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Barn Conversion Design Guide

converted barn with glazed side doors
(Image credit: Simon Maxwell)

When it comes to barn conversion design, if there is only one rule that you follow, it is to be ‘true to the building’. Ignore that rule, and you will lose the wonderful character and form that a barn conversion offers.

Bear this rule in mind across every area of the design, from walls and windows to doors and internal layout, and you’ll not only maintain the integrity of the form, but also please the local authority planners in the process.

Barn Walls

Existing exterior walls, be they in stone, brick or timber, should be repaired on a like-for-like basis. To achieve a seamless blend between original and repairs/alterations, it may be possible to repoint the whole wall, using lime mortar to retain breathability, and ensuring that removing the original mortar is kept to a minimum.

New partition walls could be built in matching brick or stone and left exposed, but an alternative, and an increasingly popular design ethos, is to use contrasting materials for all new structures and to create a clear distinction between old and new.

This stone barn conversion was carefully restored by its owners to retain its rural charm

This stone barn conversion was carefully restored by its owners to retain its rural charm (Image credit: Nigel Rigden)

Brick or stone walls will invariably be of solid construction (no cavity), and so the addition of insulation necessary to meet Building Regulations Part L. This will need to be to the internal face of the external walls to maintain the exterior appearance.

Leaving some sections of the brick or stone fabric exposed internally can be a desirable design feature; however, because of insulation requirements, it is usually easier to achieve this with internal partition walls — although it may be possible to clad some parts of the inner face of the exterior walls with brick or stone, forming an insulated cavity wall which can be left as a feature.

Timber frame barns present less of a problem for converters, especially in terms of insulating the building envelope. The existing cladding – usually timber – can often be removed, and a layer of insulation added in between and over the frame, plus a breathable damp-proof membrane. Where possible, salvage and reuse as much of the original cladding, and make up balance using like-for-like materials.

Where the original sole plate and lower section of the wall studs are badly damaged by rot or infestation, it may be possible to cut back the damaged timber and introduce a new sole plate at a slightly higher level, and to raise the plinth wall.

Repairing and Altering a Barn Roof

The roof is the predominant feature of a barn. In most cases it will be necessary to remove the existing roof covering to allow for roof repairs or alterations, and the addition of insulation and membrane to improve weatherproofing and airtightness.

Insulation can be applied between and beneath the rafters, but where the rafters are made from interesting timbers, and considered worth leaving exposed as an internal feature, it will be necessary to insulate between and over them. This will raise the height of the roof by approximately 100mm.

Part of the charm of a barn conversion can be the irregularity of the roof shape where the original timbers may have bowed, twisted and warped over time. Although evening out the roof will help the roof covering sit flush and weathertight, a completely symmetrical new roof, laid with replacement tiles, can lack character. With care, the roof can be repaired but the undulations carefully maintained.

Introducing More Light with Glazing

Dormer windows are not usually appropriate, so any new window openings in the roof will be rooflights, and in most instances metal conservation-style rooflights which sit flush with the line of the roof. Too many rooflights usually looks wrong, and it is best to keep them on the less important elevations.

It may also be possible to introduce a larger area of glazing on minor, less prominent elevations, using a bespoke rooflight system, or by glazing a section of the roof between the existing rafters.

converted barn with glazed side doors

Glazed sliding doors and a glazed link work to flood this converted barn with natural light (Image credit: Simon Maxwell)

Vernacular roofing, such as limestone or sandstone tiles, local slate, thatch or local handmade clay tiles, is often an intrinsic part of the character of a barn. It is, therefore, worth salvaging as much as possible of this material and sourcing replacements to make up for any shortfall.

Where new and original roof coverings are mixed together, the original material can be used on the main ‘public’ elevations and the new material on less prominent, minor roof planes, or alternatively on outbuildings. Like-for-like replacement will often be a requirement on a listed building, but for less sensitive situations planners may be more flexible, especially where the material is very expensive or unavailable.

Barn Windows, Doors and Openings

On the main elevations, window and door openings will often be restricted to those that already exist. On secondary elevations some additional window openings and doorways may be allowed.

If a new opening is to be inserted, sympathetic proportions and detailing should be used, following existing patterns on the building, or other similar farm buildings in the area. In some instances, subject to careful design, new openings could be contemporary in style, though different local planning authorities will take different views on this.

For instance, replacing some sections of horizontal timber boarding with clear or translucent Perspex, or glazing part of a gable elevation, in between the timber studs.

Barn Joinery

Windows and doors need to be simple, robust and functional in style. Setting the windows back into the walls also helps to maintain the shadow lines of the original openings and limits reflections.

If there are any original windows left intact, then it is worth considering salvaging and repairing these, or at least using them as a template for replacements. If there are no surviving windows, look at local farm buildings in the vicinity for clues as to the tradition. Off-the-shelf windows are unlikely to be suitable for size or design.

Narrow ventilation slits are common in agricultural buildings in some areas, and these can be glazed with a fixed double-glazed unit. Other openings can also be fitted with fixed glazed units, as these may read as unaltered open voids.

A pairing of a dramatic cantilevered extension and stone barn brings a vibrant feel to Paul and Elaine Haffey’s new home

A pairing of a dramatic cantilevered extension and stone barn brings a vibrant feel to Paul and Elaine Haffey’s new home (Image credit: Chris Hill)

Frameless glazing is an option that can be used to fill even the largest opening and – when set well back into the opening – can be unobtrusive.

Barn doors are usually utilitarian, constructed from vertical planks of timber. Proportions are usually sturdy and the outer frame section wide and solid. New doors should follow this pattern with the same finish used for doors and windows. Door furniture and other ironmongery items such as hinges should also be utilitarian.

Extending a Conversion

Large additions to a barn are unlikely to be acceptable to the planners in most instances, but smaller subordinate additions may be, especially to the minor elevations.

A good justification for such an addition is that it will house facilities like a cloakroom, utility room, boiler room or other ancillary rooms, and thereby prevent too much subdivision of the main space, avoiding the subsequent loss of character this would entail.

  • Lean-to-style additions with a simple monopitch roof, designed to look like an existing addition to the barn, can be a good option
  • Extensions that link barns and other outbuildings may also be acceptable if designed appropriately: infilling is unlikely to be acceptable, but as with a listed building, a frameless glass link would be difficult for planners to object to
  • Additions such as porches, conventional conservatories or attached garages are not likely to be appropriate. A modest extension using green oak framing may be more acceptable. It may also be easier to gain consent for an extension at a later date, once the initial conversion has been completed
  • Garaging is best provided through the conversion of outbuildings, or the construction of new, sympathetically designed outbuildings. These could be styled to look like shelters, open cart sheds, stables or other agricultural buildings

Barn Conversion Interior Design

When it comes to internal layout, the key considerations are:

  • the use of natural light, which is often relatively limited
  • retaining the sense of volume and openness of the original space
  • and, if it is attractive, making use of the exposed open roof structure as a feature

Layout options may also be limited by the position of existing internal partition walls, particularly if they are structural, or the position of posts and beams. If the building is protected, sometimes little or no alteration of the original fabric is allowed.

Kitchen of A Converted 300-Year-Old Barn

Lorna and Chris Harrison’s design brief was for a modern home full of contemporary design ideas, which worked sympathetically with the barn’s beautiful rural location (Image credit: Jeremy Phillips)

The flow between spaces is also an important consideration, with the room plan determined to a large extent by the separation of ‘private’ and ‘public’ space and the key relationships between different functions such as kitchen and dining, bedrooms and bathrooms.

Barns are usually long and relatively narrow, and so a central hallway is often the most space efficient option to provide access and circulation. It is also the ideal place to have a space that is open floor to the ridge, at least in part, so that the sense of volume – the most appealing characteristic of a barn – is apparent immediately upon entering the building.

The first floor will typically need to be linked across the open central hallway — although some design solutions have two staircases or a split staircase, with the bedroom accommodation divided into two, the master bedroom arrangement to one side, and family or guest bedrooms to the other, accessed from a galleried landing.

A key consideration here is to avoid cutting across the main glazed barn door opening, so a galleried ‘bridge’ landing, with a void either side, is a good solution.

In some instances, an upside-down configuration can be the best solution, with an open plan living, kitchen and dining space on the top floor, underneath an open vaulted roof structure, and the bedrooms and bathrooms on the ground floor where there is more flexibility for layout options, and fewer access problems created by restricted headroom. Such living spaces are often open plan and have a gallery overlooking the stairwell.

Open plan room arrangements for the living spaces help maximise the use of borrowed light, as will splaying window and door reveals and rounding off the arises (the external corners of walls). A light-reflecting colour scheme will also help.

Adding Floors

Top tip

Learn more about converting a barn with our beginner’s how to guide. It covers everything from finding a barn, to planning permission and design.

Options to divide the space horizontally to create additional storeys will depend on the height of the building. Barns often combine sections with single, two or even three storeys to take best advantage of the volume that is available.

Use of this space may be restricted by the slope of the roof, tie beams or collars on roof trusses. In some instances, it may be acceptable to alter the roof trusses to create access between first floor rooms, but if this is not possible it may be necessary to design sunken stairwells.

It is usually necessary to excavate the existing floor in order to lay a new floor structure, and in the process it may be possible to create additional volume by excavating to a lower level.

Subject to calculations to assess loadings, it may be possible to use existing brick or stone walls to help support new floor structures, but this may necessitate underpinning. In this case a completely independent structure, such as an internal timber or steel frame, supported by piers and columns, might be preferable.

Essential Barn Conversion Design Tips:

  • Preserve the building’s original form and character
  • Apply a light touch
  • Reuse materials wherever possible
  • Use like-for-like materials and traditional techniques
  • Minimise the subdivision of internal space to preserve openness
  • Keep the roof structure open and visible
  • Use existing openings and minimise the formation of new ones
  • Avoid ‘domestic-style’ windows and ‘off-the-peg’ joinery
  • Minimise the addition of rooflights and use conservation models
  • Avoid creating a suburban garden — keep appropriate boundary treatments
  • Keep any new additions sensitive in scale and style
  • Avoid infilling — keep any links transparent using frameless glazing
  • Avoid inserting floors that cut across window openings
  • Keep flues and soil vent pipes hidden or on minor elevations