small yard, with no garden? Or the patio is huge? The water can disappear into a soakaway, at least get him to tell you how much extra it will cost.
Who is buying and collecting/organising delivery?