Essex garage conversions and builders - Planning and Building Regs

Planning & Building Regulations

Planning permission -

is not usually required, providing the work is internal and does not involve enlarging the building.

If your intention is to convert a garage into a separate house (regardless of who will occupy it), then planning permission may be required no matter what work is involved. We advise that you discuss such proposals with your local planning authority to ensure that any work you do is lawful and correctly permissioned.

Sometimes permitted development rights have been removed from some properties with regard to garage conversions and therefore you should contact your local planning authority before proceeding, particularly if you live on a new housing development or in a conservation area.

Where work is proposed to a listed building, listed building consent may be required.

Please note: The permitted development allowances described here apply to houses and not to:

Flats and maisonettes (view our guidance on flats and maisonettes)
Converted houses or houses created through the permitted development rights to change use (as detailed in our change of use section)
Other buildings

Is building regulations approval needed for a garage conversion? -

The conversion of a garage, or part of a garage, into habitable space will normally require approval under the Building Regulations.

General guidance on the performance expected of materials and building work in order to comply with the building regulations and practical examples and solutions on how to achieve compliance for some of the more common building situations can be found in the approved documents section.

The following pages give an indication of some of the elements normally required to satisfy the requirements of the Regulations when converting a garage.

These common work sections give an indication of several other elements normally required to satisfy the requirements of the Regulations when converting a garage:

Building Regulations: In-fill garage door -

As part of the garage conversion, it is likely that the original garage door will be in-filled with a new wall and possibly a window or door. As the foundation to the existing garage is not likely to be traditional (it's probably a shallow slab), a new foundation may be needed for the new wall. The existing foundation may be checked by digging alongside it until it's bottom is reached.

Foundations are required to transmit the load of the building safely to the ground. Therefore, all buildings should have adequate foundations (normally concrete), which will vary from one project to another depending on the circumstances of each case.

These foundations can be cast as deep-fill (filling most of the trench) or shallow-fill (where the minimum thickness to transfer the load to the soil is provided).

There are other types of foundations that may be used if the ground conditions do not make trench fill practicable. It is advisable to contact a structural engineer or speak to building control for further advice.

Factors to be taken into account of when designing a foundation:

Type of soil

The type of soil that the foundation will sit on is important for two reasons:

it should be able to bear the weight (load) of the foundation and the extension - different soils have different load bearing capabilities.
the way it reacts to variations in moisture content (such as in prolonged rainy or dry seasons) can lead to the soil expanding or contracting. This is a particular issue with some clay soils. These changes mainly occur up to a certain depth (typically about 0.75m) therefore foundations should be made deeper so they are not affected by ground movement (although see "Trees" below).

Adjacent structures

It is important to ensure that the excavation for the new foundation does not undermine adjacent structures. In general it is good practice to excavate at least to the same depth as the bottom of the foundation to the adjacent building. If the excavation runs alongside an existing footing then care will be needed - for example, by excavating and concreting the foundation in shorter sections to avoid undermining a whole length of an adjacent structure (also see guidance on the Party Wall Act).

Trees

Trees will draw moisture from the ground around them and beyond through their root system. As moisture is drawn from the ground it will have a tendency to shrink. How much the ground will shrink will depend on the following factors:

Type of soil - Clay soils shrink more than other types of soil. Therefore excessive movement of the ground could cause damage to the foundation and the structure it supports.
Size and type of tree - How large a tree or shrub will grow (its mature height), and the tree type will determine how much moisture it generally draws from the ground.

The presence of trees in clay soil areas can mean foundations need to be significantly deeper than might be first expected, although if the trees are far enough away, there may be no impact. Note: If existing trees are removed or significantly reduced in size, all or some of the moisture in the root system will be released over time into the soil and, if the soil is clay for example, could cause swelling of the soil and damage to nearby foundations and structure(s) supported.

Drains and sewers

As the weight (load) from the foundation of a building is transferred to the soil it spreads downwards outside the footprint of the foundation at a typical angle of 45 degrees. If a drain or sewer is within the area coveredby that 45 degrees area there is a risk that it could be affected by the load from the foundation and possibly crack. Therefore,the foundation excavation should normally be at least to the same depth as the bottom (invert) of the deepest part of the drain, sewer or its trench.

Size and construction of new building

The foundation will need to support more weight (load) from a two storey building compared to a single storey. This has a significant factor in determining design, particularly in respect of its depth and width. This is directly related to the bearing capacity of the soil supporting it. The width of the foundation is also governed by the wall thickness.

Ground condition

Generally the topsoil is taken away and good undisturbed ground is found i.e. ground that has not been built on. In some cases there are areas which have previously been backfilled, such as above where drains have been laid or to level a site, which consist generally of soft, mixed soil with foreign objects. The foundation can not be poured until undisturbed ground has been found.

Landfill sites

Some properties have been constructed on landfill sites which may require a more extensive form of foundation like piling as the depth of undisturbed ground could be many metres deep. An alternative may be a "raft" foundation. A structural engineer will be able to advise you further.

For health and safety reasons, care should be taken when working in trenches due to the risk of collapse causing potentially serious injury.

Building Regulations: Flooring -

The existing garage floor is likely to be strong enough for general domestic use, but may need to be upgraded to ensure it is adequate in terms of damp-proofing and thermal insulation. It may also be desirable to change the level of the floor to match the levels in the existing home.

The simplest way to achieve this would be to upgrade the existing concrete floor. Alternatively, if levels permit, an new timber floor could be constructed over the existing concrete floor.

Solid floor

The existing concrete floor can be used as a base, however a new damp proof membrane (DPM) will need to be introduced. DPMs come in solid or liquid form, the latter being a practicable solution for a garage conversion. Manufacturers will be able to advise. A suitable gauge damp proof membrane (DPM) and thermal insulation must be provided. These can be laid over the sand blinding or on top of the concrete.

Thermal insulation may be required and can be placed on top of the membrane (if a liquid membrane is used care should be taken to ensure the two materials do not react with each other - a separation layer may be needed). The exact details will vary depending on which products are used.

The floor can be finished with a layer of screed or a timber covering ("floating floor") the exact specification of which will depend on the insulation material used beneath. A screed is likely to need to be in the order of 75mm thick and should include a reinforcement mesh to prevent it cracking.

Care should be taken to ensure any existing airbricks for the main house are not obstructed by this work. If so, they should be extended through the new floor to external air.

Suspended Timber Floor

The existing floor level to the house may be quite high above ground, and in cases such as this it is more practicable to use timber joists, with a void underneath. A minimum gap of 150mm should be kept between the existing concrete ground and the underside of the timber. The timber floor joists must be sized correctly depending on their length. They are then laid across the shortest span from wall to wall with a gap underneath.

An intermediate wall with a small footing may be needed to reduce the span and keep the thickness of the floor joists to a minimum. A damp proof course (DPC) should be placed on the underside of timber. Insulation is then placed between the joists (thickness required depends on the product used). Air vents should be placed underneath to provide ventilation to the void and the air should be able to travel from one side of the building to the other.

Contaminated ground

In some areas, the ground could have a certain amount of contamination where gases form. If this is the case then this gas needs to be ventilated and a gas membrane will be required to stop it from entering the building.

Advice on this can be found in the Building Research Establishment (BRE) / Environment Agency report: BR 414 - Protective measures for housing on gas-contaminated land, 2001

For Radon gas, there is guidance the Building Research Establishment report: BR 211 - Radon: Guidance on protective measures for new dwellings, 1999

Building Regulations: Walls below ground level -

Depending on whether the foundation has been cast as deep-fill or shallow-fill, there could be a small or large amount of wall construction needed below ground level (substructure), on which the above ground walls (superstructure) will be built.

The principal requirement of the substructure is to ensure adequate support is provided to the superstructure. To remain effective the bricks or blocks and mortar should be resistant to frost and also to sulphates within the ground.

Building regulations: Ventilation -

Each new room in a house should have adequate ventilation for general health reasons. The type of room will determine how much ventilation is required.

When inserting a new internal wall care should be taken not to make any other matters, such as ventilation worse. If a new room is being created as a result of the addition of an internal wall then care should also be taken to ensure that the existing room is ventilated adequately. The general rules for ventilating a room are:

Purge - this is achieved by opening the window. The opening should have a typical area of at least 1/20th of the floor area of the room served, unless it is a bathroom which can be any openable size.

Whole Building - this is also known as trickle ventilation which can be incorporated in to the head of the window framework, or by some other means.

The area varies on the type of room:

habitable room - 5,000 mm² equivalent area
kitchen, utility, bathroom (with or without WC) - 2,500 mm² equivalent area

Both of these forms of ventilation are normally required, however alternative approaches to ventilation may also be acceptable, subject to agreement with the Building Control Body.

Mechanical extract fans

Any new kitchen, utility room, bath/shower room or WC with no openable window should be provided with a mechanical extract fan to reduce condensation and remove smells. The necessary performance of these extract fans is normally measured in litres per second (l/s) as follows:

Kitchen - 30l/s if placed over the hob and 60lt/s if place elsewhere.
Utility room - 30l/s
Bath/shower - 15l/s with a 15 minute overrun (after the light is switched out) if there is no openable window.
WC - 6l/s with overrun.

Alternative rates may be applicable if the ventilation is running continuously.

https://www.planningportal.co.uk/info/200130/common_projects/25/garage_conversion/6

Have you have tested your proposed project against the permitted development limits and conditions?

In most cases it should be possible to make a clear decision on whether your project is permitted or not. Remember, your proposal must pass all the tests necessary to be classed as permitted development. It is useful to tick off the limits and conditions as you work through them.

You should check with your local planning authority whether permitted development rights have been withdrawn by what are known as article 4 directions, and whether other consents, such as listed building consent, are needed. Remember also that many projects will be subject to the building control regime, whether or not planning permission is required.

If your project passes the permitted development tests you do not need to apply for planning permission and you may decide to go ahead with your project. Before starting work we strongly advise that you seek guidance from your local planning authority and building control body, and to seek professional advice where appropriate.

While it should be possible in most cases to decide whether or not a proposed project qualifies as permitted development there will inevitably be instances where the decision is less clear cut.

If there is any ambiguity or question over whether your proposal passes the permitted development tests you have a number of options. It may, for instance, be possible to alter your plans to ensure they meet permitted development limits and conditions.

For peace of mind you may choose to apply for a lawful development certificate (LDC). This is not the same as planning permission but is proof that your household building work is lawful.

This option is well worth considering even if you are sure your project is permitted development. If you should later want to sell your property, an LDC may be helpful to answer queries raised by potential buyers or their legal representatives. As such, it is important that all paperwork and records relating to your property are clear and up to date.

You can apply to your local council for an LDC using the Planning Portal's secure online application service. You will have to pay a fee.

If your project does not qualify as permitted development your remaining option is to apply for planning permission. Bear in mind that while a proposal may not meet permitted development criteria that does not mean it cannot be carried out. An application for planning permission allows the local planning authority to assess your proposal against a range of criteria and decide whether or not to approve it. You will have to pay a fee.

Regulations provided on -

Doors & Windows -

Since 1 April 2002 building regulations have applied to all replacement glazing. The regulations apply to thermal performance and other areas such as safety, air supply, means of escape and ventilation.

An external window or door is a "controlled fitting" under the Building Regulations and as a result of this classification these Regulations set out certain standards to be met when such a window or door is replaced.

You could use an installer registered with the relevant competent person scheme. A registered installer will be approved to carry out the work to comply with building regulations without involving local authority building control. When work is complete you will receive a certificate showing the work was done by a registered installer. More information about Competent Person Schemes can be found on the Gov.uk website.

Alternatively, you could use an unregistered installer or DIY, in which case approval can be sought from the relevant Building Control Body – either at your Local Authority or an Approved Inspector. They will check the replacement window(s) or door(s) for compliance and, if satisfied, issue a certificate of compliance.

Thermal Heat Loss

Dwellings are required to be energy efficient. A method of achieving greater energy efficiency is to take steps to reduce the amount of heat that is lost through the glazing in both windows and doors.

If you are to install windows and doors you should be aware that they need to comply with the requirements of the Building Regulations in relation to the amount of heat that can to pass through the glass and framework, which is measured as a U-Value. This U-value should not be exceeded. For information on the maximum U-Value allowed please refer to Approved Document L-1B, Table 1.

Safety glazing

Safety glazing should be provided to any glass in a critical area. Below is a list giving general view as to when safety glazing is required:

Any glazed area within a window below 800mm from floor level
Any glazed area within a window that is 300mm or less from a door and up to 1500mm from floor level
Within any glazed door up to 1500mm from floor level.

Ventilation

Windows and doors provide ventilation to rooms within a dwelling and rules apply to how much ventilation. The type and extent of ventilation will be dependent on the use and size of the room. For example, rooms where steam will be produced (kitchens, bathrooms, utility rooms etc) should be provided with higher levels of ventilation (normally mechanical fans and windows) than other rooms where suitably sized window openings and background ("trickle") ventilators may suffice.

Fire Safety

There are two aspects to be considered:

Fire spread between properties through "unprotected areas"
Means of escape in case of fire

Unprotected areas

External doors and windows may need to have fire resistance and (in the case of doors) be self-closing or (in the case of windows) be fixed shut to limit the risk of fire spread between adjacent properties. The area of walls, doors and windows permitted to have reduced or undetermined fire resistance (known as “unprotected areas”) will be dependent on how close these elements are to the boundary.

Means of escape

When replacing any window, the opening should be sized to provide at least the same potential for escape as the window it replaces. If the original window that is being replaced was larger than necessary for the purpose of escape, then the new window opening could be reduced down to the minimum as specified in the criteria below.

The means of escape should be considered for any new window installed to an extension or existing dwelling. If an escape window is required then criteria set out below should be followed. It is also generally good practice to replace any window on the first floor that is not used as an escape window with an escape window.

See below for the general criteria for egress windows:

Width and Height - Either of these are not to be any less than 450mm
Clear Openable Area - No less than 0.33m²
Cill height - The bottom of the openable area should be no more than 1100mm above the floor area.

Only one window per room is generally required.

Access to buildings

When replacing main entrance doors in a dwelling unit that has been constructed since 1999, it is important to ensure that the threshold remains level otherwise the works will not comply with the Building Regulations as it would be making the threshold worse than it was when constructed. This is to enable people, including those with disabilities, to have continued access to the dwelling.

Drainage -

This section has been written for homeowners who may be considering building an extension or making alterations. It outlines the main impacts that drainage may have on your project. If you decide to proceed with your project, your builder will need to look at Approved Document H for detailed advice on how to comply with building regulations.

What is drainage?

There are two systems of drainage that you need to think about: 'foul' and 'surface water'. In general, these two systems should be kept separate.

Each of these has above-ground and underground elements.

Foul drainage carries the used water from toilets, sinks, basins, baths, showers, bidets, dishwashers and washing machines. The above-ground pipework is referred to as sanitary pipework; the underground pipework is referred to as foul drains and foul sewers.
Surface water drainage carries rainwater (and melted snow and ice) from hard surfaces. The above-ground system of gutters and rainwater pipes is referred to as roof drainage; the underground pipework is referred to as surface water drains and surface water sewers.

What is the difference between a drain and a sewer?

In general, a drain serves a single property whereas a sewer serves more than one property.

Private sewers are owned by the properties they serve. Public sewers are owned by the sewerage undertaker (whose address can be found on your sewerage bill). Building work on and around a sewer needs permission of the sewer owner.

Why do I need to think about underground drainage?

You may have to change your plans to suit the depth and location of the underground drain or sewer that you intend to connect to.

If you intend to build over or close to a public sewer, you will require written agreement from your sewerage undertaker, so you should consult the company at the earliest planning stage of your building work.

Building over an existing drain or sewer can damage pipes, so that they leak or block, potentially leading to odour nuisance, health problems and environmental damage. It also makes it more difficult, time consuming and expensive to clear blockages and repair or replace faulty drains. So if there is an existing drain below, or close to, your proposed extension, it may need to be moved or protected, which is likely to increase the cost of your project.

The route of the drain should avoid obstructions (eg. ponds or outbuildings) and keep away from foundations, so may need to be longer and have additional access chambers, rather than running in a straight line. Approved Document H gives guidance on additional measures needed where drains have to run close to foundations.

In order to carry the flow and to avoid blockages, the drain or sewer that you intend to connect to generally needs to be at least 0.8m lower than the ground floor level. If it is less than this, you should seek advice from a builder, architect or drainage engineer.

How can I find out the location of underground drains and sewers?

Maps of public sewers can be inspected free of charge at the offices of the sewerage undertaker or local authority. Private sewers and drains are not normally mapped and their location needs to be found in other ways, as described below.

Drain covers give an indication of drains below. By lifting the cover, it may be possible to see the direction, size and depth of pipes but do not enter the chamber (which can be filled with toxic gas) and ensure that the cover is replaced securely.

Locations of rainwater pipes, sanitary pipework stacks and external gullies can indicate where their underground drains are likely to run.

There are many firms which can carry out CCTV surveys that will indicate the condition of the drains as well as their location and depth.

You are strongly advised to seek advice from a builder, architect, drainage engineer or your local authority building control department before committing to or commencing work.

I’m thinking about increasing the size of my roof.

You may need to increase the size of your gutters and rainwater pipes, or add new rainwater pipes. Information on sizing gutters and rainwater pipes is given in Approved Document H.

Additional rainwater pipes can discharge onto the ground, or into new or existing underground pipework. If you decide to allow rainwater pipes to discharge onto the ground, you need to make sure the water will not damage foundations (eg. by encouraging it to spread out over a wide area) or flow onto neighbouring property (eg. by providing a slight lip at the boundary).

A larger roof area will increase the amount of surface water. It is preferable to keep the extra volume on site, in order to avoid increasing flood risk elsewhere. Rainwater can be kept on site by using a soakaway or some other way of allowing it to soak into the ground (referred to as infiltration), or stored and used for toilet flushing or garden watering (known as rainwater harvesting). Approved Document H gives advice on where to site soakaways, how large they should be and how they should be built.

Where it is impractical to use infiltration (eg. because of nearby foundations, impermeable or contaminated ground, or high groundwater), it is preferable to discharge it to a watercourse or, failing this, to a surface water sewer or, as a last resort, to a combined sewer. Surface water must not be discharged into a foul drain or sewer.

I’m considering a new patio or driveway.

In order to avoid increasing flood risk elsewhere, it is preferable for these to be sloped towards permeable ground or to be made of pervious materials. Pervious materials include both porous materials (eg. as reinforced grass or gravel, porous concrete or porous asphalt) and permeable materials (eg. clay bricks or concrete blocks, designed to allow water to flow through joints or voids). As well as minimising environmental impact, this avoids the cost of drainage.

Surface water from hardstandings must not be allowed to run onto the highway, where it could lead to accidents or cause a nuisance.

Where it is impractical to drain onto pervious ground or use a pervious paving, it is preferable to keep the extra surface water on site, in order to avoid increasing flood risk elsewhere. This can be achieved by using a soakaway or some other way of allowing it to soak into the ground (referred to as infiltration).

Approved Document H gives advice on sizing soakaways. Where it is impractical to use infiltration (eg. because of nearby foundations, impermeable or contaminated ground, or high groundwater), it is preferable to discharge it to a watercourse or, failing this, to a surface water sewer or, as a last resort, to a combined sewer. Surface water must not be discharged into a foul drain or sewer.

What size pipes do I need from kitchen and bathroom appliances?

Pipes need to be sized for the flow of water, to minimise the risk of blockage and to allow air movement. Advice on pipe sizes is given in Approved Document H.

Sanitary pipework should be designed with access hatches, or be capable of being dismantled, in order to deal with blockages.

Rodding eyes and access chambers should be used to enable all parts of the underground drainage to be cleared and to allow removal of blockages.

Do I need a ventilating pipe through the roof?

Sanitary pipework needs to be ventilated to avoid air from the pipework and drains from escaping into the building.

The normal way of doing this is to extend the pipework (known as the ventilating pipe) to outside the building, leaving the end open (but protected with a mesh to prevent birds getting in). To stop smells entering a building, the open end of the ventilating pipe should be at least three metres to the side of, or extended to 0.9m above, any opening into a building.

If the drainage is already ventilated, additional ground floor appliances (eg. a WC and washbasin) may be connected directly to the drain without a ventilating pipe.

It may be possible to use proprietary valves to avoid the need for ventilating pipes.

Electrics -

If you are carrying out electrical installation work in your home or garden in England and Wales, you must comply with the rules in the Building Regulations. It is best to use an installer registered with a competent person scheme (a ‘registered competent person’) who can self-certify compliance with the Building Regulations.

If an installer is not registered, then certain riskier jobs (identified as ‘notifiable’ in the Building Regulations) will need to be inspected, approved and certificated by:

a building control body (your local authority or a private approved inspector), or
in England only, an electrician registered with a third-party certification scheme (a ‘registered third-party certifier’).

The building control body or registered third-party certifier must be notified before work starts.

Notifiable jobs include:

the installation of a new consumer unit or fuse box
the installation of a complete new circuit – for example a ring or lighting circuit, or a new circuit for a cooker, shower or immersion heater
alterations to existing circuits – such as adding an extra power point or lighting point – but only in ‘special locations’. In England, special locations are the spaces around baths and showers. In Wales, special locations include also kitchens and outdoors.

Most repairs, replacements and maintenance jobs, and alterations or additions to existing circuits outside special locations, are not notifiable.

The Building Regulations set out overall criteria and requirements to ensure electrical safety. Approved Document P provides further practical guidance for undertaking this type of work. You should bear in mind that any electrical work you carry out within your home, garden, garage, shed or other storage building must comply with the requirements of the Building Regulations. If you are unsure about the requirements, you should contact your local authority’s building control department.

All electrical work should follow the safety standards in BS 7671 (the 'wiring regulations'), which can be found on the British Standards Institute (BSI) website.

These rules have been introduced to help reduce the number of deaths, injuries and fires caused by faulty installations.

The Building Regulations set standards for electrical installation work only in relation to dwellings (houses, flats etc). If the work is carried out in industrial or commercial buildings it is covered by the Electricity at Work Regulations 1989. The Health and Safety Executive (HSE) is responsible for making sure that electrical installation work in these kinds of buildings is safe and if you have any queries about work in these buildings you should contact the HSE.

The Building Regulations do not restrict who may carry out electrical installation work. If you want to do the work yourself you should make sure that you know what you need to do before starting any works. There are a number of reputable guides that you can use to help you.

The Building Regulations do not set standards for the safety of electrical appliances but they do require that fixed connections of appliances are safe.

External Walls -

If you want to re-render or replace timber cladding to external walls, building regulations may apply depending on the extent of the work.

Where 25 per cent or more of an external wall is re-rendered, re-clad, re-plastered or re-lined internally or where 25 per cent or more of the external leaf of a wall is rebuilt, the regulations would normally apply and the thermal insulation would normally have to be improved.

If you want to insert insulation into a cavity wall the appropriate requirements will be applied to ensure the insulation material is suitable, and that in the case of some foam insulants the risk of formaldehyde gas emission is assessed.

Walls can be constructed in various ways by using timber frame structure or masonry structure.

If using a masonry structure then two forms of construction can be used:

Cavity Wall

This is where there are two skins of masonry, the outer skin can be of brickwork or blockwork and the inner skin is generally of blockwork

The gap between the two skins will vary depending on the type of insulation that is to be used. To stop the two skins from falling away from each other they should be tied together using wall-ties at appropriate centres. These ties should also be resistant to corrosion.

The bottom of the cavity should be filled with lean mixed concrete with a slant towards the external skin or have a cavity tray installed that also slants towards the outer skin to ensure any moisture that could get inside the cavity will be directed away from the inner skin.

Solid Wall

This is where there is only one skin of masonry which can consist of brick/blockwork

The high standards of thermal insulation needed in buildings means that it is more difficult to achieve those standards with solid masonry wall construction. Solid blockwork constructions may meet the requirements if allied with other insulation products and surface finishes.

Existing External Walls in Conversion Projects

Existing walls will need to be checked for their adequacy in terms of:

Weight (Loading) and structural stability
Weather resistance (including Damp-proofing)
Thermal resistance and changes to 'thermal elements'

If they need to be upgraded, this may well involve the addition of a new internal skin - possibly constructed of lightweight studwork. The detail at the foot of the new skin will need careful planning to ensure that damp-proofing arrangements are sound and that any new timbers are protected from damp.

Internal Walls -

If you wish to build a new internal wall, remove an internal wall, or form an opening in an internal wall, building regulations will normally apply.

There are typically two types of internal walls:

Load Bearing - where the wall provides separation between rooms and is also required to transfer loads from other parts of the structure, roof and floors etc., down to the foundations - view further details below.
Non-Load bearing - walls that provide separation between rooms and are not required to transfer loads

New Internal Wall(s)

Work to provide a new internal wall generally requires approval under the Building Regulations 2000

In the case of conversion projects:

adequate separation - in terms of fire resistance and thermal insulation - should be provided between the new habitable space and the remaining space.
Any door provided in such a wall should have adequate fire resistance and be self-closing. Depending on the use of the new habitable room, the new separating wall may also need to provide sound insulation.

Removal of Internal Wall(s)

Care should be taken before removing any internal wall. These walls can have a number of functions that could affect the building and the safety of the occupants within the building.

Roofs -

If you want to carry out repairs on or re-cover less than 25 per cent of the area of a pitch or flat roof, you will not normally need to submit a building regulations application. You will need approval, however, if:

You carry out structural alterations
The performance of the new covering will be significantly different to that of the existing covering in the event of a fire
You are replacing/ repairing more than 25 per cent of the roof area, in which case, the roof thermal insulation would normally have to be improved.

The removal or alteration to any roof elements could affect how the roof works and cause movement to occur. Movement could cause cracks to occur in the walls and, possibly, the eventual collapse of the roof. When performing work on any roof, care should be taken to ensure the roof will continue to perform effectively and without any movement.

Existing Pitched Roofs

The existing roof structure that forms the loft space has a number of timber elements that make the overall pitch. Each element enables the roof to span across the building and support the tiles/covering on top as well as being able to transfer the loads (weight) created by any wind and snow down to the walls.

Listed below are the typical elements of a pitched roof:

Ridge Board – This forms the apex of the roof and is where the rafters are fixed to both sides.
Rafters – These are the timbers that form the main pitch to the roof and support the tiles and battens.
Purlins – These are long pieces of timbers that are normally seen half way along the rafters and act like beams to reduce the span (unsupported length) of the rafters.
Struts – These support the purlins. They are fixed at an angle with one end connected to the purlin and the other on to a load bearing wall or a timber spread across ceiling joists. These are the diagonal timbers seen in the roof.
Ties – These are timbers which stop the roof from spreading and form an A-frame shape. They can either be the ceiling joists (as described below) or can be fixed half way up usually above the purlin and are fixed horizontally from front to back. (Common in terraced houses).
Ceiling Joists – These can act as ties, but mainly support the ceiling below. Their sizes are usually relatively small and will not be able to take the load of any typical room used in a house.

Existing Flat Roofs

Flat roofs are more simple and generally consist of joists that span the gap between two walls. These are covered by panels which, in turn, are covered in felting or other such coatings as required.