Principles of Paths and Driveways for the Garden

Drives

Gravel, when properly laid and maintained, is probably the most attractive material for drives, and it has the advantage of being inexpensive to lay and to maintain. It is important to stress that the gravel must be laid properly. The object is to achieve a firm surface that will not become a clayey quagmire in wet weather, that will not develop potholes, and that will not walk into the house when dry. The first essential is a good foundation. This should be made of a layer about six inches deep of builder’s rubble or ashes, well compacted. On normal soils this will provide all the drainage that is needed for a gravel drive, but on soggy soils 3-inch drainage pipes should be laid in a herring-bone pattern at a depth of 6 inches. When the gravel is laid it should be raked and rolled until a firm, even texture has been achieved. The main disadvantage of gravel is that weeds can grow in it, but this really is not a problem as they can easily be controlled by one of the persistent weedkillers.

Many people prefer drives with firmer surfaces, such as asphalt or tarmac mainly because they believe they are longer-lasting and need less maintenance. If this is to be so, they need to be laid as carefully as gravel. When tarmac or asphalt drives are laid over old gravel drives it is important that all loose chippings should be scraped off the surface of the old drive, that the surface should be re-levelled, and that persistent weeds should be killed before the new surface is laid. Both tarmac and asphalt should be laid at least one inch thick.

The main difference between tarmac and asphalt is that tarmac is laid cold and is porous, whereas asphalt is laid hot and is not porous. Weeds are more likely to come up through tarmac than asphalt. In either case it is important to see that the drive is properly levelled and cambered. Unless this is done puddles will form on asphalt drives, and frost will quickly break up the surface of tarmac drives. Gaps should be left in the edgings for water to drain away into lawns or borders.

Concrete drives are long-lasting, but many people find the glaring white of untreated concrete unattractive: in addition such drives are relatively expensive to lay. They should be placed on a solid foundation of hardcore, and the concrete should be laid 4 inches thick. A more attractive and economic proposition is to lay the concrete in two parallel strips for the wheels of the car to go along, and possibly to use some contrasting material for the strip in the middle and at each side. Grass is unsuitable for this strip, as oil drips would soon kill patches and make it unattractive, but pebbles or setts embedded in a weak mortar, loose granite chippings or larger chunks of random sandstone are all practicable and attractive alternatives. Another possibility is to lay a herring-bone pattern of bricks between the strips of concrete, and to use parallel rows of paving slabs instead of the concrete.

Paths

The basic principles of constructing garden paths are similar to those for drives, but scaled down. The layer of hard-core need not be so deep, and if concrete is used, it need be laid only 2 inches thick. It is seldom advisable to make a garden path less than three feet wide, and four feet is usually better if you can afford the space. This width allows for the passage of wheel-barrows, lawn-mowers and other garden implements, as well as for the temporary intrusion of pathside plants: it is always a shame to have to cut back one of these plants just as it is coming into flower, merely because it is obstructing a pathway. Except in very large gardens where special visual effects may be needed, there is seldom any point in constructing paths wider than four feet. In general paths should be level with the ground on either side of them, except of course, where they divide raised beds of a rockery from, for example, a lawn. They should also be flat rather than cambered, as this makes them more comfortable to walk along.

Where gravel is used a foundation of three to four inches is adequate on most soils, but on heavy land the foundation needs to be 6 inches deep, and on really badly drained land 3 inch drainage pipes should be laid in herring-bone pattern at 18 inch intervals. A layer of gravel 2 inches thick is sufficient. Concrete, when used for a garden path, looks utilitarian and it is usually preferable to try to find some alternative material. Bricks laid in herringbone pattern look particularly attractive, but the bricks must be sound or they will quickly be broken up by frost. There is a tendency for brick paths in shaded situations to become slippery: the slipperiness is caused by algae: it is a hazard that can easily be cured by watering with a proprietory algicide.

Other brick-like materials can also be used to make attractive garden paths. Stable-floor bricks, which have grooves in them for drainage, are attractive and can usually be bought inexpensively from demolition contractors, as can old limestone cobbles or granite setts, both of which make exceptionally attractive paths. When creating brick, cobble or granite sett paths it is best to lay a foundation of hardcore and then a 1 inch layer of concrete. Once this has been allowed to go off another 1 inch layer of weak mortar should be laid, and the bricks or setts embedded in this. Afterwards the bricks or setts can be pointed with a strong cement mixture, or earth can be used and grass allowed to grow up between the bricks. If this is the intention, extra care must be taken in getting the path level, otherwise it will be almost impossible to take the mower over it.

Paths do not necessarily need to be solid or continuous. Often ‘stepping stones’ in the lawn or through a rockery are just as serviceable. Paving slabs, which can be either of the old stone type or of the modern composition type, are the easiest materials for paths of this kind, but there are alternatives. If the stepping stones are required in the lawn, all that is necessary is to take out the turf to a sufficient depth, put in plywood shuttering, and lay the concrete in situ. Slabs made by this method can be rectangular, circular or irregular in shape. A similar type of stepping stone path can be laid between borders, simply placing the stepping stones on the bare earth. It is important that the ground should be thoroughly weeded and dug, and then allowed to settle before the path is laid. Random stone flags make the most attractive paths of this type. Once laid the earth between the flags can be kept clean of weeds by the use of foliar weedkillers, or creeping plants allowed to establish themselves between the flags.

Crazy paving is probably the most popular of all materials for paths. Again, either stone or composition paving can be used: both are long lasting, though stone is more expensive. To make a lasting path, crazy paving should be laid on a firm foundation of rubble and concrete, embedded in mortar and pointed with a strong cement. If spot plants are to be grown between the paving slabs, holes should be left in the concrete foundation for drainage.

Grass paths winding between borders or shrubberies can look good, but they will not stand really hard wear. The best grass paths are made from turves, but if seed is to be sown then a considerable proportion of Agrostis tenuis, an exceptionally hard-wearing grass, should be included.

Steps

Steps are needed wherever a path passes from one level to another, and frequently to provide a means of transition from one level of a garden to another. It is usual to construct the steps from the same material as that used for the path, and where the steps do not occur in a path the choice of materials remains much the same. The important thing about steps is that each step should be level: steps that slope away from you as you walk down them are lethal, particularly in wet weather. If they cover a large enough area to warrant a slope so that surface water will run off, the slope should be sideways, and a drop of half an inch in six feet is adequate.

Edgings

Formerly it used to be the fashion to use formal edgings to every path, border, lawn and drive in the garden. The main materials used were random stone slabs faced on one edge and inserted upright in the ground, brick, tiles or low box hedges. The fashion has now largely passed, and in general gardens have gained from its passing. There are still, however, places where edgings are desirable, as for example, to separate a border from a gravel path or drive. There are a number of possible materials that can be used. Concrete, though not the most attractive, is one of the most widely used. It is serviceable and long-lasting, though harsh to the eye in gardens that are in other ways mellow. Concrete edging can be bought in 4 or 5 foot pre-cast lengths, with rounded edges on the surface that will be above ground. These pre-cast lengths need to be set in a base of concrete. Far more attractive in most gardens is brick, but the bricks need to be sound and hard.

The bricks can either be laid horizontally as they are in walls, in which case they will need to be laid on a narrow foundation and cemented together with mortar, or they can be laid diagonally, or inserted vertically. Whichever style is adopted, trouble must be taken to ensure that, where they are to be laid in a straight line, that the line really is straight and preferably level. This is most easily done by using a line and spirit level and driving pegs into the ground beside the line of edging to the desired height. It is usually best to use mortar when laying a brick edging. If the bricks are simply set in the soil they are liable to move, and the line becomes untidy.

Tiles also make attractive edgings. These tiles are not of the type used on roofs, but of the type once fashionable in kitchen gardens. They come in a variety of colours and patterns, but are usually of unglazed dark grey brick, either crenellated or with a barley-sugar twist along the top. The easiest way of laying them is to take out a shallow trench, vertical on one side only, kept straight by means of a board, place the tiles in position and then lay a layer of concrete along the exposed side. Stone slabs, faced on one edge only, also make an attractive informal edging, and should be laid in a similar fashion.

Wood edgings are sometimes used: these may be either of wooden planks or more informally of lopped tree limbs. Neither is so harsh in appearance as some of the other types of edging, but neither is so long lasting. If planks are used they should be 6 in. x 1 in., and should be buried to half their depth in the soil and secured to stout pegs by means of galvanised nails. The pegs should be two feet long, inserted on the inside of the edgings at intervals of not more than six feet.

Patios

Patios are basically places for sitting out in the garden when the weather is fine, and as such are usually paved, either with crazy-paving or formal paving slabs, but there is a wealth of other materials that can be used to provide a variety of surfaces, colours and textures. From a design point of view a patio is a link between the house and the garden, and it should reflect the styles of both.

The method of laying a patio is basically the same as that for a paved drive or path. There must be a firm foundation, and a two-inch layer of concrete upon which the surface material will be placed. A patio should always be given a slope, so that water vvill drain away from the house, and a drop of 1 in 60 is sufficient to achieve this, provided that the surface material is laid relatively level. To achieve this drop the patio should be marked out with wooden pegs driven into the ground to the required depth.

Because patios are essentially sun-traps they provide an ideal place for growing tender plants that might not thrive in the open garden. This is particularly true of patios that are bounded by walls or fences, even if these are quite low walls and fences. Whether you intend to grow tender plants or not, you will want some colour in the patio, and so beds and borders should be planned before any concrete is laid: so should the position of any tree that is to be grown to cast shade. If the beds are situated at the foot of a wall they need to be at least eighteen inches wide, as walls tend to create rain shadows, ie. places shadowed from rain.

It is not necessary to build a patio on a rectangular plan, though patios are usually fairly formal places and lend themselves to this treatment. They can be any shape you wish, so long as they fulfil their basic function. They are often made more attractive if a number of differently coloured materials and different textures are used. Areas of sea-washed pebbles set in concrete relieve the monotony of crazy paving, and so do areas of brick laid level with the crazy paving. Garden pools, often with fountains, are frequently incorporated in patios, and the sound of falling water is certainly refreshing on really hot days. Statuary and urns and tubs of flowers all add to the gaiety of a patio.

 

 

06. September 2011 by Dave Pinkney
Categories: Gardening Ideas, Paving/Patios/Drives | Tags: , , , , , , | Comments Off on Principles of Paths and Driveways for the Garden

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