If you plan to put up a small, detached building like a garden shed, garden room, garden office, annexe or summerhouse (all classed as outbuildings), building regulations generally won’t apply if the building has a floor area under 15 square metres and does not include any sleeping accommodation.
For buildings with a floor area between 15 and 30 square metres, building regulations approval is usually not needed - as long as the building does not include sleeping accommodation and either:
Read more about the building regulations that apply to outbuildings.
Don't forget to check the permitted development rights for outbuildings.
Once submitted, your planning application first goes through a validation process. After its validated, the formal decision period is 8 weeks. However, in some cases, especially for more complex proposals or if further information is needed, your local authority may request an extension of time.
Understand more about the decision-making process on Planning Portal
Foundations are required to carry and distribute the load of the building safely. Therefore, all buildings should have adequate foundations. The factors that need to be considered when designing a foundation are:
It is advisable to contact a structural engineer or speak to a building control body about plans for new foundations.
Read more about foundations for extensions
Yes, but you will need to obtain planning permission. Converting a detached garage into a self-contained living space, such as annexe, studio flat, or retail unit, represents a material change of use, particularly if it will function independently from the main house. This is because the garage would no longer be used in connection with the main dwelling and would effectively become a separate residential unit.
A roof window (or skylight) is fitted flush within the slope of a roof, while a dormer projects outward, creating additional headroom and floor space.
Both can be installed under permitted development but must meet specific size and position limits to qualify.
Also consider building regulations for a new dormer, find out more on Planning Portal
If you carry out development without the necessary planning permission, and it doesn’t fall within permitted development rights, you may be in breach of the planning rules. In such cases, you will usually need to submit a retrospective planning application to seek approval for the work already completed or started. However, there is no guarantee that permission will be granted.
Learn more about planning breaches on Planning Portal