Reroofing Regulations

roofing_regulationIf you want to insert skylights or roof lights or to re-roof your house, there is no need for planning permission. Roof alterations are allowed to the following conditions and limits:

  • Openings should be positioned at a fixed distance of 1.7 m above the floor; all side windows should be obscure-glazed
  • Alterations must not be erected beyond roof’s highest part
  • Alterations must not be positioned too far from the existing roof plane, i.e. 150 milimetres
  • There are other limits and regulations for solar panels when it comes to protected areas and on projections

Protected Species

When planning re-roofing you should consider how your work is going to affect protected species such as bats. If there are bats in your building, you may need a survey or even a licence.

There are some species in UK found in the wild which are protected by law. Nobody shall disturb or harm them. There are special regulations when it comes to bats. If you need certain licences or advice, you can search a number of sources on the Internet. Among the European protected species are: mink, grey squirrel, deer, bats, badgers, dormice, moles, otters, cormorants, herons, game birds, fish-eating birds, bullfinches, ducks and swans, red squirrel, wild boar, water voles, large blue butterfly, some mice ad rats, some rabbits, etc.

A wildlife licence is what you need in order to carry out any activity regarding a plant or animal that is protected by law. Unless you have such a licence, your actions will be considered illegal. This is why you need to find more information regarding animals and plants found near your property before commencing any construction work.

Building Regulations

Depending on the work to be done, there are two different sets of roof building regulations:

  • New roof construction
  • Existing roof work

Existing Roof Work

Normally, there is no need for a building regulations application to be submitted if you are planning to recover a small part of a flat roof or pitch (less than 25% of it), however you need approval if:

  • The area you are repairing/replacing is bigger than 25% of the area, which presupposes that the thermal insulation of the roof should also be improved
  • In the event of fire you will perform work on the new covering that is different than the existing one
  • Structural alterations will be carried out

Any roof alteration or removal could lead to movement due to affection of the roof work. In that case cracks could be caused as well, which could lead to a collapse of the roof. That is why it is important to be careful when performing this kind of work to ensure that there is no movement or cracks.

Regulation of other building projects

House Extensions
Loft Conversions
Fence Installation
Conservatory Construction
Kitchens and Bathroom Refurbishment
Boiler installation and Central Heating

Existing pitched roofs

A lot of timber elements are involved in the existing roof structure. Each of them is responsible for the roof being able to supporting the covering/tiles and transfer the weight (loads) that snow and wind create.

Here are the most common elements you’ll see in a pitched roof:

  • Ceiling joists – they are responsible for supporting the ceiling but they can also act as tiles. Joists are small in size, which means they cannot support the weight of a typical room.
  • Ties – these elements prevent the roof from an A-frame shape and from spreading. Ties are timbers which can be used as joists.
  • Struts – these elements are responsible for supporting the purlins. They are the diagonal roof timbers. One end is connected to a timber or a load bearing wall and the other to the purlin.
  • Purlins – these elements act like beams. They are pieces of timbers which you can see along the rafters.
  • Rafters – these elements support the battens and tiles. They are timbers.
  • Ridge Board – this is where the apex of the roof is formed.

Existing flat roofs

Flat roofs consist of joists. They are relatively simple in comparison with pitched roofs. There are panels that cover the walls, which are covered in coating such as felting.


A roof may need replacing after a period of time. In that case some work may have to be complied with the Building Regulations.

Pitch Roofs

Building Regulations approval may be required if you are planning to replace your current roof covering with one of a different material. This is applicable only if the new material is lighter or heavier than the existing one. The new roof covering must meet certain requirements in respect of energy efficiency and fire safety.

If the new covering is lighter or heavier than the original one, you may need to strengthen or modify the roof structure. Consult a surveyor or structural engineer about that.

Flat Roofs

There are types of repairs that do not require Building Regulations approval. Be it as it may, you may need to upgrade the insulation of your roof if it is to be replaced. This will help lower the amount of heat that was lost originally.

Energy efficiency

Roofs are considered to be thermal elements, so if you are planning to re-cover your roof, you need to improve its thermal insulation as well.


The purpose of a rooflight is to give more light to the building. Normally, it can be installed in both flat and pitched roof. If you want to install a new rooflight within your roof, you need approval under Building Regulations because:

  • This will affect and alter the structure of the roof.
  • Every rooflight has to be fully insulated against heat loss.
  • The roof has to be strong enough to carry the weight. If not, then it has to be strengthened.
  • You need to consider fire performance if the rooflight is positioned near a boundary.


Once you install a rooflight, the room has to be well ventilated. You can use the rooflight for background and rapid venting.

Weather Proofing

The edges of a rooflight and the glass itself need to be weather proof. Consult the manufacturers to learn how to achieve this. Usually, proprietary kits or lead flashing is used.


Installing a rooflight means that one or more of the joists or rafters will be cut away. When this is done, the rest of the rafters cannot be supported on their own, which means you need to add another element to support the cut ends. This is achieved by adding timber. Two pieces are needed. They are fixed together.

You may also have to strengthen the adjacent joists or rafters. It is achieved by installing another joist or rafter to support the weight.

Energy Conservation

Energy conservation is an important factor. You need to be energy efficient. To achieve this, you need to take several measures. You can insulate well the premises and thus lower the amount of heat that vanishes through doors and windows.

Be aware that you need to meet the Building Regulations requirements if you want to install doors and windows.

Thermal Elements and Insulation

Building Regulations approval is required when wanting to change significantly roodor floors, walls and other thermal elements. Also, you need to upgrade the thermal insulation. Since 2010, walls are considered thermal elements as defined by Building Regulations 2010′ Regulation 2(3).

If you’re in any doubt, make sure you check the Approved Document and Regulations. Before you start work, seek advice. It is important to know that doors, rooflights, roof windows and windows are not included in the definition of the term “thermal element”.

Conversion Projects

Every roof needs to be checked before any conversion projects begin. In cases where areas will be converted into useful space, roofs should be checked for thermal insulation and weather resistance.

If plasterboard should be added to the ceiling, the void may have to be ventilated.

Pitch roofs

With pitch roofs, you can install insulation between the joists of the ceiling. According to the material to be used, thickness varies.

In cases where there is no ceiling, insulation can be positioned between ventilation and rafters.

Flat roofs

Ventilation is required. There should be a gap of 50 mm between the ceiling and insulation. Eaves venting should also be incorporated.

Insulation can be positioned on top of the joists if the roof has to be re-covered. In that case ventilation is not necessary.

New Roof Construction

A new roof should:

  • be good enough to support weights (loads)
  • have adequate drainage
  • be ventilated
  • resist weather
  • be insulated
  • resist spread of fire

Generally, there are two roof construction types:

  • Flat roof: there is felting. It’s used to help rain water to go down the building and drain off.
  • Pitch roof: there are slates or tiles.


Ventilation is not necessary with every roof. Some roofs, especially those with a warm roof system, don’t have to be ventilated. When there is ventilation, this is called a cold roof system. When insulation is above rafters or joists, this is called a warm roof system.


The covering of a roof is an important element, that is why the materials used should be weather resisting and durable. In cases of a pitched roof, how shallow or steel the floor is determines the type of slate or tile you use. The roof should be able to limit the spread of a fire around if it is positioned near a boundary.


The weight (loads) come from numerous sources:

  • Weather: rain, snow, wind
  • Materials: insulation, felt, tiles
  • Maintenance: in order to repair the roof, a person should have access to it


Ceiling joints should be provided, as the timbers may spread apart. If you don’t want to use ceiling joists, ask an engineer to help you out. If you want to be able to see your roof, meaning to remove the ceiling, then you should use a different system. Consult a specialist about this.

Wind load

When there are strong winds, the roof should be able to withstand them. This is why it should be well tied down to the structure. It is done by adding straps with a cranked end. They should be about 1.2 m long. The end of these straps should be fixed to the wall plate.

Insulation/Thermal resistance

A roof can be insulated in two ways:

  • Cold Deck: insulation should be in between ceiling joists (for pitch roofs) or in between the rafters/joists. No ventilation required.
  • Warm Deck: insulation is placed first and then comes roof covering. Insulation should be on top of the joists/rafters. No ventilation required.

Pitch roof

  • Cold Deck: in that case insulation can be either in between the ceiling joists or in between the rafters. Depending on the manufacturer’s specification and material to be used, the insulation thickness varies. There should be vents as well. They should be installed from side to side along the eaves or to rear and front. Vents to be positioned along the ridge if insulation is in between the rafters.
  • Warm Deck: in that case insulation will be over the rafter followed by a felt. Then tiling and battering should be fixed down. Thickness varies again.

Flat roof

  • Cold Deck: insulation thickness varies as explained above. There should be made a 50 mm ventilation gap between underside of the roof and top of insulation. There should be ventilation openings as well. Before the plasterboard is applied, one additional element should be added; it’s a vapour membrane. The membrane is placed in the underside of the insulation.
  • Warm Deck: thickness varies as explained above. In that case a rigid type of insulation is used. The insulation is positioned over the joists followed by a board. Roof covering is placed next. It should be positioned over the ply.

Solar Panels

Most of the time installing solar panels does not require planning permission. It is part of the so called “permitted development”. However, there are certain rules and requirements that one should be familiar with before commencing work.

It may be a good idea to consult your local planning authority on any questions you may have regarding conditions and limits to be met.

Solar panels which are mounted within the grounds of a house

Conditions to be observed:

  • Once you stop using your panels for microgeneration, you need to remove them as soon as possible.
  • To reduce the effect on the building’s appearance, panels should be sited.

Limits to be met:

  • If your property is designated as a monument, you must not install panels.
  • If your property is positioned within the grounds of a listed building, you must not install panels.
  • You must not install panels above the roof’s highest part. The panels you install should be positioned 200 mm or less from a wall surface or the roof slope.
  • You must not mount panels to a wall that overlooks a highway if your property is situated in a World Heritage Site or a conservation area.

Solar panels which are not mounted on a building but stand alone

Conditions to be observed:

  • Once you stop using your panels for microgeneration, you need to remove them as soon as possible.
  • To reduce the effect on the building’s appearance, panels should be sited.

Limits to be met:

  • No part of your panel should be positioned close to a highway (if it bounds the house) if your property is situated in a World Heritage Site or a conservation area.
  • If your property is designated as a monument, you must not install panels.
  • If your property is positioned within the grounds of a listed building, you must not install panels.
  • Your panel should be placed at a significant distance from the boundary of the property (usually 5 m or more).
  • Your installation should be less than 4 metres higher.
  • Only one panel is considered permitted development. If you plan to install more solar systems, then you will need planning permission.

Building Regulations

There are building regulations if you want to mount a panel on your house.

Before you can install a solar panel on your roof, you need to have the strength of the roof checked as well as its ability to carry the weight. If the roof is not capable of carrying all the weight, then you may need to provide some strengthening work.

There are other aspects of the work too. For example, you need to consider building regulations in regard of electrical installation. Make sure you consult an electrician or installer before you commence work. The best thing to do is to discuss the matter with someone who is part of the Competent Person Scheme.

More information here and here.

The following guide should be regarded as an introductory and therefore it doesn’t provide legal information.

You are strongly advised to get in touch with your local planning authority for a complete peace of mind. Make sure that all your doubts, concerning the project are disproved before taking any building actions.