The Building Regulations are performance standards and deal with the health and safety of the occupants and other technical issues such as the conservation of fuel and access to and about buildings.

Almost all home extensions will require Building Regulations approval, even if they do not require planning permission. There are a number of guidance documents referred to as 'Approved Documents' that contain practical ways and explanations of how to comply with the functional requirements of the Building Regulations.

We have summarized these below and given examples of how these will apply to an extension project:

Structural stability (Part A)

This regulation deals with the buildings ability to carry anticipated loadings and the general stability of the structure. This will include checking that foundations are adequate (including the effect of nearby trees), any piers and steel beams are strong enough and that the extension is able to withstand wind and snow loadings.

For many extensions, you will need to appoint a structural engineer to provide calculations for certain elements of the building and these will form part of the application documents.

Fire Precautions (Part B)

This part of the regulations deals with controlling the materials used in the construction of an extension and also making sure that buildings can be evacuated without loss of life. It also covers the risks attached with the spread of fire from one building to a neighbouring building.

When designing an extension, consideration must be given to the ease of escape in the event of a fire and problems caused by creating inner rooms. In some cases, windows will need to be a certain size to provide a means of escape.

This section also deals with the provision of smoke alarms and ensuring that, in certain locations, materials used are able to withstand the spread of fire – e.g. fire resistant doors between the habitable space and a garage.

The prevention of dampness (Part C)

This regulations deals with site preparation and the resistance to contaminants and moisture. It deals with the general ability of floors, walls and roofs to withstand rain and groundwater.

You will be required to provide a damp proof membrane in any new floor and damp proof courses to various parts of the walls. The extension roof should be properly weatherproofed.

Toxic substances (Part D)

This section deals with toxic substances that will need to be limited in any extension.

Sound resistance (Part E)

Any extension must be properly sound-proofed and this part of the regulations deals with the minimum standards required for both air-borne sound and structure-borne sound.

For example, for two storey extensions, you will normally be required to provide sound insulation within the first floor construction. of walls and floors between dwellings.

Ventilation (Part F)

Ventilation plays a major part in modern building design and this part of the regulations deals with the requirements you will need to put in place to avoid condensation and other health risks.

All habitable rooms will need to have provision for natural ventilation to the outside air (by use of a door or window) which is general 1/20th of the floor area and kitchens, bathrooms and utility rooms will also need mechanical extraction fans.
This regulation also deals with the provision of ventilation to roof spaces.

Hygiene (Part G)

This part of the building regulations deals with sanitary appliances, water supplies, hot water systems and the provision of washing facilities.

You will need to define and obtain approval for any changes to your existing system and ensure that any new hot water system meets with the requirements.

Drainage and waste disposal (Part H)

Any new drainage or alterations to the existing drains required to build your extension will be covered by this part of the Building Regulations.

Both rainwater (storm) and foul drains are covered and these requirements set standards for minimum falls, cleaning and access provisions, safe disposal of wastes and rainwater, ensuring that they meet health and environmental standards.

You will need to provide minimum pipe sizes for any new waste pipes from bathrooms or kitchen/utility rooms and you may be required to provide additional manholes where new connection are made.

Heating appliances (Part J)

This regulation deals with the provision of any new heating appliance such as boilers including the safe discharge of flue gases

Stairways (Part K)

If your extension includes a new staircase or a ramp, then it will be covered under this part of the regulations.

There are numerous requirements on any new staircase including the following:

• The maximum angle of the stairs
• The maximum rise (height) of an individual step
• The minimum length (going) of an individual step
• The provision of landings
• The provision of balustrading and the height of handrails
• Limitation on doors opening near to a staircase

Conservation of fuel and power (Part L)

All extension will have requirements covered by this part of the regulations that essentially deals with thermal insulation requirements. This part of the regulations is subject to continual change and there are so many requirements, the documents are split into two sections L1 and L2.

Any extension will have to meet minimum standards for floor, wall and roof insulation and the regulations also cover maximum glazed areas and double glazing requirements.

Access (Part M)

This part of the regulations deals with access to buildings and facilities for disabled people.

The safe positioning of glazing (Part N)

Any new glazing to windows, doors, etc that is installed will have to meet minimum standards and these are covered here.

Electrical safety (Part P)

This is the latest part of the regulations and any new electrical works are now controlled.

Most extensions will utilize an approved electrician who is able to self-certify his works but a test certificate will be required in order to get the building regulations completion certificate.

Summary

The above summaries demonstrate that the Building Regulations are wide ranging and extensive documents and really should be dealt with by a professional architect or designer in order to ensure that your new home extension complies.

Generally, the regulations apply to most building works where a new building is constructed or an existing building is altered or extended. These are summarized below and any person carrying out building work needs to ensure that work complies with the regulations.

• the erection or extension of a building;
• the material alteration of a building;
• the provision or extension of a controlled service or fitting in or in connection with a building;
• work relating to the material change of use of a building;
• the insertion of insulating material into the cavity wall of a building;
• work involving the underpinning of a building.
• replacement windows.

There are some types of work which will be exempt from the Building Regulations and an application will not be necessary as shown below:

Garages

The construction of a new attached carport, open on at least 2 sides, would not normally require Building Regulations if it is less than 30m2 in floor area. Construction of a detached garage less then 30m2 would not normally require Building Regulations approval, subject to certain criteria.

Sheds

Construction of a small detached building such as a garden shed or summerhouse in the garden will not normally require Building Regulations if the floor area of the building is less than 15m2. If floor area is between 15 & 30m2 you will not normally require Building Regulations providing that the building is either at least 1m from the boundary or it is constructed of substantially non-combustible material.

Manhole & drains

If you wish to repair or replace an existing drainpipe, manhole or associated fitting, approval under the Building Regulations is not normally required if the replacement is like for like.

Windows & doors

If you want to replace broken, fogged double glazing units, rotten sashes or rotten sections of the main frame members, Building Regulations will not apply.

Porches

Construction of a porch built at ground level under 30m2 in floor area is normally exempt from the need to make an application provided that the glazing and any fixed electrical installation complies with the applicable requirements of the Building Regulations.

Work on the roof

If you want to carry out repairs or recover a pitch or flat roof of an area that is less than 25% you will not normally need to submit a Building Regulation application.

Conservatories

A conservatory built at ground level and under 30m2 in floor area is exempt provided that glazing and any fixed electrical installations comply with the applicable requirements of the Building Regulations.
We would always recommend that you speak to your local council’s Building Control office to check on any specific project.

Sample coming soon