Building a ‘ceiling’ for the landscape

Press, 27 November 1979, Page 13

Building a ‘ceiling’ for the landscape

I 4 ' •The ceiling in the landscape can be of three b*sic elements — the ever-changing patterns and colours of the sky; the friendly, spreading canopy of large trees; and manbuilt structures. Overhead structur.es are important for those areas designed as an extension of indoor activities — for example, dining, entertaining. sitting, relaxing, reading, etc. Depending on the type of overhead space frame ujed. and its extent, there will be a definite psychological impact upon thj person underneath. A space frame can provide a sense of protection, security and comfort, similar to that of the house interior but without being so restrictive. Incorporating overhead structures into your design is one means by which a connection can be made between the house »nd surrounding landscape. Normally an overhead space frame of the architectural t'pe would be an open grid of beams and crpss-beams, perhaps partly covered by protective lithe work, canvas, vines, or similar. However. the space frame can also be covered by a solid type of material such as plastic sheeting. the decision whether to have a partial or full space-frame enclosure will

be determined by certain design factors — the degree of protection needed from sun, wind or rain, and the amount or density of shading required at a given time of the year. A space-frame structure can be attached direct to the house or it can be free-standing. In both instances it will assume visual importance due to its architectural form, colour and texture. The design of the space frame must be related to the architectural style of the house; and similar building materials should be used in order to tie the two firmly together. Generally the space frame will be above eye level, although not always, and the c , er-all design should take this point into consideration. A design which is too fussy or ornate should be avoided as normally the space frame is best sensed rather than seen. You don’t normally walk about looking upwards into the sky because it is not comfortable. If and when you do, it would only be very breifly, so keep the design simole and “clean cut”. Before undertaking the construction have plans prepared and discuss them with the building inspector to ensure that what you propose complies with local authority requirements.

You may well find that there are restrictions, so check this aspect before proceeding too far. The supports for a space frame may be of metal, timber, brick, or concrete block. The choice really depends on what the house materials consist of and the extent of the overhead framework. For an overhead structure timber is normally used, although metal may be used along with rope or wire. If the timber is Pinus radiata ensure it is ground treated (C 3 when in contact with the ground and that it has a C 6 treatment for above ground. In order to avoid a heavy appearance when using timber beams overhead. use 150 mm x 50mm, 200 mm x 50mm or 250 mm x 50mm sizes on edge. These sizes are more than adequate for a person to sense the space restriction and overhead cover. Any crossbeams used can be much lighter and would normally be placed at right angles to the main beams. The cross beams should be so placed as to allow light to filter down to the ground below. Coverings can be the summer coolness of a rambling vine or architectural materials such as canvas, plastic sheeting, woven plastic cloths, wire gauze, or mesh, bamboo blinds, decking — these

are some of the possibilities. It is possible for some of these covers to be made to roll back or to be lifted off when more sun is required during the Christchurch winters. Deciduous vines will have a similar result although there may well be some pruning and clean-ing-up work required. A point worth remembering with vines on a space-frame is that the frame should be high enough to allow a ground clearance of at least 2m below the hang of the vines. A person underneath will need this sort of clearance in order to walk around without hitting objects overhead. The space-frame is an important part of landscape design and could perhaps be used more than it is. Providing, as it does, shelter from wind and sun, it adds the third dimension to an outdoor space (the ceiling); interesting shadow patterns are created on the ground beldw; and the space, frame can be used to act as a transition between the building and the landscape.