How many times
do we see advertisements which urge us to 'extend our homes tastefully and
economically' by buying some brand or other of conservatory? For many home
owners it clearly is an attractive proposition and if well designed, a light,
timber and glass structure may present the most sensitive means of extending
an historic house, allowing the original form of the building to be seen
clearly. However, a poor design can look ugly and out of place and whether
a conservatory might be an appropriate addition to an historic building
needs careful consideration.
The earliest known conservatories date from the 17th century. The first
in Britain is believed to have been constructed in the Oxford Botanic
Gardens, followed soon after by another example in the Chelsea Physic
Garden. In the 18th century, the orangery became a fashionable addition
to the English country house. At Kensington Palace in 1704 Queen Anne
commissioned a Baroque design, attributed to Hawksmoor for a free-standing
orangery in the grounds. However, it was not until the early 19th century
that conservatories came within the reach of private individuals. Glass
houses of all kinds became popular in the mid-19th century as improvements
in technology led to cheaper glass and cast iron and enabled larger sheets
of glass to be produced. Paxton's Crystal Palace, constructed for the
1851 Great Exhibition, provided a dramatic advertisement for glazed structures
and was a major influence on the popularity of conservatories. They reached
their zenith in the late Victorian and Edwardian era, but by the end of
the First World War they were no longer in fashion. In the last 30 years
there has been a resurgence in their popularity and hence the number of
firms producing a variety of proprietary and bespoke designs of differing
quality and cost.
When considering the introduction of a conservatory, location is obviously a fundamental issue. The most natural location would usually be at garden level to the rear of a property (the basement level in some cases). Victorian and Edwardian conservatories are sometimes found at the front of a house which is set in its own grounds, away from passing traffic, but hardly ever in front of a town house, and a new conservatory would normally look out of place in this location. In urban streets there may also be a problem locating a conservatory at the side of a property as the views between houses are almost always important to the character of the street. If placed on a roof or on top of an existing extension a conservatory can look completely bizarre, having lost its relationship to the garden. Where the prevalent pattern at the rear of Georgian and Victorian terraced houses is that of repeated light-wells and rear extensions (or 'closet wings'), it is most common to place the conservatory in the light-well between the extensions. Setting back the rear building line of the conservatory from that of the adjacent extension also helps to maintain the rhythm of original extensions and limits intrusion into the garden itself.
An important consideration is how the conservatory is linked to the parent building. Where a building is listed, protection includes the whole of the interior, not just the exterior, and the cellular nature of historic buildings is a key element of their character. The local authority's conservation officer is unlikely to allow a new conservatory to be merged with an existing room by the demolition of a whole wall as this would entail considerable removal of original fabric and alter the room's proportions and character. Much less intervention is necessary if an existing opening is used. Ideally this would be a door, but often it may be possible to drop the sill of an existing window opening to create a doorway. If the window is to be removed, consider reusing it elsewhere on the building rather than discarding original or historic fabric, particularly if other extensions and alterations are proposed at the same time. By minimising alterations in this way, the original building may continue to be 'read' through the conservatory.
The size of the proposed conservatory is also of crucial importance. At its most fundamental, all extensions must be clearly subordinate to the parent building if the character of the original architecture is to remain dominant, and should generally cover no more than half the width of the elevation.
When considering the footprint of a conservatory, the cellular structure of the house and the sense of hierarchy between front and rear rooms can be taken as a starting point. In most cases its floor area should be significantly less than that of the adjoining room to maintain the progression through the house from grand space to lesser spaces.
The plan-form should relate to that of the parent building and will often be dictated by the conservatory's location. Usually a square or oblong plan is adopted, but in some cases chamfering the corners may soften the appearance of a large structure and a polygonal form may relate better to existing features.
Two storey or double height conservatories are rarely appropriate additions to listed buildings as their overall scale can look out of place, and they may obscure relatively large areas of the elevation of the building. The same may be true of over-elaborate roof structures.
A glance at manufacturers' catalogues at the quality end of the market shows a preponderance of 'traditional designs' These are often based on Victorian and Edwardian styles and consequently may appear very ornate and fussy in appearance. On Georgian or early to mid-19th century houses these styles are likely to clash with the rather plain and restrained appearance of rear elevations. It is better to reflect existing character by simplifying the design. More elaborate designs are best suited to buildings of the Domestic Revival of the late 19th and early 20th centuries. Obviously a quite different approach needs to be taken with buildings of the Modern Movement and contemporary structural patterns and glazing might be utilised.
A potentially successful design may be let down by poor detailing. This may show on the solid lower sections of the conservatory where brick construction may give an unduly heavy or incongruous appearance. Timber panels are often crudely constructed with applied mouldings to imitate traditional panelling, and equal attention needs to be paid to the framing of the glazing which should be lightweight and delicately detailed. Double-glazed units with false glazing bars look false, particularly from the inside. Similarly, the appearance of the roof structure may be compromised by the use of wide aluminium cover-strips.
The colour for the joinery of the conservatory
may be chosen to match the existing woodwork of the house. However, as
this colour is usually white, one interesting alternative is to paint
the conservatory dark green to reduce its visual impact.
This article is reproduced from The Building Conservation Directory, 2000
DAVID MACDONALD is a member of the Institute of Historic Building Conservation and is responsible for conservation and design at the Royal Borough of Kensington and Chelsea. The views expressed are his own and do not necessarily represent those of the local authority.
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