Design Masterclass: Extending a Cottage

ABOVE: This significant extension has merged well with the original, partly due to the fact that the whole cottage has benefitted from being re-thatched (it cost over £20,000). It houses a new master bedroom and was designed by Le Sage Associates (01778 344200)

The idea of the traditional cottage has an enduring appeal, but the reality of living in relatively small rooms, often with low ceilings, leads many owners to seek out more space. But how do you achieve this without detracting from the building’s original character? The key to successfully extending a traditional cottage must begin with an understanding of the origins of the type of dwelling itself, and the key elements that constitute ‘cottage’ architecture. For most, the term conjures up images of a small, simple dwelling, probably in a rural location, possibly thatched, with a large chimney, small-paned windows and a porch.

In design terms, however, it is much harder to define precisely a style that embraces cottage architecture across the whole of the British Isles. This is essentially because there is no one style, but more a series of regional styles, each as unique and varied as the land itself.

The cottage is the home in its most simple, vernacular form, built out of expediency from whatever was close to hand and cheap to acquire, using whatever local craft traditions had been handed down through the generations. Villages only a mile or so apart, therefore, often have utterly different vernacular building styles, depending on the underlying geology, tradition, ownership and even transport and trade links, whilst others 100 or more miles apart may be remarkably similar. 

ABOVE: A complementary addition The two storey extension to this Grade II listed cottage (on the right) complements the original, which was improved at the same time. Interestingly, the upper storeys of the two parts are not linked. Designed by Philip Proctor (01747 851881; philipproctor.co.uk)

The passage of time has also played its part in forming the character of these simple dwellings, as the vernacular evolved, and as homes were adapted through extension, improvement and possibly periods of neglect or even abandonment. Each new wave of building reflected its day, as new materials were introduced or became more accessible, as architectural fashions came and went, or as the fortune of the region, or the building’s occupants, ebbed and flowed.

This process of evolution continues to this day, with the extensions and improvements of the 21st century still changing and adding to their character. There are those who prefer the ‘honesty’ of extending traditional cottages using modern materials and contemporary forms to reflect the architecture of today, and in many ways this is the natural and logical progression of the ‘vernacular style’. Here, however, we focus purely on extending in ‘traditional’ style, which for the majority still holds the greatest appeal and is considered to be the most sympathetic.

Style

True cottage architecture is unrefined and pragmatic, with simple unfussy details, no particular symmetry, modest window and door openings, low eaves and obvious porches or door canopies. The style often appears to have evolved by accident rather than by design, with irregular form and mismatching rustic materials, all resulting in an individual, often picturesque charm. These are the essential elements that must inform the style of any successful traditional-style addition to a cottage, but it is much harder to get this right than it seems. The danger in attempting to create something that looks like it has evolved is that it ends up looking contrived, or twee. The Cottage Ornee style of 1730-1820 (SEE BELOW) drew together elements of traditional rustic cottage style from different regions and periods and pieced them together, creating a hybrid ‘cottage style’, often seen on gatehouses. Details became more decorative (hence Ornee, meaning ‘adorned’ in French) including leaded lights, occasionally Gothic arched door or window openings, thatched roofs and external joinery, such as bargeboards with filigree fretwork. The best approach to extending in traditional style is to photograph similar local buildings and to try and interpret their language, noting materials, details and so on. 

Differential Movement

Traditional buildings tend to have been built with little or no foundations as we understand them today. In poor ground conditions it is usual for period buildings to move over the course of the year, as the soil expands and contracts. Traditional buildings generally have sufficient flexibility to sustain a degree of movement. New extensions will, however, be constructed with deep concrete foundations and a rigid structure. Independently, both old and new structures can deal with the ground conditions in their own way. However, if they are joined together rigidly, any differential movement can literally rip them apart, at best leading to leaks and damp problems, and at worst causing severe structural damage. It is therefore essential to allow movement, with expansion joints at all junctions between old and new, including the floor slab, floor finishes, walls and roof. Sliding anchor ties and movement ties with a debonding sleeve are available that can accommodate movement.

Designers' Views

"In many ways, it is more difficult to extend than design a new house"

- John Greene, founder of Border Oak shares his views

The trick is to know when to contrast and when to complement. It is important to consider your aims and restrictions:

• From a planning and design perspective the extension should normally be subservient or ‘visually distinctive’ to the original building – which often means lower, smaller, simpler and with different materials – to demonstrate an evolution of the building and to avoid conflict with the original.

• We often propose a separate, but adjacent, independent structure — not relying on the host building for structural support. A simple glazed link is a good device to employ.

• Ideally, the span of the extension should be no greater than the cottage — to complement traditional proportions.

• A drop, or break, in ridge line is a forgiving and attractive measure.

• Contemporary details work well, but avoid ‘visual dominance’. A deliberately contemporary extension is an honest way to add space but it’s usually best not to overwhelm the original.

• Vernacular proportions, scale, materials and details reinterpreted in a modern way can help bridge the gap between historic and new. Your local palette will be obvious by looking around your area.

• The simple impact of a large contemporary room designed around modern family life can totally transform and reinvigorate a period cottage. All this means a good designer with experience of similar projects is crucial.

John Greene is the Founder of Border Oak Design & Construction (01568 708752; borderoak.com). He has designed several extensions to period cottages, as well as many new builds.

"Don’t Copy the Original"

- Peter King, architect and principal of Oxfordshire based practice Carden King

Do

Add character: Extensions that just copy the original structure are rarely successful — they are too ingratiating. A new extension needs to have its own character, though it should still be in sympathy with the original building either in form or some aspect of its materials treatment.

Keep visual separation: Planners like to be able to clearly distinguish the new from the original. When extending use ‘setbacks’ in wall lines where the new work starts and/or use contrasting materials to give visual separation.

Vary windows and doors: In extensions use window and door designs that are different from those of the original building. This aids ‘separation’ as mentioned above, and allows you to add modern thermally efficient technology in the extended part.

Use lime mortars: If altering or extending original walls, use lime-based mortars rather than cement-based mortars. Not only does lime in the mix allow movement and moisture migration but its colour will better match that of the original wall. Examine original mortars carefully and try to obtain the same colour sand for the mortar mix.

Don't

Overextend: Never overextend a property, even if you really want the additional space. An overlarge extension will blight and disrespect the original building. Small is beautiful.

Remove fireplaces: Historic buildings have strong chimney stack signatures. Don’t remove these unless the reasons for doing so are compelling. Consider adding a new fireplace/stack elsewhere if obliged to remove one.

Replace windows: Never replace original windows with new ones of a different design or material. What is original should be replaced exactly like for like.

Oversize windows: Where an extension has orthodox windows, don’t oversize these. This goes for dormers and rooflights also. Within reason, the smaller the better.

Fake it: Don’t use substitute materials and never use details like false chimney stacks or double-glazed windows with fake glazing bars. Anything pretending to be something else should not be used.

Be over-formal: Don’t use architectural formality inappropriately. For a manor house or Georgian townhouse formality is appropriate. It is not appropriate in an old cottage or barn.

Peter King is an architect and principal of Oxfordshire-based Carden King Partnership and has designed several extension schemes for period cottages. Carden King: 01367 253330 cardenking.co.uk

Further Reading: 

• Extending a Cottage - Design Solutions
• Converting Four Period Cottages into One Home 
• Extending and Renovating An Old Cottage