Paths and drives may be built to last, but knowing how to repair paths and driveways can save you a lot of expense because they take a battering from the weather, cars and general foot traffic. Small faults can quickly turn into large ones, so put them right before things go too far.
RE-LAYING PAVING STONES
Paving stones are ideal for paths, patios and driveways, but if the ground beneath them settles once they are laid the stones can sink unevenly. And if they have to take the weight of a car, stones will break unless they are properly supported.
If a stone sinks or breaks, it must be removed and relaid or replaced. Path and patio pavers can be relaid on plain sand — simply add more to make up the difference in level. But if the stone forms part of a driveway, it is best laid in repair mortar preferably on a solid bed of homemade hardcore.
1. Lever out a sunken stone with a garden spade (broken ones can be chopped out with a bolster or cold chisel). If there are clear signs of subsidence, ram hardcore — small pieces of rock, brick or concrete will do — into the ground to compensate.
2. On a patio or path pour more sand into the hole, concentrating it at the corners and the middle. Lay the stone in place and tap it down with a piece of wood.
If the stone needs to be laid in mortar, buy a bag of readymix or make up a strong mix of one part cement to three parts sand.
3. Score channels in the sand or hardcore base so that the mortar settles properly when you bed down the stone.
Once the stone is laid, leave the driveway for at least 24 hours — longer if possible —before you run a car over it.
In both cases, any mortar pointing can be replaced with a fairly dry mix of 1:3 readymixed bricklaying mortar. Wet the joints before applying the mortar and be careful to keep it off the face of the stones or you could end up with stains which are hard to remove.
If the gaps between the stones are narrow, it’s easier to brush the mortar in completely dry, then set it with water sprinkled from a garden watering can.
CRACKS AND HOLES IN DRIVES
Cracks often appear on even the best laid drives, as continuous use, extremes of temperature and gradual subsidence take their toll.
Cracking is most likely to appear after a hard winter. Providing there are no signs of serious subsidence, you can patch the damage fairly simply.
1. Use a hammer and a bolster or cold chisel to enlarge the crack to about 12mm20mm wide and undercut the edges as much as possible to provide a grip for the new mortar filling. Clean out all the dust and loose debris before proceeding.
I 2. Ordinary repair mortar tur \ has difficulty adhering to drives. For extra grip, prime the crack with a solution of one part PVA adhesive to five parts water. Allow this to dry while you mix the mortar, then recoat the area with a stronger solution of three parts PVA to one of water. Apply the mortar while the adhesive is still tacky.
3. Use readymix repair mortar for this job, mixed in the ratio of one part cement to three of sand. Press the mixture well into the crack and level as it ‘goes off’. Holes: If holes appear in the concrete the most likely explanation is minor subsidence. The filling procedure is the same as for cracks but strengthen the drive’s hardcore base.
4. Hack the broken concrete out of the hole, break it into small pieces, then ram it well down into the hardcore.
To fill the hole, you’ll need to make up a proper concrete mix: use either cement, concreting sand and 20mm coarse aggregate mixed in the ratio 1:2 ½:4 or cement and allin ballast in the ratio 1:5. Clean the hole, prime it with adhesive, then fill it with concrete.
Compact the concrete using the edge of a board in a chop. Ping action. This will give a rough surface to match most drives.
5. If you want a smooth finish. Rub the wet concrete with a plastering trowel to bring the cement and sand to the surface.
Then ‘polish’ it with the trowel as it starts to set.
RENEWING A CRUMBLING CONCRETE EDGE
Concrete paths and drives are most vulnerable at the edges, particularly if they have not been strengthened with kerbstones.
The hardcore base and soil can get washed away during heavy rain, causing the unsupported edge to break up. 1. Cut back the crumbling concrete until you reach a sound edge. Put the concrete debris aside as you may need it later for hardcore.
Ram down the existing base hardcore as hard as you can, if necessary adding some of the concrete debris broken into small pieces.
Fit a length of 25mm thick timber against the original edge of the path and secure with pegs driven into the ground. Make sure the top of the board is level with the surface of the path and that it is supported at 600mm intervals.
Make up a concrete mix of one part cement to five parts allin ballast — or as you’re unlikely to need a great deal of concrete buy a readymixed bag.
Prime the edges of the sound concrete with a 1:5 solution of PVA adhesive and water. When it has dried, recoat with a stronger 1:3 solution and trowel
in the concrete mix while this is still tacky.
2. Use the edge of your trowel in a chopping motion to force the concrete under the edges of the patch. This will also compact the concrete and remove any air pockets in the repair.
Try to match the surface finish of the existing path as closely as you can. Chopping with the edge of a thin board will produce a rough surface like that found on most paths, but for a smoother finish you can draw a stiff brush lightly over the surface of the concrete when it has started to harden.
DEALING WITH DAMAGED ASPHALT
Asphalt drives are surprisingly durable, but if they sustain minor damage which is not repaired, frost or rainwater may get under the asphalt and quickly cause a small hole to become a large one.
1. Cut the edges of the damaged area back into a regular shape and trim them straight using a hammer and bolster — you must have a firm edge to butt the new macadam up to.
2. Before filling the hole, clean out the area affected and inspect the foundation. If the asphalt is laid over concrete, there should be no problems. But if it’s laid on hardcore, you must strengthen the hardcore base before relaying it.
Fill the hole with cold macadam, which you can buy in small bags from most builder’s merchants. Build it up just proud of the surface then roll it, preferably with a garden roller but otherwise with any roundsection wood, to compact it.
When repairing a large area, always roll the macadam from the outer edges inwards, otherwise it will stick like pastry. Avoid sticking by dampening the roller.
If the edge of the drive has crumbled, cut back to firm material and form a regular, straightsided hole.
Brush away the debris and flatten and level the base, then secure a piece of timber along the old edge with pegs. Tap it down level with the surface of the existing asphalt.
3. Spread cold macadam into the hole until it is proud of the surface, then roll it flat with a dampened garden roller.
4. If you don’t have one of these, for this job it might be worth making a compressing tool by nailing a 150mm X 150mm piece of blockboard to a broom handle.
Leave the edge board in position until the macadam sets hard and try not to use the drive for a further 24 hours after that.
LARGE SCALE REPAIRS
Severe cracking on a concrete path or drive may be due to one, or a combination of, two things: either it wasn’t laid properly in the first place or the ground below has suddenly subsided.
The only really satisfactory cure is to break up the whole of the affected area — back to a firm base — and lay fresh concrete, using the old debris as hardcore.
The best tool for concrete breaking is a heavy duty jack hammer.
You can hire these quite cheaply, along with a range of chisel shaped bits.
Be sure to protect your eyes and face when using the jack hammer.
Keep your protective clothing on when you smash up the concrete afterwards using a pick or sledge hammer.
If you find that the ground below the concrete is particularly light and sandy you would be well advised to reinforce the new concrete using wire mesh. Reinforcing mesh is available from builder’s merchants in rolls — ask for 100mm X100mm mesh with 6mm wire and buy enough to cover the weak area completely.
The new hardcore base must be firmly compacted and around 100mm 150mm thick; you can hire compacting machines to help with this part of the job.
The concrete that goes over the top should be 75mm100mm thick, with the reinforcing mesh set on rubble about 40mm above the hardcore.
If you can, order the concrete readymixed: specify the air entrained sort, which has a much better resistance to cracking when it has set.
Check that the hardcore base is more or less level with a spirit level on a long straightedge, then
lay out the mesh over the site.
Raise the mesh 40mm above the bed by supporting it on stones or pieces of brick.
Now erect shuttering around the site by setting wooden boards against pegs and adjusting their heights to match the depth of the concrete. Note that if they are too wide, you can recess them in channels dug in the ground.
When you pour the concrete, take care not to disturb the mesh and make sure that there are no air pockets left below it. Level off the new surface with the aid of a helper by running along it against the shuttering using a homemade timber tamping beam in a chopping motion.
When a large area of drive subsides, relay it using extra hardcore to bolster up the subsoil and to provide a firmer base.