The Best Windows for a Barn Conversion

Before choosing a system, list the openings you actually have and what each one has to do. Barns usually break down into a small number of categories, and each one wants a different answer.

Aluminium is usually the right answer on a barn conversion, and for structural rather than stylistic reasons. Barn openings tend to be large, the glass is heavy, and aluminium holds slim sections across wide spans without the frame depth other materials need. On a cart door screen or a gable apex, that is the difference between a view and a grid.

That said, aluminium is not automatically right everywhere on the building. Where a barn has been extended with smaller domestic windows, or where a planning officer has asked for a traditional appearance on a road-facing elevation, a timber-look system with woodgrain detailing can be the more sympathetic choice. Mixing the two across a single project is common and entirely defensible: aluminium on the large interventions, timber-look on the small traditional openings.

• Large openings, gable screens, sliding doors — aluminium
• Small original openings on a sensitive elevation — timber-look, or slim aluminium in a heritage profile
• Internal division of a barn's open volume — steel-look internal glazing, which keeps the space readable rather than cutting it into rooms

In a barn the glazing is usually doing two jobs at once: bringing daylight into a building that was never designed for it, and framing whatever the barn happens to look at. Both push in the same direction — fewer, larger panes with less frame between them.

• Ask for interlock and frame sightlines in millimetres rather than accepting the word slimline; the meeting line between two sliding panels is the one you will look at every day
• Consider low-iron glass where a large screen faces a view, because standard float glass carries a faint green cast that becomes visible over big areas
• Specify solar control glass on south and west-facing screens. A barn's thermal mass helps, but a fully glazed cart door opening facing the afternoon sun will overheat without it
• Where the barn is exposed, discuss drainage detailing and gasket specification rather than assuming a standard domestic build-up is enough

Dark frames sit better against weathered stone and oak than pale ones. Anthracite grey and matt black are the two most specified finishes on our barn projects, with bronze tones working particularly well where the barn has exposed timber or a copper or corten element. White and light greys tend to look institutional against natural materials and draw the eye to the frame rather than the building.

Consider the inside separately. A dual-colour finish — dark outside, a softer grey or off-white inside — is often the right call in a converted barn where the interior is plastered and bright, and costs less than most people assume.

Barn conversions almost always require planning permission, and in the Lake District National Park or a conservation area the treatment of openings is one of the things most closely examined. We are not planning consultants and would not pretend to be, but we work alongside architects and agents on these projects regularly and know which glazing questions tend to come up.

• Whether new openings are proposed, and how many, is usually scrutinised more closely than the specification of the frames themselves
• Frame colour and how deeply glazing is recessed are often conditioned, so it is worth agreeing them before ordering
• Rooflights are commonly required to be conservation-style and flush with the roof pitch
• Building Regulations apply to the conversion as a whole, including thermal performance, safety glass and means of escape

On a barn conversion near Brampton, Carlisle, the principal decision was a 5600mm opening on the rear elevation. Rather than subdividing it, it was glazed as a single slimline sliding run in three panes, so the view carries across the whole opening and the original proportion of the opening is still legible from outside.

Where a barn's gable is being opened up, the apex screen is usually the more demanding item, both in design and installation, and is covered in our gable and apex glazing guide.