Over 200,000 conservatories are built in the UK every year – that’s more than the number of new homes. And it’s not surprising. Of all the small construction projects you can undertake to expand living space, a conservatory is one of the cheapest.
Yet the British love affair with the ubiquitous glass and plastic garden room may be ending. Sales of uPVC for conservatories are shrinking, while the uptake for more inventive versions – from orangeries to designs incorporating the latest glazing technologies – has grown from a niche market to something approaching a movement. With a little research and careful planning, it’s possible to combine the money- saving elements of conservatories with the advantages offered by modern design and materials.
Style and design
The blueprint for British conservatories was drawn up by Victorian garden designer and architect Joseph Paxton, when he created the famous conservatories at Chatsworth, then the Crystal Palace itself. A century later, these huge iron and glass structures are still being replicated, in miniature uPVC form, across the country.
Sales of uPVC conservatories peaked in 2004/5, says Robert Palmer of Palmer Market Research, partly due to a slowdown in the housing market but also as a result of changing tastes. ‘The budget end of the market has seen the biggest drop in sales,’ says Palmer, ‘while the luxury and bespoke market is growing rapidly.’ Mock Victoriana is out: the new battleground in conservatory design lies between the traditionalists, pushing a return to orangeries, complete with solid columns, and the modernisers, utilising metal and wood to create striking forms to contrast with existing homes. ‘The key is now blending in,’ says Robin Parker of aluminium specialists Apropos. ‘Above all, our clients want conservatories to be integrated – not stuck-on glazed extensions.’
'Our customers, who have found their period homes to be too dark, are looking away from the traditional Victorian conservatory, but have not turned to modern glass structures. They want the solidity and shade that walls or columns can afford while letting in substantially more light than in the main body of the house'.
Mark and Amanda Briscoe had a £65,000 conservatory added to their arts and crafts home in Cheshire by Cowie & Roberts. The company carefully designed the addition to the old home, even down to the ﬁnials on the windows and the use of locally mined sandstone to match with original material. ‘We love the extension,’ says Amanda. ‘It’s our favourite room. My husband put in underﬂoor heating; I was cynical, but it’s really worked – we can use the space all through the winter, and the elevated position gives great views over the garden. Was it worth it? I took an intake of breath when we heard the cost, but we wouldn’t be without it now.’
Sam Ogilvie, who breaks the mould by designing modern contemporary designs using traditional timber materials, has seen a different approach from his clients at Bartholomew Conservatories. ‘We do a lot of work with listed buildings and it’s the contemporary designs that are looked on more favourably by borough councils. The Victorian pastiche is not really so popular any more. Our clients are attracted to our modern aesthetic, but they often opt for a safer version of our drawings – particularly when they think about re-sell potential.’
Rules and regs Generally, a conservatory will not need planning permission, provided it falls within your permitted development rights (check you haven’t used up your allocation) and ticks the boxes to be deﬁned as a conservatory. The checklist, which allows you to sidestep building regs under Schedule 2 (Exempt Buildings and Work), is as follows:
- The extension has a 75 per cent glazed roof; walls 50 per cent glazed
- Its ﬂoor must not exceed 30sqm
- It’s at ground level and separated from the house by walls, doors and windows of external quality
- It can be separated from the main house by the closing of doors
- It doesn’t have drainage facilities Any radiators/heating can be temperature controlled
- It complies with Part N (safety glass) and Part P (electrics) of the building regulations
- It must be single storey
If you wish to build outside these parameters, then building regs and planning will apply, and costs will rise. Remember: any new opening you wish to create between the addition and the main house will have to be approved.
A fairly straightforward system of concrete-ﬁlled trenches should be sufﬁcient foundations for any conservatory that does not need planning permission, normally between 65-100cm deep and 45cm wide [see conservatoryinfo.co.uk/ base_construction.html for details]. In some cases a more specialist system will be required, for example if there are lots of tree roots or the ground quality is particularly poor.
The thickness of the concrete plinth for the ﬂoor will vary depending on soil conditions, ﬂoor ﬁnish and whether underﬂoor heating is to be installed. If the land inclines signiﬁ cantly, a suspended ﬂoor with concrete piers can be the best solution. Many specialist companies will offer a complete service to carry out foundation building works as well as installation.
Double glazing has solved one of the key problems faced by large rooms of single glazing: condensation. In addition, low-emissivity, ‘low-E’, glass helps regulate temperature inside by allowing through short-wave radiation, like sunlight, but reﬂ ecting back long-wave radiation, such as heat from radiators, into your conservatory, making it easier to keep warm. Low-E glass has a greater resistance to condensation, and lower thermal conductivity, or U-value.
Current regs require a U-value of 1.8 for glazed units, which can be achieved by double glazing with an air gap of 20mm and one low-E pane – a more expensive form of glazing that, thanks to a conservatory’s exempt status, is not compulsory. There is no obligation even to make your conservatory double glazed, but people often choose to increase the speciﬁ cation beyond that required by regulations. ‘Awareness of what’s available is increasing,’ says Ogilvie. ‘Self-cleaning glass is very popular where access to roof glazing is an issue – often the case in urban projects.’ His most apparently over-the-top spec, though, was from a security- conscious client who requested bulletproof glass. ‘It turned out he needed it: he did get shot, but not in the conservatory we built for him!’
Heating and ventilation
Traditionally, conservatories overheat in the summer and are difﬁcult to keep warm in the winter. The best way to release heat from a glass box is by venting at the top, in the roof. Blinds are one common way of cutting down on overheating, although they can be unsightly. ‘I think it’s mad to spend a lot of time and energy getting a clean line and then destroy it with blinds,’ says Ogilvie. ‘We design every building with our heat speciﬁcation spot on, so we don’t need them.’ He points his unsure clients toward Saint Gobain’s Cool-Lite layer built into glass, which reduces solar gain by up to 70 per cent. ‘With modern products, a conservatory’s temperature can be pretty well regulated.’ The most efﬁcient way to heat your conservatory is to have a solid ﬂoor with underﬂoor heating – either an electric or hot water system – which has the advantage of absorbing solar radiation during the day, to re-emit it after dark.
Choice of materials
PVC is both good and bad: it’s cheap and easy to install, hard-wearing, but inﬂexible, non- recyclable and – many think – ugly. Aluminium, once prone to condensation, now comes with thermal breaks and can provide a sleek, contemporary proﬁle due to its relative strength. Apropos’ Parker says: ‘Aluminium is instantly modern. It can be powder coated, and has a very small proﬁle, leaving the glass to take centre stage. As soon as you start building a wood structure, your design errs towards being more traditional.’ Yet despite a certain prejudice, timber framing is becoming more popular. ‘It always adds a bit of warmth,’ says Ogilvie. ‘We only use hardwoods; oak has a terriﬁc look, and a contemporary oak structure can create linkage to an existing building. Our most popular hardwood is utile, reddish in colour and very stable, similar to orocco.’
For an ultra-modern, frameless look, direct bonded glass will give a superminimal ﬁnish. ‘It works well for panels,’ says Ogilvie, ‘but in my opinion can look odd as a whole room.’ Whatever style and design you go for, start planning now and your new addition could be up for when the sunshine arrives.