Pergolas And Arches
Overhead shade and plant supports were always a part of the traditional garden. Timber was the usual material for pergola walkways, supported by either heavy brick piers or wooden posts. The same pleasures are sought today but metal is now the material most often used. The overall look of a pergola has otherwise changed little, however, being either simply rectangular or arched, althought the scale and proportion will be somewhat reduced in the modern versions. Today’s pergolas also tend to be less elaborate than previously, with fewer plants.
Some arches and pergolas are simple to install and economic, being made of lightweight aluminium, coated with plastic. These simple arched frames can be pushed into the soil and, provided lightweight plants are grown over them, they will withstand wind. The original single, wide iron hoops of the past enabled expansive arabesques of twining climbers to soar overhead; these suit contemporary formal styling just as well and may cross wide paths. Clematis are the ideal climbers for this situation: avoid planting in a frost pocket and ensure that the roots are shaded.
If you intend a pergola to carry heavier climbers, the posts must be strong enough and tall enough, preferably 2.5m (8ft), to allow weighty climbers like wistena or roses to trail clear of the head of a person below. If made of timber, the beams and rafters should be deep (150-200mm/6-8in) with an average thickness of 50mm (2in), to avoid warping. Bases should be firmly secured in concrete in the ground, against high winds.
For a modern house made of concrete, glass and steel, the architectural value of using heavier ‘construction’ steel beams (usually hidden inside concrete) for a pergola is that the garden will relate clearly to it. These structural beams tie house and garden together, defining line and indicating three-dimensional volume with great simplicity. Scaffolding will achieve the same purpose more economically, with a lighter intention.
A pergola is usually open on both sides but in some contemporary gardens it may be on the perimeter, so one side may be panelled to conceal an unattractive view. Along the boundary, mistily opaque etched glass or polycarbonate panels will allow light through or stainless steel must create ground-level shadow patterns along the length of the walk. Taut canvas may also be used stretched overhead for screening. In the absence of overhead cover, however, consider the dramatic foliage of large-leaved climbers like golden hop (Humulus lupulus ‘aureus’) or the massive-leaved Japanese glory vine (Vitis coignetiae).
Canopies And Awings
No garden should be uncomfortable and all that may be needed where people sit is a means of filtering the light. In hot areas canopies protect people from the sun while allowing some light through. Transucent or opaque fabric panels can be made from canvas, flame-resistant PVC-coated polyester, coated glass cloth or other materials that can withstand wind and weather and are not too costly. Flimsy, muslin-like fabric may be draped like blinds, strung over taut yachting wire or rolled back over a timber dowel to protect a seating area from the midday sun.
If a summer house is visible, the construction will dominate the view unless it is made from the same material as the house. Or it may be pale, if made from painted timber, or transparent if largely glass, both of which can be a foil for a more dramatic-looking feature or architectural plant in front. Freestanding summer houses are usually rectangular, hexagonal, square, octagonal or circular in shape; the basic geometry is best kept simple, with little adornment. You could have a custom-made summer house designed by an architect or craftsman, as a feature to suit the mood of the garden. Views out need to be considered when siting a summer house—you want to look at an attractive scene from you retreat. Another possibility is to put it on a turntable, to follow the warmth of the sun. The back can be used for the storage of garden implements and will do away with the need for a shed.
In practical terms all outdoor buildings should be waterproof and built on a solid foundation. The aspect is a major consideration; most summer houses are built in a sunny part of the garden to provide shade in the heat of summer. Ventilation is important as well, particularly if there is a lot of glass this could be provided by windows that open or screens that slide. In exposed areas the walls of the building must protect people from the prevailing wind. In hot conditions there will be a need for blinds both to cool and to shade the building; they could have timber or aluminium slats resembling the linear patterns of Venetian blinds. For a softer look, threaded reed matting, machined split-bamboo canes or stiffened cotton fabric are all effective. They can be controlled by winding or pulling, using rolling or concertina folding.
Traditionally, summer houses were made of hardwoods like western red cedar, Douglas fir, cedar or oak. Pressure-treated softwoods can be relatively durable, particularly if they are coated by protective paints or microporous timber stains formulated for external use. But the frame could equally be metal, steel or aluminium and the walls made of toughened, tinted, etched or transparent glass. New, ultraviolet-resistant plastics like polycarbonate sheeting also make translucent or opaque windows or walls. If these are hinged or removable, the building could have a completely open aspect in very hot weather.
For a contemporary look, the roof of a summer house may be clad with turf. These work best if pitched but are also effective when flat. In an austere, modern setting the look of a turf roof is surprising but very attractive. The existing roof needs a padded base over which you lay a waterpoof layer of tough plastic sheeting, followed by the planting medium which may include rockwool or a lightweight compost. Lay the turf and make provision for drip irrigation, concealing the tubes behind the building. A turf roof is extremely easy to maintain by removing invasive weeds once or twice a year and trimming the grass with shears. An incidental virtue is that the summer house will have both thermal and sound insulation.