Some building types and extensions are exempt and don't need formal approval or an application to be submitted within the building regulations:
Garages and carports
The construction of a non-combustible detached garage or attached carport (open on at least two sides) with an internal floor area less than 30m² wouldn't normally require building regulations approval.
Construction of a small detached building, such as a garden shed or summerhouse, won't normally require building regulations if the floor area of the building is less than 15m². If floor area is between 15 and 30m² you won't normally require building regulations, providing that the building is either at least 1m from the boundary or is built of substantially non-combustible material.
Construction of a porch, built at ground level, which is thermally separated from the house and has an internal floor area less than 30m² is normally exempt from the need to make an application, provided that the glazing and any fixed electrical installation complies with the requirements of the building regulations.
Work on the roof
If you want to carry out repairs, or recover a pitched or flat roof of an area that is less than 25% of that part of the roof, you won't normally need to submit a building regulation application.
If you want to repair or replace an existing drainpipe, manhole or associated fitting, building regulations approval isn't normally needed if the replacement is like for like.
Windows and doors (as opposed to new replacement doors and windows)
If you want to replace broken, fogged double glazing units, rotten sashes or rotten sections of the main frame members, building regulations won't apply.
A conservatory built at ground level and less than 30m² in internal floor area is exempt, provided that it is thermally separated from the property and that the glazing and any fixed electrical installations comply with building regulations requirements.