The two questions you need to ask yourself are:

(1) Do I need planning permission?
(2) Do I need Building Regulation approval?

To help you understand these issues we detail below some of the "conditions" attached to planning permission and building regulations. (These apply to England/Wales only) Scottish, Northern Ireland, and Eire - You should in all instances take local advice.

PLANNING PERMISSION

In England and Wales you will not usually require planning permission, provided you do not exceed the permitted development limit for your property (which is 50-70 cubic metres, depending on where you live - a terraced house is normally 50 cuMtrs - detached and semi-detached 70 cuMtrs).
Notable exceptions to the above are listed buildings and conservation areas. Please note that if your property has been extended in the past - you will have used up some or perhaps all of your "permitted development" area and may need permission. Its also worth noting that occasionally "permitted development" rights may be withdrawn from a property and any extension however small needs planning. If in doubt check.

BUILDING REGULATIONS

Generally speaking conservatories/sunrooms on residential property are exempted under Building Regulations.

Below are some of the Exemption Criteria - under the Building Regulations 1991 (as amended). These criteria must be met for a conservatory extension to be classified as exempt:

a) The extension has a completely transparent or translucent roof.
b) The extension walls are substantially glazed. Must have at least half the area of the walls formed of windows. Must have at least three quarters of the area of the roof formed of glazing, polycarbonate sheets or similar translucent material.
c) The extension has a floor area not exceeding 30m squared.
d) The extension is sited at ground level.
e) The extension is permanently separated from the remainder of the property by means of a door.
f) Any radiator within the conservatory is controllable. (If fixed heating installations are proposed, they should have their own separate temperature and on/off controls).
g) The glazing satisfies the requirements of part N, Schedule 1 (toughened/safety glass).
h) The extension does not contain any drainage facilities. (i.e. sink, WC, or washing machine)

An example of where building regulation approval may be required is a Kitchen / Conservatory Extension. We suggest you contact your local council - explain your intentions - they will be able to give you more specific advice.

As a further guide conservatories that do require building regulations approval will need glazing of the highest insulation quality i.e. - Pilkington K Glass (low E) with argon filled units.

Providing all of the above can be met then an application, under Building Regulations, to build the conservatory is currently not required and neither will the building control department of your local council need to inspect it.

Please note – building regulations is a separate issue from Planning Permission. You should always check to see if planning permission is also required before going ahead and building a conservatory. More Details may be found here: http://www.planningportal.gov.uk/

It should be noted that there has been discussion about making all conservatories subject to building regulations and it could be that in the next 2 – 3 years ALL conservatories will be subject to building regulations.

If Building Regulation consent is required, what regulations apply?

Energy Conservation

The most common situation where Building Regulation consent is required is shown in Diagram 2 above. With a layout such as this, the “conservatory” is not separated from the house and under the regulations has to be considered as an Extension. Clearly, heat and energy will be more rapidly lost from the building with this arrangement. Because the UK Government is committed to reducing energy consumption and carbon emissions at UK power stations, Building Regulations now place limits on the amount and type of glazing in extensions (and also new buildings).

To meet the Regulations in this case, there is a choice:

1) To provide your local building control department with calculations that show the amount of glazing in the windows, doors and roof of the conservatory/extension, together with the amount of glazing in the windows, doors and any roof lights in the original house, do not exceed 25% of the floor area of the conservatory and all floors of the house added together. The new windows and doors in the Conservatory/extension will need to meet the current U values. Examples of types of glazing which will meet this are given in Table 1 below.
2) To provide Building Control with calculations or plans that show the amount of glazing in the windows, doors and roof of the ‘conservatory’/extension do not exceed 25% of the floor area of the ‘conservatory’/extension. Often, this can be difficult to achieve. The new windows and doors in the ‘conservatory’/ extension will need to meet the current U values. Examples of types of glazing which will meet this are given in Table 1 below.

Table 1

Material of the frame to the Window, door or roof light U Value required Example which meets Regulations
Wood 2.0 e.g. Double glazing with low E glass and 12mm air gap
PVC-u 2.0 e.g. Double glazing with low E glass, Argon gas fill and 16mm air gap
Metal (e.g. aluminium, steel) 2.2 e.g. Triple glazing with low E glass and 12mm air gap

Structural Alterations

Whether or not the conservatory is exempt, Building Regulation approval will always be required where it is necessary to form a new or wider opening in the original house wall, (see Diagram 2). This is because carrying out this type of work is a structural alteration and your local building control department need to check that the beam or lintel that is used to support the wall above the opening is of adequate size and properly fire protected.

Safety Glazing

Whether or not the conservatory is exempt, glazing in some of the windows and doors will need to be either toughened or laminated safety glass to meet British Standard 6206. Generally, the locations, which need safety glass, are doors and side panels and also where the glass in windows is within 800mm of floor level. For more information on safety glass see: http://www.double-glazing-uk.co.uk/Safety_glass.asp

Other Regulations

Where a “Conservatory” is treated as an extension, as well as energy conservation, there are additional regulations, which will also apply. These include:

1) Foundation design. (Raft foundations may not be suitable – check with your local building control department)
2) Fire spread across the boundary. (Large amounts of glazing are not permitted on or close to the boundary – check with your local building control department.
3) Preventing damp. (Cavity walls with damp proof courses and floors with damp proof membranes)
4) Drainage (Surface water from gutters and down pipes will need to discharge to a proper drain and not simply into a rainwater butt)
5) Ventilation of adjacent rooms. (Diagram 2 shows the Dining Room window enclosed but in order to comply with building regulations we believe that the dining room and living room would need to be made into one room (open plan) with ventilation then being provided by the Living Room window)

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