Concrete, Tarmac and asphalt are the hardest wearing surfaces for footpaths, and may be needed on heavily used urban paths, some paths in country parks and other recreation areas, and riverside paths. Tarmac and asphalt are not materials which are likely to be used by volunteer groups, so their use is not explained here. Concrete is an easier material to use than Tarmac or asphalt, and its colour is usually more sympathetic to a rural situation. Sections of path which cannot be drained or which are subject to stream or river erosion can be concreted. See Appendix D for suitable mixes.
Formwork paths
This is the standard method of making concrete paths, and results in a hard-wearing but rather unattractive path with straight edges. It will mellow with time if the edges are allowed to grow over. Always sink the path so the top of the concrete is level with the ground surface.
- Remove soil from the line of the path, allowing at least 75mm extra on either side for the formwork. Firm ground can be rolled and then the concrete laid direct.
Soft ground must be excavated further to give sufficient depth for a 75mm sub-base of hard-core or stone, topped with a 50mm layer of sharp sand. The concrete should be at least 75mm thick.
- Make the formwork of old timber, 25mm x 75mm. Hammer in pegs at 1m intervals and at joins in the formwork. Allow a cross-fall of 1 in 60 across the path by setting the formwork lower on one side (25mm on a path 1.5m wide).
- Put in an expansion joint every 3m, using a piece of wood. The wood can either be left permanently in place, or can be replaced by a piece of bitumen felt as the concrete is laid, and the wood moved on to make the next expansion joint.
- Pour the concrete from the barrow into the formwork, and spread evenly using rakes and shovels to about 25mm above the top of the formwork to allow for compaction.
- Fill to the next expansion joint, and then tamp using a tamping beam. Move the beam forward about half its thickness each time it is dropped. Tamp from one end to the other and then repeat once.
- An exposed aggregate finish gives a rough, non-slip surface. Brush with a soft broom one hour after laying. When the concrete has hardened enough for stones not to be dislodged, brush with a stiff broom to expose the aggregate. After brushing, cover the concrete with wet sacking and leave for several days. Water the sacking if the weather is dry.
Concrete ramps
These can be made in the way described above, on slopes of up to 1 in 5. It is technically possible to build long sections in this way, but does not make a very comfortable path to walk on. Sections over 5m long and 1 in 7 or steeper are better built as steps. Special provision should be made for disabled access. For details see ‘Informal Countryside Recreation for Disabled People’ (Countryside Commission, 1994).
Roughly fill the formwork to about 25mm below the top and allow to set for a few hours. Then working from the bottom upwards, fill to the finished level. As you proceed the bottom part begins to set and prevents the surface from slumping.
Concrete sandbags
This is a simple method for short sections of paths through damp ground which cannot easily be drained. Fill the sandbags with aggregate and cement in the proportion of about 4:1, and lay them dry on the surface of the path. Tamp down each sandbag with a punner, and don’t tread on the bags while they are setting. No drains should be necessary.
The sandbags will set to form a solid causeway, with the humped surface making it fairly unobtrusive, and giving some grip even when wet. A wider path could be made by laying two rows of sandbags. Do not stagger the rows, as the channel allows water to drain off the path.
