The stepping stone path was chosen as a starting point because it should present you with no problems, but for all other types of path you will have to consider the three basic problems of path design: foundations, edgings and drainage.
The foundation for a path is the layer or layers of material under the top surface. It has two purposes: first, to provide a thickness of cheaper inorganic base material so that the path, thus thickened, rests on undisturbedfree from ; and second, to provide, when necessary, a sub-stratum of material that can be easily raked to allow the finishing surface to be laid perfectly level.
You should begin to make your path by digging a trench to the width and desired alignment of the path and to a depth equal to the combined thickness of the foundation and finishing layers. This overall depth for the trench can only be determined by you. It depends on your soil and on how much of a perfectionist you wish to be. If you are working on land with a shallow topsoil that has not recently been disturbed, 13-15 cm (5-6”) should be adequate. If you are working over soil that has been deeply dug and is soft to the tread down to a depth of 15 cm (6”), then it may be necessary to go as deep as 23 cm (9”).
Foundations such as these, however, are not suitable for drives over which motor vehicles are to travel: here the absolute minimum depth is 23 cm (9”). For such vehicular drives the foundation has a third purpose: to spread the downward force of a ‘point load’ over a wider area of soil. When joining a drive to a public highway it is a legal requirement to consult the local planning authority.
In the case of a gravel path, the foundation can be merely a simple layer of base material, but for paths finished with paving stones, tiles or bricks, a second layer to the foundation is required in order to fill the gaps in the rough base material and provide a surface that can be worked level. Sand is the best for this, but ash from a fire or boiler may be used instead.
The edges of paths passing through a vegetable plot or area of fruit crops grown in bare soil need a reinforcement, which is unnecessary in a path bordered by grass. Obviously, if a gravel path is not edged in some way, the gravel path is not edged in some way, the gravel and the bordering soil will merge and the path will crumble away into an unweedable mess. If the path is of brick, the bricks at the edge will fall away when trodden on. Even with paving stones, there is the danger that digging alongside them will undermine the base, so that the edge stones are dislodged.
You will see suggestions for various edge details in our diagrams of paths. Even if you are interested in only one type of path, read the notes on the others, because several of the edge details are interchangeable. The illustrations also show edges with upstanding kerbs which, although often considered too harsh looking in the flower garden, have an advantage in the vegetables garden in that they prevent spillage of soil on to the path and simplify sweeping. On the other hand, they can be a nuisance when using wheelbarrows or other wheeled tools or machinery.
Drainage in relation to paths and terraces in the garden is concerned with the avoidance of puddles. To this end only truly porous types of path, such as the stepping-stone type and the broad-kerbed brick path, are laid truly flat. Try to lay out your paths so that there is always a slope towards the edges, allowing the water to be soaked up in the adjoining ground. A good basic rule is to try to achieve a slope of 1 in 40, either by means of a cross-fall (a slope)—as is best for paths of big paving stones—or by a camber (a slope to both sides)—which is well suited to gravel paths or those made of small units such as bricks. Only in very large paved terraces will gulley and drainage pipes be required to deal with surface water run-off.