Building Regulations

Building Regulations - A Brief Explanation

From April 1st 2002, it became mandatory for all replacement windows and some door installations to be regulated by building control regulations. The regulations cover many aspects of the installation to ultimately offer minimum levels of product quality and installation competence including the products’ thermal performance and areas such as high risk glazing areas, overall safety, air flow, means of escape and minimum requirements of ventilation. Each aspect controlled by Building Regulations is covered by their relevant legislation publication, known as “Approved Documents.”

These Approved documents are available to download for further reading.


You should always ensure whichever company or contractor you employ to carry out any work in your property is fully registered with one of a number of relevant competent persons’ scheme. An approved installer will be able to self-certify and through the process of rigorous application and approval, will have shown to be able to demonstrate a minimum level of competence to carry out the work to comply with building regulations without the necessity to involve any local authority building control, (LABC). After the installation is complete they will register the installation with their issuing scheme provider and you will be issued with a certificate showing the work was completed and submitted by an authorised, registered installer.  Compliance can be registered through various auditing bodies, for example,  FENSA, CERTASS, BM TRADA, CORGI, BSI KITEMARK , ASSURE, to name a few

Building regulation documents cover the following aspects.

Thermal Heat Loss

Our environment is of paramount importance, and we are all responsible for our carbon footprint. It is, perhaps, obvious that energy efficiency within dwellings plays a major role, and reducing the amount of heat loss through the glazing in windows and doors helps impact on the environment, which is measured and expressed as a U-Value.  The U-value cannot be exceeded to be considered compliant. 

Any window installation must be able to demonstrate a maximum U-value of 1.6 W/m2.K and doors a maximum U-value of 1.8 W/m2.K

For further reading on the maximum U-Values permitted, refer to the Approved Document L, 1B, Table 1.


Windows and doors offer ventilation to rooms within a property and conditions apply to obtain necessary required levels of ventilation. The ventilation requirements depend on the use and also the size of the room concerned.  In rooms where increased steam may be produced, for example, kitchens, bathrooms, etc. higher or increased levels of ventilation may be required (such as an extractor or mechanical fan) than other rooms where suitable sized window openings may suffice or  background, commonly referred to as “trickle vents”, may suffice.

Safety glazing

High risk or critical areas must show high levels of consideration regarding safety glazing.

Any glazed area within a window 800mm or below from floor level must be installed using safety glazing.

Any glazed area within a window that is 300mm or less from a door and up to 1500mm from floor level, or any glazed area within any glazed door up to 1500mm from floor level must, again, be installed with safety glazing.

Fire Safety

Fire Safety need two areas of consideration:

Fire spreading between properties through unprotected areas.

Means of evacuation, in the case of a fire 

Unprotected areas

For external doors and windows to be considered compliant, they may need to offer increased fire resistance and doors be self-closing.  Windows may need to be fixed firmly shut in order to limit the risk of fire spread between adjacent properties.

The area of walls, doors and windows considered permissible to have reduced or undetermined fire resistance will be dependent on how close the proximity of these elements are to the property boundaries.

Means of escape

When replacing any existing  window, the opening should offer no less than the same size area which previously existed allowing the potential for escape should the need arise. In all habitable rooms above ground floor, fire escape hinges, (known as “egress” hinges) should be installed to allow a full 90o opening to allow means of escape.

The ability to quickly and safely evacuate must be considered for any new window to be installed to an extension or existing property. 

General criteria and regulations for egress windows:

·         Neither the Width nor the Height can be any less than 450mm

·         The Clear Openable Area can be no less than 0.33m²

·         The lowest point of the openable area to be no more than 1100mm above floor area.

·         There is only need for one window per room, generally.

Access to buildings

Consideration must be given to main entrance doors in a property that has been constructed after 1999. The threshold level cannot be made any worse that it originally was when first built. The threshold must remain level otherwise the works will not comply with relevant Building Regulations. This is to ensure people, including those with disabilities, continue to have the equivalent access to the dwelling.

Self Certification
    These regulatory bodies allow your supplier to register your installation as part of their self- certification scheme, meaning your installation is installed to building regulations
  • Legal, Safe & Compliant:
    You will receive a certificate of compliance direct from the regulatory body
  • Essential:
    If and when you ever come to sell your house, your solicitor will ask for a valid certificate.
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