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Conservatories - Frequently Asked Questions
- Q: What size conservatory do I need?
- Q: Where should I locate my conservatory?
- Q: Will my conservatory fit in the space available?
- Q: How can I get rid of my old conservatory?
- Q: What access is required to deliver my conservatory?
- Q: Is my conservatory suitable for DIY assembly?
- Q: Can I have electricity in my conservatory?
- Q: What is Reflex glass?
- Q: Is planning permission required for my conservatory?
- Q: Is building regulations approval required for my conservatory?
- Q: What is FENSA?
- Q: Will my conservatory require FENSA approval?
- Q: Will my conservatory need safety glazing?
- Q: Will my conservatory affect existing ventilation?
- Q: Will my conservatory affect an existing means of escape?
- Q: Will my conservatory affect existing disabled access?
- Q: Can I build my conservatory near a main sewer?
- Q: Can I build my PVCu conservatory near a gas flue?
- Q: How much heat will my PVCu conservatory lose?
- Q: How much heat and light will my PVCu conservatory transmit?
- Q: How much ventilation will my PVCu conservatory need?
- The space will always be used, so buy the biggest conservatory 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 conservatory is dictated by the space available. At Summer Garden Buildings we offer a wide range of sizes to suit every space. The rectangular shape of an Edwardian conservatory is more practical than a Victorian conservatory if space is limlited. If you are replacing an existing conservatory, you should consider whether to have the same size again or perhaps larger. You should also consider how many people you might like to seat in your conservatory. Also, could your conservatory be used for dining? The smallest size is generally 8'x8'. The most popular size for a small conservatory is 10' x 8'. A popular size for a large conservatory is 10' x 20' - large enough for dual use, with a lounge area and a dining area or perhaps a utility room and a lounge area.
- A south or west facing conservatory will require plenty of ventilation and reflective roof blinds. A north or east facing conservatory will require more heating. A south facing conservatory is warmest. A west facing conservatory is sunny in the evening. A north facing conservatory is the most sheltered. An east facing conservatory is sunny in the morning and makes a good breakfast room.
- When considering the position and size of your conservatory in relation to your existing property, the external base size and the external ridge height are often sufficient. However, in some situations additional details may be needed to ensure a neat fit. You should allow 2" or 50mm for external and internal cill overhangs and 4" or 100mm for the gutter overhang. A gutter downpipe requires a minimum clearance of 6" or 150mm outside the base. Dwarf walls are normally 10" or 250mm wide (100mm brick + 50mm cavity + 100mm brick). Dwarf walls are normally 14" or 350mm wide if you include the internal and external cill overhangs. A minimum 3" or 75mm flashing upstand is required above a pitched conservatory roof. A minimum 6" or 150mm flashing upstand is required above a low pitched lean-to conservatory roof. A minimum 12" or 300mm wide clearance is required between the base and any fence or wall and if possible 18" or 450mm clearance is preferable. All dimensions are approximate for guidance only and we recommend that you allow plenty of tolerance. Ideally your conservatory 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. If the space around your conservatory is restricted remember to allow for any roof overhang. You should also cut back or remove any nearby shrubs and trees. Remember to allow for future growth. If possible a sheltered position is better.
- The easiest way to remove your existing conservatory is to sell it. There's a very healthy trade in old second hand conservatories. Second hand aluminium conservatories are particularly popular as a bargain priced extra room. 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 conservatory 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 conservatory 8' x 12' double doors, roof blinds, good condition, buyer to dismantle, £300 for quick sale. Phone 01234 567890"
- Your conservatory will be delivered by prior appointment with you. A clear access route is required from the lorry to the storage area, with no access restrictions. The PVCu sections are often large flat panels. Possible restrictions include archways, narrow passages, sharp corners and flights of steps. It is not normally possible to lift large PVCu panels over fences and walls. Access through the house may be possible with advance notice. If required larger PVCu panels can be made in smaller sections for a small surcharge. Please advise us if there are any access restrictions at the site.
- Summer PVCu conservatories are designed for DIY assembly. Assembly is a satisfying project for any DIY enthusiast. Even large PVCu conservatories 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 PVCu 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.
- Although providing an electricity supply to a conservatory 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.
- Reflex glass is the next generation of conservatory roof glass designed specifically for the British weather. Reflex glass tackles the twin problems of overheating in summer and keeping warm in winter. Specify Reflex glass to give yourself a conservatory which is more comfortable throughout the year. This "smart glass" uses an invisible metallic coating which keeps out 75% of solar heat in the summer whilst providing 50% more insulation in the winter. A special coating is applied to the inside of the external pane of glass so it faces out towards the sun. The same technology is used to coat the surfaces of LCD and plasma televisions to reduce reflectance. The subtle blue tint reduces glare by up 44%. Harmful UV transmission is also reduced to approximately 5% eliminating damage to furniture and fabrics. During the summer a south facing conservatory can reach temperatures above 40 degrees Celsius which makes the conservatory unbearable. With Reflex glass the temperature inside the conservatory is reduced by 10 - 15 degrees. Reflex glass has a heat loss co-efficient or "U" value of just 1.4 W/m2K. This provides big savings on both winter heating and summer air conditioning when compared with standard double glazing units which have a "U" value of 2.8 W/m2K. Finally, an "easy clean" external surface treatment promotes dirt run off with rain, reducing the need for cleaning and keeping the glass looking fresh. Developed for marine applications this coating is ideal for conservatory roofs where access for cleaning is difficult. The hydrophobic polymer coating surface repels water taking dirt particles with it. This advanced non stick coating is permanently bonded to the glass and providing abrasive cleaners are not used the surface protection will last for the lifetime of the glass.
- Many conservatories do not require planning permission. However, permission is required for any conservatory which covers over half the garden, which is not for domestic use or which is over 4 metres high. Conservatories which are within 2 metres of a boundary with an eaves height of 3.0m or more (8'2") also require planning permission. Planning permission may also be required for any conservatory 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 conservatory. This brief summary is not intended to be a comprehensive guide. Contact us for further advice or contact your local planning department.
- The majority of conservatories do not require approval under the building regulations. However, approval is required for any conservatory with an internal floor area of more than 30 square metres. Approval is also required if there is no door between the conservatory and the dwelling. Approval is also required if a heating system is installed in your conservatory which does not include separate controls.
- Following a change to the building regulations, from July 1st 2002 all new and replacement window and door installations must comply with the requirements of the following Approved Documents:
What size conservatory do I need?
Where should I locate my conservatory?
Will my conservatory fit in the space available?
How can I get rid of my old conservatory?
What access is required to deliver my conservatory?
Is my conservatory suitable for DIY assembly?
Can I have electricity in my conservatory?
What is reflex glass?
Is planning permission required for my conservatory?
Is building regulations approval required for my conservatory?
What is FENSA?
- Approved Document L1 - Conservation of fuel and power
- Approved Document N - Glazing - Protection against impact
- Approved Document A - Structure
- Approved Document B - Means of escape in case of fire
- Approved Document F - Ventilation
- Approved Document M - Access and facilities for disabled people
FENSA registered companies are legally obliged to report every new or replacement window and door installation to FENSA who regularly inspect a random sample of installations either during or after installation. FENSA automatically issues a certificate of conformity direct to householders after completion of the work, regardless of whether the work is inspected. This certificate will be required during conveyancing to prove compliance with the regulations. Householders who cannot produce the certificate will face a reduction in the value of their property. The FENSA scheme covers the replacement of existing windows and doors in a domestic dwelling and also covers the enlargement of existing window and door openings if no new lintols are required (e.g. installing a new door in lieu of an existing window). The FENSA scheme does not cover the creation of a new doorway or window opening if a new lintol is required. This is a structural alteration which requires a separate application to the Local Authority Building Control Department. The replacement of garage doors does not require FENSA certification.
Will my conservatory require FENSA approval?In order to comply with Approved Document L1 (Conservation of fuel and power) all new or replacement PVCu and timber windows, doors and rooflights are required to achieve a specific U-value. In addition, all new or replacement installations must be adequately draught-proofed and reasonably airtight. FENSA inspectors will therefore inspect both the draught proofing of sashes and also the seals between the frames and the existing walls. A conservatory is not required to comply with Document L1 provided that it is separated from the dwelling by a door and provided that any fixed heating installation (e.g. a radiator) has separate temperature and on/off controls. If the proposed conservatory is not separated from the dwelling by a door (e.g if a clear walkthrough opening is to be created), a separate application to the Local Authority Building Control Department is required. Calculations of the U-value of the dwelling before and after the addition of the conservatory will be required and permission will only be granted if the U-value is improved by the addition of the conservatory, which is unlikely.
Will my conservatory need safety glazing?All glazing in conservatories must comply with the safety glazing requirements of Approved Document N (Glazing - Protection against impact). In order to comply with Document N any glazing within 800mm of the floor must be safety glazing (i.e. toughened or laminated glass). Any glazing in a door, a sidelight or a window adjacent to a door which is within 1500mm of the floor must be safety glazing (i.e. toughened or laminated glass). Doors with small panes of glass (e.g. georgian style doors) which are less than 250mm wide and less than 0.5 square metres in area can be glazed with 6mm thick float glass in lieu of safety glazing. Window handles must not be more than 1900mm above the floor, or 1700mm above the floor if there is an obstruction such as a kitchen unit.
Will my conservatory affect existing ventilation?All replacement doors and windows are required to provide sufficient ventilation to ensure that the room complies with the minimum ventilation requirements of Approved Document F (Ventilation). If a replacement door or window is enclosed within a conservatory and requires trickle ventilation in order to comply with Document F, the conservatory should have trickle ventilation of equivalent capacity. If a replacement door or window is enclosed within a conservatory, the conservatory requires opening doors and windows with a ventilation area equivalent to at least 1/20th of the combined floor area of the conservatory and the adjoining room or rooms.
Will my conservatory affect an existing means of escape?If a first floor bedroom window is replaced the new window must incorporate a side opening sash with fire egress hinges which open more than 90 degrees, even if the original window has no fire egress hinges, in order to comply with Approved Document B (Means of escape in case of fire). If a conservatory is to enclose the main door into a domestic dwelling (e.g. the front door), every habitable room in the dwelling requires a side hinged sash with fire egress hinges which open more than 90 degrees. Otherwise, a conservatory is not required to conform to Document B.
Will my conservatory affect disabled access?If a door is replaced access for disabled people must not be worse than it was before in order to comply with Approved Document M (Access and facilities for disabled people). A replacement door therefore requires a threshold height which is the same or less than the door which is being replaced (e.g. if a patio door is replaced with a PVCu hinged door a low threshold cill will normally be required). However, if a new door is installed in lieu of an existing window, access for disabled people is automatically improved and a low threshold cill is therefore not required. If a door with a ramp and wheelchair access is replaced, the replacement door will require a ramp and equivalent wheelchair access. If a conservatory encloses the main door into a domestic dwelling (e.g. the front door), the conservatory must provide equivalent access for disabled people. Otherwise, a conservatory is not required to conform to Document M.
Can I build my conservatory near a main sewer?A main sewer normally serves hundreds of homes unlike a private sewer which only serves a few homes. Normally under public roads main sewers are sometimes laid beneath domestic gardens. In such cases a restrictive covenant exists under which the Water Authority has a right of access for repair or renewal and the right to restrict development near the sewer. Homeowners are usually aware if such restrictions apply to their property. If the pipe is ever renewed a trench is excavated to the depth of the drain, wide enough to provide access for lorries and diggers to both sides of the pipe. Water Authority approval is therefore required for any extension or outbuilding within 3 metres of a main sewer. The Water Authority may agree to a Build Over Agreement, subject to payment by the homeowner of an administration charge and provided that the conservatory foundations are deeper than the invert level of the sewer. Main sewers are often very deep and a piled foundation may therefore be required.
Can I build my UPVC conservatory near a gas flue?In order to maintain an unrestricted air intake to gas flues, minimum clearances are required. Naturally balanced flues require a minimum 600mm clearance required between a UPVC conservatory and a flue and a minimum 75mm clearance required between a downpipe and a flue. Fan assisted flues require a minimum 300mm clearance required between a UPVC conservatory and a flue and a minimum 75mm clearance required between a downpipe and a flue. The above restrictions can only be disregarded with the approval of the manufacturer's Technical Department.
How much heat will my UPVC conservatory use?The figures listed below show the rate of heat loss for various materials used in conservatory construction. The measurement of heat loss is known as the insulation value or U value, which is measured in Watts per square metre per degree Centigrade or Kelvin (W/m2K). The lower the U value the better the insulation properties:
- 3.1 W/m2K = 10mm twin wall polycarbonate
- 2.4 W/m2K = 16mm triple ply polycarbonate
- 1.7 W/m2K = 25mm multi wall polycarbonate
- 5.7 W/m2K = 4mm thick single glazing
- 3.3 W/m2K = Single skin brick wall
- 2.2 W/m2K = Double skin solid brick wall
- 0.6 W/m2K = Double skin insulated cavity brick wall
- 5.2 W/m2K = Aluminium door and window frames
- 2.6 W/m2K = Thermally broken aluminium door and window frames
- 1.7 W/m2K = Hardwood door and window frames
- 2.0 W/m2K = UPVC door frames
- 2.0 W/m2K = UPVC window frames
- 3.2 W/m2K = 16mm thick (4+8+4) air filled double glazed sealed unit
- 2.9 W/m2K = 16mm thick (4+8+4) argon gas filled double glazed sealed unit
- 2.6 W/m2K = 16mm thick (4+8+4) air filled double glazed sealed unit with K glass
- 2.2 W/m2K = 16mm thick (4+8+4) argon gas filled double glazed sealed unit with K glass
- 2.7 W/m2K = 24mm thick (4+16+4) air filled double glazed sealed unit
- 2.5 W/m2K = 24mm thick (4+16+4) argon gas filled double glazed sealed unit
- 1.7 W/m2K = 24mm thick (4+16+4) air filled double glazed sealed unit with K glass
- 1.5 W/m2K = 24mm thick (4+16+4) argon gas filled double glazed sealed unit with K glass
How much heat and light will my UPVC conservatory transmit?The higher the light transmission the more daylight will enter the conservatory and adjoining rooms. The higher the heat transmission the hotter a conservatory will be in the summer. Light coloured flooring, frames and walls will provide additional reflected light and reduced heat build-up but glare will be increased.
- 16mm thick clear polycarbonate = 76% light transmission and 82% radiant solar heat transmission
- 16mm thick bronze tinted polycarbonate = 35% light transmission and 55% radiant solar heat transmission
- 16mm thick white tinted polycarbonate = 48% light transmission and 71% radiant solar heat transmission
- 25mm thick clear polycarbonate = 44% light transmission and 66% radiant solar heat transmission
- 25mm thick bronze tinted polycarbonate = 23% light transmission and 49% radiant solar heat transmission
- 25mm thick white tinted polycarbonate = 24% light transmission and 50% radiant solar heat transmission
- Clear or obscure glass sealed unit = 80% light transmission and 75% radiant solar heat transmission
- Clear or obscure K glass sealed unit = 75% light transmission and 72% radiant solar heat transmission
- Bronze tinted anti-sun glass sealed units = 55% light transmission and 59% radiant solar heat transmission
- Green tinted anti-sun glass sealed units = 70% light transmission and 58% radiant solar heat transmission
How much ventilation will my UPVC conservatory need?The Chartered Institution of Building Services Engineers (CIBSE) Guide Book includes approximate guidelines designed to limit the solar gain in a UPVC conservatory to less than 120 for most situations in summertime. In north facing UPVC conservatories opening windows and doors of not less than 15% of the floor area are recommended. In south facing UPVC conservatories roof blinds and opening windows and doors of not less than 25% of the floor area are recommended.
Summer Garden Buildings is a leading UK retailer of DIY conservatories established in 1981 with a retail display site in Norwich, Norfolk.