Building Regulations and Planning Permissions

Building Regulations for National Parks

Great Britain’s 15 national parks are legally protected areas, set apart to conserve and enhance the areas’ natural beauty, wildlife, and cultural heritage. The first national park to be created in Great Britain was the Peak District National Park in 1951; today, vast swathes of the country are protected as picturesque national parks. From Snowdonia to Exmoor, and the Brecon Beacons to the New Forest, diverse national parkland covers 9.3% of England, 19.9% of Wales, and 7.2% of Scotland. Together, these national parks attract millions of visitors each year, with many falling in love with the scenery and choosing to make a life in a national park.

In contrast with national parks overseas, a distinguishing feature of British national parks is that most are living, breathing parts of the human landscape. People have their homes in these parks and along with farming, this presence forms part of the parks’ intangible cultural heritage.

National Parks and Building Regulations

With conservation preferred to new building work, Great Britain’s national parks are home to large numbers of listed buildings – the Lake District National Park alone boasts more than 1,750 such properties – with many more structures that are otherwise protected.

In England, the rules and regulations concerning works on listed properties are set out in Approved Document L1B which covers the conservation of fuel and power in existing dwellings. Compliance with this regulation is needed for works such as window replacements, re-roofing, and rendering.

For those with homes in Scotland’s two national parks, Loch Lomond and the Trossachs, and the Cairngorms, the equivalent to Document L1B may be found in Section 6 (Energy) of the Scottish Building Standards. Don’t let the differences in English and Scottish planning laws concern you – our regional division covering the Midlands, North of England, Scotland, and Wales are experienced in working to Scottish Government norms and are on hand to assist throughout the process.

Regulations in Wales, meanwhile, have only been a devolved matter since 2014. As such, they have diverged little from their English counterparts; the equivalent Welsh document is still called Approved Document L1.

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Repairs and Replacements

Each national park is characterised by its own vernacular architecture, from the Pembrokeshire Coast’s lime-washed cottages to the South Downs’ brick and flint homes and Dartmoor’s longhouses. Windows too are an architectural feature influenced by local customs and resources.

Approved Document L1B acknowledges that as windows form a key part of a historic building’s fabric, it is often impossible to replace listed and other protected structures’ windows without falling foul of planning rules. Nevertheless, in most cases there will never be an obligation to replace existing windows with L1B-compliant windows; the only time that a replacement will be mandated is when a building’s use is changed.

Approved Document L1B does not apply to repairs. Damaged panes, glazing bars and sills on non-compliant windows may be freely fixed, and mending is in fact preferred in most circumstances to outright replacement of a unit. Salvageable elements of damaged windows – particularly panes of glass – should always be reused. During the 20th century, glass manufacturing made significant technological advances, and since the 1960s, float glass – also known as annealed glass – has become the dominant form of domestic glazing.

Though of a higher quality than the glasses it replaced, float glass lacks certain charming characteristics inherent to older glasses such as crown glass, whose distinctive sparkle gives it an attractive and distinctive appearance. The main disadvantage of float glass concerns safety; when broken, float glass breaks into dangerous shards.

building regulations for glass box extensions in national parks

Repairs and Replacement

As an innovative business at the vanguard of British architectural glazing, IQ® Glass prides itself in providing products that are both beautiful and safe. For this reason, our standard glass is toughened glass. Toughened glass is five times stronger than float glass; on the occasions that it breaks, float glass will shatter into small, round, non-dangerous bits of glass – much like a car window. For this reason, toughened glass is alternatively known as safety glass.

To make toughened glass safer still, IQ® Glass also offers laminated glass units, which are bound by interlayers that prevent broken panes from dispersing. Toughened and toughened-laminated units are looked upon favourably by planners, who recognise and value the benefits of a safe home. The team at IQ can advise on specifications and asses where laminated glass is needed on a project by project basis.

Continuing with the preservation of traditional architectural aesthetics, many modern-style double glazed window systems are discouraged in national parks’ historic buildings; secondary glazing is preferred. Double glazing is further perceived as having the ‘disadvantage’ of requiring larger window profiles to support its thicker glass, making it harder to maintain heritage styles and to win approval from planners.

Today, however, double glazed panes need not be contained by the chunky frames typical of PVC units – nor do good frames need to be PVC. IQ Glass offers some of the slimmest premium aluminium profiles available on the market, including for heritage systems. Our Sieger® Legacy windows, inspired by the steel designs of the first half of the 20th century, boast sightlines of just 58mm.

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Repairs and Replacements

IQ Glass also offers other heritage-friendly options with modern twists. Our Mondrian® range of steel-framed slimline glazing incorporates traditional frame materials with contemporary minimalist design to offer 54mm sightlines. Mondrian® products were used to great effect in the renovation of Ashford Mill, a listed property in the Peak District National Park.

There are times, however, when an existing window is beyond repair. Under these circumstances, a replacement window will not only need to be L1B-compliant but will also be expected to be an exact replica of the window being replaced. Reproduction windows must therefore replicate the same materials and opening method as the original window.

Wherever possible, replacement windows for properties in English national parks must furthermore comply with the following other building regulations:

  • Approved Document B (means of escape)
  • Approved Document F (ventilation)
  • Approved Document J (air supply to heat-producing appliances)
  • Approved Document N (safety glazing)

If glazing is not being replaced and only alterations are made to existing windows, this must be carried out by FENSA-recognised contractors.

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New builds and Additions to Existing Builds

On certain occasions, new window openings are allowed to be created in the walls of national parks’ historic buildings. These new windows must be in keeping with the style of a property's existing windows, and modern styles are generally considered inappropriate.

Frameless windows provide another option for homeowners. Invisio®, the state-of-the-art frameless effect structural glazing system designed in house by IQ Glass, is popular with planners dealing with historic buildings and is regularly chosen by architects adding glass links to listed buildings. Frameless structural glazing can also be used for windows and doors and is perfect for converting partially exposed parts of buildings, such as stable entrances or arcades into new rooms, without interfering with the open character of these features. IQ Glass’ work on the Blenheim Palace estate (a UNESCO World Heritage site) may provide inspiration for homeowners of historic properties in national parks.

Although national parks exist to preserve specific environments, a balance must be struck between keeping them mothballed as time capsules and making them attractive, vibrant communities to live and work in.

Rules on permitted development – that is, allowing for modest extensions to be built without planning permission – apply to unlisted properties. Contemporary designs are allowed for such projects, so long as they are unobtrusive to their surrounding environment. Particularly welcome are designs that incorporate traditional local materials and building techniques.

An alternative to using traditional materials is to build fully glazed extensions. Such designs are discreet and have a minimal impact on their surroundings and are thus a popular option for extensions in national parks.

planning permission for luxury new build home in a national park

Planning Governance in National Parks

Each national park is administered by its own national park authority. Within the territory of a national park, district or unitary councils are superseded by the park authority as the local planning authority (LPA). As planning applications are made to LPAs, it is the park authorities that decide on which developments are permissible within park boundaries. LPAs also deal with listed building consent applications, which are required for all alterations to listed structures. Different LPAs will always have slightly diverging interpretations of regulations, and our teams at our five regional offices around the UK are highly experienced in working with planners across the UK and beyond.

Whilst planning permission and listed building consent lie with park authorities, it is worth noting that building regulations approval remains the responsibility of local district or unitary councils.

Inspired to combine modernity with tradition on your national park project? Then contact the team today, or visit us at our extensive showroom in Amersham, Buckinghamshire to see our comprehensive range of glazing solutions first hand.

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Further Reading

The following technical articles might also be useful if you are designing or specifying glazing for an extension or renovation project.

Thermal Performance in Modern House Design

Scottish Building Regulations Guide

Building Regulations Part L1 | Architectural Glazing to New Build Dwellings

Building Regulations Part L1 | Architectural Glazing to Existing Dwellings

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