Greenhouses - Frequently Asked Questions

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• Q: What size greenhouse do I need?
• Q: Where should I locate my greenhouse?
• Q: What type of base is suitable for my greenhouse?
• Q: How can I get rid of my old greenhouse?
• Q: What access is required to deliver my greenhouse?
• Q: Is my greenhouse suitable for DIY assembly?
• Q: Can I insulate my greenhouse?
• Q: Can I have electricity in my greenhouse?
• Q: Is planning permission required for my greenhouse?
• Q: Is building regulations approval required for my greenhouse?
• Q: What is western red cedar?
• Q: What is pressure treatment?
• Q: How should I maintain my wooden greenhouse?
• Q: Are cedar greenhouses better than aluminium?
• Q: Why should I choose an aluminium greenhouse?
• Q: Will my aluminium greenhouse last?
• Q: What is powder coated aluminium?
• Q: What are the benefits of powder coated aluminium?
• Q: How do I clean a powder coated greenhouse?
• Q: How do I clean my greenhouse glass?
• Q: How do I maintain my sliding doors?

What size greenhouse do I need?

• The space will always be used, so buy the biggest greenhouse you can afford provided that it fits comfortably in the space available. There are no precise guidelines regarding the size. Often the size of the greenhouse is dictated by the space available. At Summer Garden Buildings we offer a wide range of sizes to suit every space. If you are replacing an existing greenhouse, you should consider whether to have the same size again or perhaps larger. You should also consider what you will be growing. The most popular size for a small greenhouse is 6' x 8'. Sizes for the more dedicated gardeners range from 8' x 10' to 10' x 12' and larger.

Where should I locate my greenhouse?

• Ideally your greenhouse should have a clear space at least 18" wide on all sides, if possible. This ensures easy access for both installation and future maintenance. In reality this is often not practical and at many sites it is not needed. A reduced clearance is often possible on one or two sides. You should cut back or remove any nearby shrubs and trees. Remember to allow for future growth. Ideally the ridge of a freestanding greenhouse should run from east to west. A lean to greenhouse should be sited against a south facing wall. The best position for a freestanding greenhouse is a sunny spot outside the shadow of nearby buildings and trees. A sheltered position is best otherwise additional screening may be advisable. Plants need plenty of water so your greenhouse should be close to a water supply and the site should be well drained.

What type of base is suitable for my greenhouse?

• All greenhouses need a substantial base. The base should be solid, square, flat and level to ensure the stability of your greenhouse. Greenhouse bases can be laid on any hard flat surface including well compacted soil, paving slabs or concrete. However, a greenhouse without a base requires a brick or concrete plinth built to precisely the right size.

How can I get rid of my old greenhouse?

• The easiest way to remove your existing greenhouse is to sell it. There's a very healthy trade in old second hand greenhouses. You probably won't earn much money from the sale, but you'll get rid of it for nothing! The usual arrangement is to sell the old greenhouse for the buyer to dismantle at a time which is convenient for you. Ideally you should insist on full payment and immediate removal. If you settle for a deposit, perhaps with removal at a later date, make sure it's a significant deposit. You need to be confident that the buyer will return when agreed! You can normally place a classified advertisement in the local newspaper for a few pounds by phone or online, with payment by credit card. Typical draft advertisement: "Aluminium greenhouse 8' x 12' double doors, good condition, buyer to dismantle, £50 for quick sale. Phone 01234 567890"

What access is required to deliver my greenhouse?

• Your greenhouse will be delivered by prior appointment with you. Aluminium greenhouses are normally delivered in long boxes with the lengths of aluminium and smaller packs of the glazing. Access through the house may be possible if there is a straight route. Wooden greenhouses are often delivered in flat panels and a clear access route is required from the lorry to the storage area, with no access restrictions. Possible restrictions include archways, narrow passages, sharp corners and flights of steps. Access through the house may be possible if there is a straight route. Please advise us if there are any access restrictions at the site.

Is my greenhouse suitable for DIY assembly?

• Most of our greenhouses are suitable for DIY assembly. Assembly is a straightforward and satisfying project for any DIY enthusiast. Even large greenhousess can be installed with only basic tools, such as a hammer, a screwdriver, a power drill, a spirit level, an adjustable spanner, a knife, a stepladder and safety goggles. Particular care is required when handling glass and good quality gloves should be worn at all times. You should not attempt to lift heavy sections without a helping pair of hands. Remember that extra time spent preparing a good base is normally repaid with time saved later on during the installation.

Can I insulate my greenhouse?

• Greenhouses with polycarbonate glazing provide better insulation than greenhouses glazed with glass. Inexpensive bubble insulation can be easily fitted to the greenhouse frame. Heaters are also available. Selected greenhouses are available with internal partitions to provide for warm areas. Selected greenhouses are available with shading kits to protect plants from scorching.

Can I have electricity in my greenhouse?

• Although providing an electricity supply to a greenhouse is normally a straightforward task, for safety reasons we recommend that you consult an approved electrician first. Since January 1st 2005 all electrical work must be completed in accordance with IEE wiring regulations and BS 7671. Notifiable work must be either notified directly to the local building control department or completed by an operator who is approved under the Part P Electrical Competent Person Scheme.

Is planning permission required for my greenhouse?

• The majority of greenhouses do not require planning permission. However, permission is required for any greenhouse which covers over half the garden, which is not for domestic use or which is over 3 metres high with a pent roof or 4 metres high with an apex roof. Larger greenhouses which are within 2 metres of a boundary and over 2.5m high (8'2") require planning permission. Some larger greenhouses with apex or hipped roof designs may be over 2.5m high. Planning permission may also be required for any greenhouse which is nearer to a public highway than the original dwelling. For planning purposes a public highway includes any road or footpath with a public right of way. If you live in a Conservation Area or a Listed Building permission may be required for any greenhouse over 10 cubic metres. This brief summary is not intended to be a comprehensive guide. Contact us for further advice or contact your local planning department. Please note that planning regulations apply to any building whether temporary or permanent including greenhouses.

Is building regulations approval required for my greenhouse?

• The majority of greenhouses do not require approval under the building regulations. However, approval is required for any greenhouse with an internal floor area of more than 30 square metres. Please note that the building regulations apply to any building in excess of 30 square metres whether temporary or permanent including greenhouses.

What is western red cedar?

• Western Red Cedar is an attractive timber but it also has an unrivalled reputation for durability. It is ideal for use in the construction of wooden greenhouses and other garden buildings. The superior qualities of Western Red Cedar are summed up in this extract from the grading rules published by The Pacific Lumber Inspection Bureau:
• "The largest and finest of the cedars produced anywhere in the world, the Western red cedar is famed for its extraordinary durability and resistance to decay. Western red cedar is a distinct species, possessing all the desirable qualities of the other cedars, and additional advantages besides. It can be finished to a smooth, silky finish; it is free from pitch, it takes and holds stains and paints excellently, and has superior glueing properties. Its colour is extremely attractive, varying from almost pure white of the narrow sapwood to the light straw shade of dark reddish-brown of the heartwood. The wood of Western red cedar has a vey low coefficient of expansion, so that it does not shrink, swell or warp excessively, even when subjected to changing degrees of temperature and moisture. It has prime insulating qualities and its pleasing aromatic odour is repellent to moths, insects and vermin. The wood is saturated to every fibre with a natural preservative oil which renders it virtually immune to decay and gives it extreme durability without artificial preservative treatment. It is not necessary to paint cedar to preserve its surface, as it does not deteriorate appreciably even under severe climatic changes."

What is pressure treatment?

• Pressure treatment is a lifetime preservative treatment. We offer pressure treated wooden greenhouses. The preservative is forced into the timber under pressure and penetrates below the surface, whereas all other treatments apply a coat of stain to the surface of the timber only. Pressure treatment is almost colourless except for a slight green tint caused by the copper content in the preservative. No further treatment is ever needed but if you want a coloured finish you can paint over pressure treated timber with normal wood preservative in any colour.

How should I maintain my wooden greenhouse?

• Unless your wooden greenhouse is made from cedar it will require regular treatment. Summer Garden Buildings recommends that the external timber should be treated with a good quality wood stain every year. This will prolong the life of your greenhouse. All major wood stain manufacturers offer suitable products in a choice of colours, available from good hardware shops. It is not necessary to treat cedar which is a naturally resilient timber and does not deteriorate appreciably even under severe climatic changes. If untreated cedar will gradually fade to a silvery grey. It is not necessary to treat pressure treated timber. If untreated pressure treated timber will gradually fade to a silvery grey. Summer Garden Buildings also recommends that you regularly oil the door and window hinges as required to ensure continued smooth operation.

Are cedar greenhouses better than aluminium?

• In scientific tests the performance of a cedar greenhouse was compared with an aluminium greenhouse of the same shape and size. The tests confirmed that cedar is the best material. Not only did the cedar greenhouse produce healthier and larger crops, it also used less electricity and less water. The tests included specific heat experiments. There were tests on frost sensitive plants such as french beans and tomatoes over a 3 month period in which both greenhouses were unheated. In another test both greenhouses were heated to a constant 65 degrees Fahrenheit using thermostat controlled blower heaters with electric meters across the power source to measure consumption. A series of plants were grown and at the end of the experiment a detailed analysis was available for both greenhouses together with electricity consumption figures. Crops were grown and detailed records were kept of all plants in the greenhouses which were treated identically in terms of heating, water and ventilation. The cedar greenhouse was shown to use 20% less electricity for heating purposes than aluminium. Comparing the crop from the tomato plants in both greenhouses the cedar greenhouse produced a higher yield by over 10%. More water was required in the aluminium greenhouse, mainly due to radiated heat from the metal drying the plants and soil rapidly. Moisture deficiency produces leaf curl which was more apparent in the aluminium greenhouse. The plants produced in the cedar greenhouse were on average 9 inches taller, largely due to the moisture level reducing more rapidly in the aluminium greenhouse. The temperature fluctuated less during the day in the cedar greenhouse. On sunny mornings at 8.30am the temperature was 6 degrees Fahrenheit when it was minus 2 degrees in the aluminium greenhouse. On colder mornings without sun the aluminium greenhouse was 7 degrees lower.

Why should I choose an aluminium greenhouse?

• Aluminium is an excellent material for greenhouse frames for many reasons. It is strong and at the same time very light with a higher strength to weight ratio than any other commonly used greenhouse framing material. In addition, aluminium needs no protective coating and it can be used in its natural state. Aluminium won't warp, rot or rust and it is non toxic.

Will my aluminium greenhouse last?

• One of aluminium's greatest attributes is its natural ability to withstand corrosion. An excellent example of its durability is the roof of the San Gioacchino church in Rome, which is roofed in aluminium and it is still in great condition after 100 years. Even after a hundred years of exposure the worst that happens is the surface takes on a rough grey texture as it very gradually oxidises. An unpainted aluminium greenhouse will gradually oxidise producing fine grey powder forms on the surface of the greenhouse. This is the aluminium's natural self protection and it does not harm the greenhouse. Oxidisation occurs quicker in areas of high pollution or in coastal areas.

What is powder coated aluminium?

• Powder coating is the application of paint in a dry form by the electrostatic spraying of charged particles of powder. Polyester powders have excellent weathering properties and retain their gloss and colour superbly. A good example of the finish achieved with powder coating is the finish on your washing machine, which is very similar to our powder coated greenhouses. The first powder coating systems for aluminium were developed in the 1950s. The aluminium was heated up and then submerged in tubs of powder. In the early 1960s this primitive system was improved with the introduction of curing ovens. The early powders were made from an epoxy based substance but this was replaced in the 1970s by the more durable polyester powders in use today. The powders are a blend of colour pigments and protective resin with hardeners and additives to improve spraying and surface hardness. The aluminium extrusions go through an extensive cleaning, etching and treatment process. This process removes impurities and swarf and smut left over after cutting. A final treatment allows the aluminium to take the powder. The extrusions are then dried. The aluminium is earthed inside the spray booth and electrically charged particles of powder are then sprayed onto the surfaces. As the aluminium is earthed and the powder positively charged the two are electrostatically attracted. The aluminium extrusions are then cured in an oven at 200 degrees Centigrade for ten minutes.

What are the benefits of powder coated aluminium?

• A powder coated aluminium greenhouse has a decorative finish but it is also protected against the elements. A powder coated surface is tougher than a wet paint finish and prevents unsightly surface oxidisation. The polyester powders have high colour and gloss retention. The popular green finish blends in with natural garden surroundings

How do I clean a powder coated greenhouse?

• In order to maintain the high quality finish a powder coated greenhouse can be cleaned regularly. The frequency of cleaning depends on the environment. If the greenhouse is in normal urban use a maximum interval of 18 months is recommended. In coastal areas or areas of pollution a greenhouse should be cleaned more frequently. The outside of the greenhouse can be cleaned using a mild detergent in warm water. All surfaces should be cleaned using a soft cloth, a sponge or a natural bristle brush. Cleaning the inside of the greenhouse can only be done outside the main growing season, probably in late September or October. For the plants sake use a mild disinfectant cleaning fluid as this will kill off any pests which could harm the plants.

How do I clean my greenhouse glass?

• The outside of the greenhouse glass can be cleaned using a mild detergent in warm water. All surfaces should be cleaned using a soft cloth, a sponge or a natural bristle brush. Cleaning the inside of the greenhouse can only be done outside the main growing season, probably in late September or October. For the plants sake use a mild disinfectant cleaning fluid as this will kill off any pests which could harm the plants.

How do I maintain my sliding doors?

• Sliding greenhouse doors normally have a nylon glide which runs in a channel which often gets blocked with grit and dirt. This will cause the doors to stick and wears out the nylon. The glides should be cleaned regularly to stop this happening.

View our Greenhouse Buyer's Guide.

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