Extending Your Home

Almost every property has got potential for an extension — and all it takes to transform your home is a bit of imagination (and the funds to pay for the work). Whilst a well thought out extension can add far more value to a property than it costs to complete, not every extension will be financially worthwhile, as some properties are already at their maximum ‘ceiling’ value for their location. When considering whether or not to extend, establish the likely cost, relative to any increase in value, and take this into account. If you plan to move house in the near future, then it may only be worth adding an extension if it will significantly increase the value of your home. If you plan to remain in the property for the foreseeable future, then the lifestyle benefit of the extra space is likely to be a more significant factor.

WHERE TO EXTEND

Look at the shape of your property and the land it stands on; if you do not have a location plan you can get one from HM Land Registry (www.hmlr.gov.uk)  for £3. Look to see where there is room to extend without spoiling your garden, and if room is limited, consider whether next door might sell additional land.

Extensions don’t have to be built onto the sides or back of your home — think about the potential to add new storeys, by converting the loft, or a cellar. Converting existing space is usually less expensive than adding new space. It may be possible to redesign the roof and add another storey on top of your house, especially if you live in a bungalow. This can work if you live in a flat, too.

In high-value property areas, such as Central London, it can make sense to dig out a new basement level underneath your home. The costs are high, but so are property values.

SHAPE AND FORM

First, consider the external appearance of any extensions and their possible effects on the adjoining properties and the street scene — both of which will be considerations for the planners if you have to apply for permission. Oversized and badly placed extensions can result in a loss of daylight and outlook for adjoining neighbours. A poorly designed extension will also spoil the appearance of your house and detract from its value.

It is worth bearing in mind that multi-storey extensions are, on average, more cost-effective than single storey additions. As well as spreading the cost of the more expensive elements of construction – the foundations and roof – multistorey extensions will have less impact on outdoor spaces. If you plan to add extra storeys to an existing building, the foundations must be capable of carrying the increased loading. Structures built after 1978 should have been built with footings capable of carrying additional storeys and there may be records and plans. If not, the building inspector will want part of the foundations inspected. If they have to be strengthened by underpinning, this can prove expensive.

PERMITTED DEVELOPMENT RIGHTS

You should not need to apply for planning permission if the extension:

• Is not any nearer to a highway than the nearest part of the original house, unless there would still be 20m clear space between the house and the highway. ‘Original house’ means the house as originally built, as it was on the 1st July 1948, or the cut-off point set by the local authority. 
• Covers no more than 50% of the area of land around the original house, taking into account outbuildings. 
• Will not be higher than the highest part of the original house’s roof. 
• Will be no more than 4m in height (measured from the highest ground level position beside the extension) and is within 2m of the property boundary. 
• The volume of the original house will not be increased by more than 30% or 70m2 for a detached house; or 10% or 50m2 for a terraced house or any house within a National Park, Conservation Area, Area of Outstanding Natural Beauty, or the Broads.
• Is not a listed building or in a Conservation Area, in which case further restrictions apply. 
• Is not a flat or maisonette.

When assessing what is allowed under Permitted Development rights, the volume is usually calculated using external measurements for the extension. The volume of the original house is usually calculated from external measurements, including roof space, and outbuildings attached, or within 5m of the house, providing they are ‘original’.

VAT

VAT is payable on extensions and remodellings to ordinary houses at the standard rate of 17.5%. You can save on labour by using non-VAT-registered subcontractors. VAT on listed buildings is reduced to 0% for ‘approved material alterations’ when undertaken by a VATregistered contractor.Work to houses empty for 10 years or more is largely free of VAT.Work to houses empty for three years or more is charged at 5% when undertaken by a VAT-registered contractor. Renovation work that involves a change in the number of dwelling units is also charged at the reduced rate of 5%. Contact HM Revenue & Customs for more details or visit www.hmrc.gov.uk.

THE BEST USE OF SPACE

You probably already have ideas about where you need extra space. Start by creating a plan of the existing house, either yourself, or by getting a measured survey by a surveyor (see www.rics.org.uk). The key spaces to focus on are:

• The kitchen, which should ideally be spacious and have a separate utility room, somewhere for a table and chairs for informal dining, and perhaps an informal living area, too
• The number of bedrooms, as this usually adds most value (up to a limit) 
• The number of bathrooms, with at least one bathroom for every three bedrooms plus an en suite to the master 
• Living space — a family home will ideally have two living spaces
• Circulation (hallways, corridors and stairs) that is space-efficient and flows well Access and circulation are critical in getting the design right. Here are some common design mistakes to avoid at all costs:
• Excessive corridor space
• Narrow corridors or pinched access
• A second staircase unless essential
• Bedrooms accessed through other bedrooms
• Ground floor bathrooms, except in bungalows or flats
• Dead space, such as inaccessible niches, dead-end corridors etc
• Rooms that are too narrow to be practical, or have odd proportions • Isolating rooms from natural light by losing windows
• Mixing private space (bedrooms) with public space (kitchen and living rooms)
• An imbalance between bedrooms and bathrooms
• A conservatory that looks onto a fence or other unattractive feature

DESIGN

Before investing in the services of a designer, discuss your ideas with a planning officer who will be able to advise on whether or not you need to make a planning application. They can also provide guidance on the key planning rules that you will need to consider, although your designer should be aware of these.

Minor extensions may not require a planning application in certain circumstances — some are automatically granted consent under the General Permitted Development Order (GDPO). Details can be found on your local authority website, or at www.opsi.gov.uk.

Your designer should initially produce sketches, and once you have agreed a layout they will produce planning drawings. It is fine to produce the drawings yourself for a basic extension, but it would be a false economy on a larger project.

Most local authorities will expect extensions to be designed in sympathy with the existing house and many produce supplement design guidance, which forms an informal part of the local development plan. However, there is no reason why you have to follow the guidelines: you can opt for a strongly contrasting style for your extension, providing you can justify it as a good design that enhances the street scene.

The chances of getting something more radical approved at the rear of a property are greater than at the front facing the highway. The decision will depend on objections from neighbours, the views of the planning officers, and those of the planning committee.

Where an extension is being constructed under Permitted Development rights, you can please yourself about the design, regardless of what the planners or neighbours think.

FINDING A DESIGNER

It is sensible to meet several potential designers to view their previous work.

Find a designer with experience in projects of a similar size, style, scope and budget to your own. As well as planning drawings, you will need to produce construction drawings, showing compliance with the Building Regulations and giving builders details of materials.

Registered architects, architectural technologists, surveyors, engineers, interior designers, technical drawers and draftsmen all offer design services. Each discipline has different training and different areas of expertise. The different disciplines charge different fees.

FINDING A BUILDER

Although personal recommendation from someone you know and trust is by far the best way to find a building contractor, always make the same checks on every contractor on your list, regardless of how you got their name. The fact that they may be a member of a trade association or body is no guarantee of the quality of their work or their financial stability. Get references and always check them.

Check References: 

• What was the builder like to work with? 
• Did they do the required work? 
• Was the work completed to a satisfactory standard? 
• Were any problems overcome? 
• Was the project completed on time? 
• Was the project completed on budget? 
• Were they neat, tidy and reasonably quiet? 
• Would they use them again? 
• Are they happy to recommend them?

PLANNING PERMISSION

Most local authorities will now accept online applications (www.planningportal.gov.uk). The fee for an extension application is £165. If your home is listed you will also have to apply for Listed Building Consent, and/or Conservation Area Consent.

The local authority will notify you of the date by which they must make a decision, which is within eight weeks by statute, although they can ask for longer. They will also notify the neighbours, and the parish council (community council in Scotland and Wales).

There then follows a four-week public consultation period during which neighbours etc are invited to view the plans and post comments. Meanwhile the local authority will approach statutory consultees.

Monitor progress by staying in touch with the planning officer, to see whether they will recommend approval. If not, find out why and make changes to get their support.

If the officers recommend approval and there are no objections, the plans will usually be approved under delegated powers. If there are objections, or if the plans are called in by a councillor, then the application will be determined by the planning committee. They may decide to defer the decision, to consult a panel of architects or to obtain further information, but usually they will take a vote there and then.

If the application is approved you will be notified in writing, with details of any conditions.

If the application is refused, the council must explain the reasons. You can then reapply with revised plans, free of charge, within one year of the original application, or you can appeal. For details, visit your local authority website or www.planning-inspectorate.gov.uk.

THE BUILDING REGULATIONS

Any new building work will require Building Regulations approval from the local authority.

You can either make a Full Plans submission, which will take around five weeks for approval, or you can issue a Building Notice 48 hours before commencement of works. Submitting Full Plans gives you and your designer a chance to resolve all details and the specification to ensure compliance before work starts, whereas by working under a Building Notice you are taking a risk — anything that does not comply will, unfortunately, have to be altered.

Since the introduction of Approved Document Part L1B — Existing Dwellings, the Building Regulations have been extended so that existing buildings, where practical, have to be insulated when any material alterations are being carried out. Where practical, floors, walls and roofs must be upgraded. There are exceptions for listed buildings and also for buildings of historic or architectural interest. Part L1 may also have implications for your design, especially if you want to include large areas of glazing. The best way to overcome this is to use the Carbon Index method of complying with Part L, which allows you to use large areas of glazing and to offset the energy loss against improved levels elsewhere.

HOW MUCH WILL IT COST?

To get an idea of costs, take a look at similar projects undertaken by other homeowners. Your designer will also be able to give you an idea of typical costs and, once you have plans, you can get a price from a builder by providing the following tender documents: 

1. Drawings detailing the scope of the project
2. Specification and details of materials
3. Bill of quantities (all materials itemised)
4. Contract — legal documents

Alternatively, hire a quantity surveyor who will use standard measured rates to produce a cost analysis. You could also do this yourself. Always leave a contingency fund of 10-15%.

RULES AND REGULATIONS

The Party Wall etc Act 1996 (England and Wales): If you are extending to or within 6m of a neighbour’s boundary, or are altering any part of a party wall structure then work will come under the Party Wall Act. You will need to instruct a surveyor to prepare a Party Wall Settlement and this is likely to cost around £700 plus VAT per agreement.

The Right of Light: The ‘right of light’ does not prevent your extension from reducing the amount of light into a neighbour’s windows. Their entitlement to light is only affected if the reduction in light makes the property less fit than it was for its purpose.

 Other Restrictions: If your property was owned by the council, church, Coal Board, a housing association or any other body, it may be subject to restrictive covenants. You may need consent, or at least to inform the beneficiary of the covenant before you can undertake work. This is also likely to be the case if your property is leasehold. If your proposed extension alters an existing right of way then you will need to negotiate with the beneficiaries.

WHERE TO FIND AN ARCHITECT

RIBA – The Royal Institute of British Architects. Tel: 020 7307 3700 www.architecture.com

RIAS – The Royal Incorporation of Architects in Scotland. Tel: 0131 229 7545 www.rias.org.uk

RSAW – The Royal Society of Architects in Wales. Tel: 029 2087 4753

RSUA – The Royal Society of Ulster Architects. Tel: 028 9032 3760 www.rsua.org.uk

RIAI – The Royal Institute of the Architects of Ireland. Tel: +353 (0)1 676 1703

WHERE TO FIND AN ARCHITECTURAL TECHNOLOGIST

CIAT – Chartered Institute of Architectural Technologists (CIAT), formerly British Institute of Architectural Technologists (BIAT). Tel: 020 7278 2206 www.ciat.org.uk

WHERE TO FIND A BUILDING SURVEYOR

RICS – Royal Institution of Chartered Surveyors. Tel: 0870 333 1600 www.rics.org.uk