Common Projects

Building an extension?

This is a complex building project so you should seek professional advice from an architect or building contractor before starting.

Watch our video: Do I need building regulations for my extension?

An extension will have a major effect on your home, garden and neighbours.

In drawing up plans you will need to look at how it would affect things like access to your home and garden, movement in and around your home and the natural light in existing rooms. You will also need to consider what building materials to use – particularly if your home was built using unusual construction techniques or materials.

Once you have decided your home is suitable for an extension you should get plans drawn up by an architect or building designer and get them approved by your local council’s building control team before starting work.

Plans & details should cover:

  • Foundations – ground conditions, depth, damp proofing and radon protection
  • Floors and walls – structure and strengthening, insulation and sound proofing
  • Roofs – flat or pitched, insulation, supports and beams, headroom
  • Drainage – connections to existing drains, manholes and water supply Electrics, power and heating Windows, doors and ventilation and disabled accessibility
  • Fire safety – escape routes and smoke detectors. In addition if an extension is planned to be two or more storeys, the plans will also need to cover
  • Stairs, handrails and bannisters
  • Sound-proofing – particularly in any sleeping accommodation
  • Fire escape – from upper floors

Watch our video: A building control case study of building an extension

Building a conservatory?

Many conservatories, summer houses, sheds and outbuildings can be constructed without building regulation approval. The general rule is that if they are small (less than 30m2), or are built of non-combustible material, or are separated from nearby buildings or land and do not contain sleeping accommodation they are exempt from the requirement to submit an application – although it is best to check with your local building control team before starting work.

Conservatories generally have to be constructed of mainly translucent walls and roofs and have an external type door separating them from the rest of the house.

Foundations and floors can be constructed in a variety of ways, but need to take account of ground conditions, trees and existing drains. It is also good practice to include insulation to make the conservatory easier to heat.

Conservatories constructed of uPVC should have frames that carry British Standard marks (BSEN 126908 and/or BS7412) to make sure they are strong enough to support the weight of the roof. Wooden conservatories will generally require treatment such as staining or oiling to maintain their reliability. You should check the timber comes from sustainable sources. Glazing should be toughened or safety glass. 

Watch our video: Conservatories basic rules

Garage conversions

Like home extensions, converting garages into a living space is a complex building project and you should seek professional advice from an architect or building contractor and check with your local council building control team before starting. Particular attention will need to be paid to the following when drawing up plans:

  • Foundations – often the foundations of a garage are not deep enough to handle the extra weight of floors, walls and ceilings so will need to be tested to see what strengthening is needed. Infilling door opening – should include suitable foundations, damp course, weather proofing and insulation.
  • Structural strength – often garage walls are of single layer of bricks which may not be suitable to carry an additional floor, new roof or additional insulation.
  • Weather proofing and insulation – the garage will need to be weather proofed and insulated if it is to be used as a living space.
  • Windows and ventilation – windows will need to meet minimum energy efficiency standards and have adequate ventilation provided Watch our video on garage conversion to find out more.

Watch our video: Garage conversions

Loft conversions

Converting the space under the roof of your home can be a cost effective way of creating extra bedrooms or living areas.  But not all lofts are suitable for conversion.  As a first step you should check the following:

  • Height: Is there enough room in your loft to stand comfortably?  For your loft to be classified as a bedroom once converted you will ideally need a minimum of 2m headroom – but remember this will be after new floors, beams and panelling have been fitted, which may take up another 300mm of headroom.
  • Floorspace: Is the floor area large enough to make a useable room?
  • Utilities: Would any chimneys, tanks, pipes or services require moving to create a usable space?
  • If your unconverted loft space is too low, or too small or has too many utilities it may still be possible to convert it, but it will be much more complex (and expensive).  And you should talk to your local building control team for advice.

Any loft conversion is a complex project, so you should get professional plans drawn up by an architect or building designer and get them approved by your local council’s building control team before starting work - you may also need Planning Permission so it's always best to check with your Local Authority Planning Department. The plans should cover:

  • Roof – structure (loading, supports and beams), materials, insulation and ventilation
  • Access – stairs (angle, width and height), fire escape, handrails and bannisters
  • Floors and walls – structure and strengthening, insulation and sound proofing
  • Electrics, power and heating
  • Windows and doors
  • Fire safety – escape routes and smoke detectors.
  • Bathrooms – connection to water supply and drains, ventilation

Watch our video on how the building regulations relate to loft conversions


These can often provide much needed light in your roof space where planning restrictions apply on the size or number of dormers. There are many proprietary brands available ranging from windows for means of escape in case of fire to windows giving access to open balconies. If you do intend to have a balcony you must ensure it is protected around the perimeter from falls and the decking is properly constructed to take foot traffic.

Storage spaces

You can use your existing loft space for storing lightweight household items without building control approval if you access the space by retractable ladder.  It is good practice to fit some loose boarding to provide a flat surface for the items. Ceiling joists are generally not designed to support heavy loads. So if you plan to use your loft space for storing heavy items or install permanent flooring or a proper staircase you may need to apply to your local council for building control approval.

Internal alterations and repairs

Here are some steps you will need to take before carrying out internal alterations.  Not all of these will require building regulation approval – the basic rule of thumb is that if the work involves load bearing walls, chimneys, fireplaces or walls around staircases then any alteration will require inspection and approval from your local building control team.  So talk to them as soon as you can.

If you are carrying out minor alterations such as replacing roofing tiles with the same type and weight of tile; replacing the felt to a flat roof; re-pointing brickwork; or replacing floorboards you will not need the work signed off by your local building control team.

Building, removing or altering walls

  • Internal walls have a number of functions: some keep the ceiling and upper floors up, some are there to help you escape from your home if there was a fire and others simply divide up space. 
  • Load bearing walls – these are fundamental to the structure of your home and you should get expert advice from an architect or structural engineer before they are altered, built or removed.  When removing a load bearing wall a structural engineer considers the loads on the wall and will design a beam and other supporting structures to safely transmit the loads to the ground.
  • Fire protection – walls around staircases offer protection to allow you to escape in the event of a fire, so altering these walls will mean you will probably need to take other measures such as fitting smoke alarms or upstairs windows suitable for fire escape to compensate.

Find out more by watching our video on alterations to the layout or structure of your home

Replacing windows

Generally window repairs such as replacing broken glass, fogged double-glazing, rotten sashes and rotten sections of the frame can be done without seeking building regulation approval.  But if you live in a conservation area, area of outstanding natural beauty or if your home is listed then you will need to get building regulation approval (and possibly planning permission too) for almost any glazing work – so check with your local building control team.

Fully replacing windows would usually require building regulation approval, but most work can be carried out using a FENSA registered installer.  They will carry out the work to the correct standards and provide you with all the relevant certificates on completion.

Bay windows and chimneys

Bay windows and chimneys are usually load bearing, so any alterations to them will need building regulation approval and you should seek expert advice from a structural engineer or builder before carrying out work.  If you want to remove a chimney breast, a structural engineer or architect will be able to assess the strength of the party or gable wall, chimney flue thickness and height to work out what kind of supporting measures to install in its place.

Working chimneys may require a flue liner or renovating to prevent smoke leaking into rooms and should be swept regularly to keep them working efficiently. If you plan to install a new wood burning stove it is important you follow the correct installation procedures.  More information on chimney repairs along with a register of competent contractors can be found at the National Association of Chimney Engineers

Last Modified: 18/05/2023
For more information contact:

Building Control

Tel: 01633 647300


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