In order to help you on the path to getting your barn conversion right, I have identified a number of factors to consider.
When identifying possible barn conversion sites check whether there are any particular planning restrictions on the site. For example, is it situated within a National Park, or an Area of Outstanding Natural Beauty? Or is the barn itself a Listed building? This will help you decide the most suitable site for your project.
When it comes to the plot, take a look at what services are evident and if there is adequate space for parking, a garden and potentially a sewage treatment plant.
Large trees surrounding the building could impact on the foundations, or they might have tree protection orders, so make sure to ask this before you start any design work.
When you first go to view a potential barn, take a good look around. Make a note of any cracks, which might denote structural issues, decay or invasive vegetation which are often an indication of weather ingress.
If you see any decay or infestation within the wooden structure, a timber survey is essential to ensure the barn can withstand any changes.
Similarly, if you see any evidence of wildlife, such as bats or owls, a specialist biodiversity survey will be required for planning applications, which will outline suitable mitigation proposals.
I would advise that you allow a budget of around £3,500 per m², but it is hard to estimate the total build costs for a barn conversion, because it very much depends on the nature of the existing building’s fabric and its condition. I suggest in addition you allow for a contingency of around 10% for the construction costs for unexpected items that become apparent during opening up works. Keep in mind that typically VAT is charged at 5% on conversions to dwellings, plus there will be consultant and statutory authorities fees to account for.
Converting a barn is generally more expensive than a new build or standard renovation, but it is far more sustainable to repurpose an existing building. Barns also offer unique character and are often an integral part of an area’s rural history.
For this type of build, you will need either full permission (with Listed Building Consent if your building is Listed), or prior approval under Class Q of Permitted Development (PD).
Class Q does not apply to properties that are listed or on protected land and it has very specific parameters that have to be met. So, you would be wise to read the legislation carefully and if necessary, appoint a planning consultant. One potential benefit of a full application is that planning policies are less prescriptive than PD rules, which allows for some interpretation by the case officer.
Structural surveys are often required when applying for permission for a conversion. They help to ascertain the condition of the barn and its aptness for alteration. This can enhance your planning application.
If you are applying for permission under Permitted Development a structural survey will be a prerequisite in demonstrating that the existing barn is suitable for conversion.
Most barns provide ideal habitats for protected fauna and flora. Most commonly nesting birds and bats. Biodiversity surveys are often required as part of any planning application.
Consideration of biodiversity within developments is becoming an increasingly important aspect of the construction process.
The timing of mitigation measures and construction works near a habitat may be impacted by the life cycle of the particular species. Works might have to be undertaken around breeding seasons in order to minimise disturbances. Plan ahead, as far as possible.
Typical mitigation measures include bat and bird boxes together with dedicated breeding and roost sites, allowing wildlife to breed and roost undisturbed.
You will have to comply with the current Building Regulations for any building work.
When insulating an existing building in order to prevent trapped condensation, take great care to choose a system that allows the building fabric to breathe, either through vapour permeability or using an appropriate air gap.
It’s highly likely that there will be limited mains services on the plot and as you have a blank canvas it is an ideal opportunity to explore heat pump options and the potential for a mechanical ventilation and heat recovery system (MVHR). Heat tends to accumulate in the higher points of the building, called the stack effect, and MVHR will draw in the warmed air trapped at ceiling level and reuse this to help warm the cooler air at lower levels.
Aim to keep the rustic characteristics of the property, as these are what will make your new home unique. Be careful when looking at adding an additional storey internally – most barns feature a steeply pitched roof which, although impressive, means there will be limited usable head height. Similarly, some structural timber beams could be at the wrong height to permit a mezzanine. Work with the existing layout as much as possible. Resist the urge to create too many new zones or partitions.
Another quirk that comes with a barn conversion, is that the typology tends to have very few windows. Planners are normally reluctant to allow more openings within the walls and roof, for fear that it could harm the existing character of the building – so make sure not to have too heavy a hand when it comes to glazing. Where possible, use existing openings or those that might have been infilled, to draw in natural light and make the most of any views.
You can view case study Barn conversions here.
If you are considering embarking on a barn conversion or renovating project and wish to speak to an architect in more detail or have further questions, please feel free to contact me.
Sections of this article originally appeared in the May 2025 issue of Build It magazine.