How to extend your period property

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Roger Hunt Period property expert

Scale, style and design – find out what to consider when planning an extension to your home to avoid compromising the building’s existing character and charm.

The first rule when extending a period property is: don’t try to turn a cottage into a castle. Extensions that are out of scale and context mean that you risk losing the character and history which initially attracted you to the building, plus they’re likely to make the internal proportions of the property feel unbalanced.

Many old properties don’t suit modern lifestyles, so changes are inevitable and part of a building’s natural evolution. Extending successfully relies on understanding how the internal spaces work, a respect for the age and history of the property, achieving appropriate scale internally and externally, as well as a careful choice of materials.

Design considerations
Plan the extension so that it doesn’t detract from the proportions or key features of the existing building and try to maintain the ‘rhythm’ of the architecture. Above all, do ensure that it enhances rather than detracts from the look of the property. Think about this particularly carefully if it’s part of a terrace – anything you do to the front or the back of the house could spoil the appearance of the entire row.

This does not mean it has to replicate the original architectural style or materials. It’s worth remembering that many period properties are beautiful because of later additions from different eras. Rather than poor pastiche, good modern design – which is honest to the style of architecture today – frequently works better and creates exciting living spaces.

Think carefully before adding a conservatory. These were a Victorian invention and were used as an addition to larger houses, so they can look wrong on buildings of earlier eras and were never found on smaller homes. While there are some good modern reproductions, remember that simple is often best – originally the frames were cast-iron or timber and this is reflected in the fine quality of the detailing. In comparison, uPVC versions can be cumbersome.

Reversibility is another issue to think about. Try to design an extension so that it can be removed in the future with minimum damage to the historic fabric of the building. For example, make it an independent structure with the minimum number of fixings to the old building. The same considerations apply when deciding how to access the new space from the old. If possible, avoid knocking holes in original walls and instead use and incorporate existing window or door openings.

Bear in mind that traditional materials behave differently to contemporary products, such as cement – when used inappropriately, they can cause damp and other issues. In addition, due to differential settlement, problems can occur when a new extension with deep foundations is attached to an old building with shallow foundations, so ensure that the junction between the two allows for movement.

Modern building regulations may prevent a copy of the construction methods used in the original structure. Even so, it is still possible to use lime mortars, plasters and renders and materials like hemp lime or clay blocks for building, which have the added benefit of being eco-friendly.

Rules and regulations
As well as planning permission and building regulations, a key consideration is whether your property is listed or lies within a conservation area. If you plan to alter or extend a listed building in any way that affects its character, inside or out, you must apply for listed building consent.

A good starting point for information is the government’s Planning Portal (planningportal.gov.uk). It’s also worth speaking to the conservation officer at your local authority planning department and being honest with them about the extension you’re contemplating, as the rules on extending in a conservation area will vary from area to area. They can offer good advice and may point you in the direction of the right tradespeople and professionals who can help with the build.

Getting advice
Before undertaking any work, it’s worth doing some research to understand the building’s history and the materials and techniques used in its construction. The Society for the Protection of Ancient Buildings (020 7377 1644, spab.org.uk) offers publications, runs courses and has a free advice line, while The Georgian Group (087 1750 2936; georgiangroup.org.uk) and The Victorian Society (020 8994 1019, victoriansociety.org.uk) have useful guides.

Roger Hunt is co-author of The Old House Handbook.

FEATURE ROGER HUNT PHOTOGRAPHS ALAN WILLIAMS
Featured in the November 2011 issue of Real Homes