Building Regulations

Understanding permitted development

Planning permission and Building Regulations are two separate considerations when installing a log cabin or garden building. Planning permission relates to whether you are allowed to carry out the development, while Building Regulations are concerned with ensuring the building is constructed safely and meets the standards required for its intended use. Receiving planning permission—or building under permitted development rights—does not automatically mean that Building Regulations approval has also been granted. Keops

For many garden structures and log cabins with an internal floor area of less than 30m², Building Regulations may not apply, although the intended use and position of the building are important. A cabin being used as a dwelling may need to comply regardless of its size, while buildings attached to or positioned very close to the main house may be treated more like an extension and therefore need to meet the relevant residential standards. Mobile homes and transportable dwellings can be treated differently and may require a different approach to both Building Regulations and planning permission.

Boundary position is another important consideration. Where a building has external walls made from combustible materials and an internal floor area greater than 15m², the existing Keops guidance advises that it should generally be positioned at least 1,000mm from a third-party boundary to help reduce the risk of fire spread. Where this cannot be achieved, additional fire-resistant measures may be required and should be discussed with the relevant Building Control body before construction.

If your log cabin has an internal floor area greater than 30m², Building Regulations approval should generally be considered as part of the project. Every building and site is different, so we recommend discussing your plans with Building Control where there is any uncertainty. Keops can also help you consider elements such as structure, insulation, glazing, foundations and fire protection when developing your cabin specification.

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Areas to Consider

The 14 building regulations

Where Building Regulations approval is required, the proposed building may need to demonstrate how it satisfies a number of different areas of the regulations. Not every section will be equally relevant to every log cabin or garden building, but understanding them at an early stage can help ensure the design, construction and specification are appropriate. The existing Keops guidance covers the following 14 areas.

  • Part A – Structural StabilityCovers the strength and stability of the building, including its foundations and ability to withstand loads such as wind and snow. Structural calculations may sometimes be required.
  • Part B – Fire SafetyParticularly important where a log cabin is positioned close to a boundary or another building. Fire requirements can also become more significant for residential or commercial buildings.
  • Part C – Site Preparation and Resistance to MoistureCovers appropriate materials, workmanship, site preparation and measures designed to protect the building from moisture.
  • Part D – Toxic SubstancesConsiders the potential effects of toxic substances used within or around the construction of the building.
  • Part E – Resistance to SoundCovers sound insulation and may become more relevant depending on the intended use, layout and occupancy of the building.
  • Part F – VentilationEnsures suitable ventilation is provided, particularly where the cabin is designed for regular or extended use.
  • Part G – Sanitation, Hot Water Safety and Water EfficiencyMore likely to be relevant where a log cabin incorporates facilities such as a bathroom, WC, kitchen or hot water system.
  • Part H – Drainage and Waste DisposalImportant where drainage, wastewater or sanitary facilities form part of the project and should be designed using suitable approved methods.
  • Part J – Combustion Appliances and Fuel Storage SystemsMay apply where a cabin contains a stove, fireplace, boiler or another combustion appliance.
  • Part K – Protection from Falling, Collision and ImpactCovers areas such as stairs, changes in floor level and protection against falls. It is generally less significant for simple single-storey cabins without stairways.
  • Part L – Conservation of Fuel and PowerParticularly relevant for heated log cabins and garden rooms. The roof, floor, walls, windows and doors may need to achieve appropriate levels of thermal performance, making the insulation specification an important part of the design.
  • Part M – Access to and Use of BuildingsMay apply where accessible or disabled access is required, particularly for certain commercial, educational or public-facing buildings.
  • Part N – GlazingThe existing Keops guidance highlights the importance of safety glazing in doors, glazed side panels and low-level windows to reduce the risk of injury.
  • Part P – Electrical SafetyRelevant wherever electrical work is being installed. Electrical installations should be carried out to the appropriate standards by a suitably competent and registered electrician.