Garden and Patio Boundaries
Walls and fences do more than just act as boundaries around a: they give shelter against prevailing winds for both people and plants, and confer a feeling of privacy; they are also useful for screening things like dustbins and sheds. Something is often needed, too, to make a natural break between paving and grass. Although can look very attractive, they take up a great deal of room, and rob the soil of nutrients for a foot or more on either side. They also need constant maintenance if they are to look trim. All things considered, a man-made barrier is usually the best solution. Solid screens made from brick or close-boarded wood are expensive but will last a long time. If you are planning a brick wall you need to dig a trench for the foundation; in the case of a fence, the posts need to be set in a concrete base.
Although a solid fence gives maximum privacy it can create considerable air turbulence on either side of it on a windy day. A more ‘porous’ structure may be kinder to your plants and make the patio more comfortable to sit in.
This is expensive but, once in place, will last a life-time. If you want to build your own, a low wall is certainly within the scope of the beginner. For best appearance use facing bricks, not ‘commons’. Even a low wall needs a concrete foundation. As a general guide a 375mm (15in) wide strip should be excavated for a wall up to 600mm (2ft) high. Dug until firm ground is found: if stability is in doubt, lay a bed of well-compacted hardcore. Allow for a 35mm (3in) layer of concrete (1 part cement to 2-½ parts sharp sand, 4 parts aggregate) with the first course of bricks to be below ground level. If the wall is to be more than 1.2m (4ft) high, lay a 100mm (4in) layer of concrete, with the first two courses of bricks below ground level. Mark out the line of the wall with two string lines pulled taut and tied to. Use a mortar mix of 1 part of cement to 5 parts of builders’ sand. The mortar should be buttery (not too dry, nor too wet). A few drops of washing-up liquid will improve its workability, but do not mix up more mortar than you can use in an hour.
This can look very attractive around a patio. It is made of precast concrete blocks, usually 300mm (1ft) square and 100mm (4in) thick. You need to provide a firm concrete foundation, using a mixture of 1 part cement to 5 parts 20mm (3/4in) ballast. For the mortar use 1 part cement to 6 parts sand plus plasticizer. The foundation should be a minimum of 200mm (8in) deep, including bricks or rubble where needed. At each end of the wall, pilaster blocks are used. Loose-lay the screen blocks between the pilasters to ensure they fit, then lay the blocks as for brickwork except that you should work from both ends to the middle. Check each block for level, and again build up the corners before completing successive courses.
Imitation stone blocks for walling can be used to achieve the formality of a traditional dry-stone wall. The blocks should be laid on firm foundations. Use a mortar mix of 1 part of cement to 4 parts soft sand. Joints should be about 6mm (1/4in) thick. If the wall is to be higher than four courses, allow a period of at least 48 hours for the mortar to harden before you begin laying the fifth and subsequent courses.
If all you need is a low, decorative retaining edge to the patio, it’s a good idea to build a wall made up of two parallel courses with a 150-200mm (6-8in) gap between them. You can fill the gap with soil and grow decorative plants in it. Even simpler would be a little, low wall made up of peak blocks which were interplanted with alpines and crevice plants so as to create literally a wall of flowers.
Like any other wall, it must be built on concrete foundations. Fill the bottom of the gap between the courses with rubble or hardcore.
If you want a solid wooden fence you have a choice between closeboard or interwoven ver-sions, both of which come as made-up panels usually 1.8m (6ft) wide and in various heights. Closeboard fencing is considerably dearer, and is often made of hard rather than soft wood. Both kinds need to be supported by posts fixed in concrete on a firm base; alternatively, you can buy special metal holders into which the posts are slotted and which spike into the ground.
If you merely want a rudimentary screen, there is a choice of wattle fencing, trellis, or chain link, or a decorative picket fence (planks of wood spaced several inches apart fixed on rails at the top and bottom). The lighter the fencing, the more important is it to make it totally secure; chain link and trellis both need some sort of frame around them if they are to stay taut. The advantage of openwork fencing is that you can decorate it quickly with climbing plants.