Design & Technical

Guidelines

Planning Approval

Conservatories are generally constructed under ‘Permitted Development’. Permitted Development is a status that is assigned to a property at the time of construction. In some cases, most especially in the new high density build areas, this status is removed from the building which then requires approval by the Local Authority for any extensions to that building. To determine the status of the ‘Permitted Development’ associated with your property you should consult your Local Authority. Where ‘Permitted Development’ does apply to your property the amount of development is determined by the type of building, i.e., terraced, semi-detached or detached building. The base calculation is 50m³ for terraced properties rising to a maximum of 105m³ for a detached residence. In all case a height restriction of 4mtrs is applied. The ‘Permitted Development’ associated with your building may also vary dependant on the area in which it is sited. For example in a ‘conservation area’ the ‘Permitted Development’ amount may be reduced from 70m³ to 50m³, these variations can also be regional and are determined by your own Local Authority.

Where ‘Permitted Development’ does not exist a planning application to the Local Authority will be required to obtain approval prior to construction.

In the event that you property has already been extended, the volume of the extension has to be calculated and then added to the proposed conservatory volume to determine as to whether the combined developments exceed the ‘Permitted Development’ of your property. In the event it does a planning application will need to be made to the Local Authority for their approval.

Other factors such as the area status in which the property is sited, i.e. An Area Of Outstanding Natural Beauty, will also require a planning application to the Local Authority for approval prior to construction, as will the position of the conservatory in regard to the closeness of a highway. If a road is within 20mtrs of the new building, planning approval for the structure will be needed.

In any event it is wise to contact your Local Authority to check with the Planning department who will readily help with the clarification.

Building Control

In general terms conservatories are exempt from Building Regulations unless, the base area exceeds 30m² or a permanent opening exists between the main building and the conservatory. In these situations Building Control approval is required through the Local Authority. Some Local Authorities will allow the conservatory to be constructed under a ‘Building Notice’ which means that stages of the construction are inspected by a Building Control Officer. These stages cover items such as; the foundations; base construction – solid concrete, suspended floor; walls; frameworks; glazing and roofing. Supporting documentation such as structural calculations will be required to prove the integrity of the building and its compliance with the prevailing Building Regulations. Likewise, where a permanent opening is between the conservatory and the main building, heat-loss calculations will be required in the form of a SAPS report.

The other method to obtaining Building Regulations approval is by way of submitting detailed design drawings and calculations prior to construction. The benefit here is that when building the structure all construction issues have been addressed and agreed before the work starts.

In most events it is wise to contact the Local Authorities Building Control Department to clarify your own specific projects requirements.