Will my oak framed garage/annexe need planning permission?
When you’re planning an oak framed garage or annexe on your property in Hampshire or the New Forest, one of the first questions is: do I need planning permission, or can I build it under permitted development rights (PD)?
The answer depends on several factors: the purpose of the building, its size, height, and position, and whether your property lies in a protected area such as the New Forest National Park. This guide explains everything you need to know.
What counts as an outbuilding under permitted development?
In planning law, an oak framed garage or annexe is normally classed as an outbuilding. Outbuildings include sheds, garages, greenhouses, garden rooms, and similar structures. Under national rules (The Town and Country Planning (General Permitted Development) Order 2015), you can build certain outbuildings without needing full planning permission—so long as you stay within strict limits.
However, if the structure is intended as a separate home or fully self-contained annexe (with a kitchen and bathroom for independent living), it will usually require planning permission because it goes beyond what’s “incidental to the enjoyment of the dwelling.”
National permitted development rules for garages and annexes
Your oak framed garage/annexe may fall under permitted development if it meets the following rules:
- Purpose: It must be incidental to the main house (storage, workshop, gym, office, studio, or non-self-contained annexe).
- Height:
- Maximum 4m for a dual-pitched roof.
- Maximum 3m for other roof types.
- If within 2m of a boundary, no part of the building can exceed 2.5m in height.
- Eaves must not exceed 2.5m in height.
- Storeys: Only single storey buildings are allowed.
- Position: It cannot sit forward of the principal elevation (front wall) of the house.
- Footprint / coverage: Combined outbuildings must not cover more than 50% of the land around the “original house” (excluding the footprint of the house itself).
- Use of land: The land must form part of the residential curtilage (e.g., garden or yard) of the house.
If the outbuilding fails any of these conditions, you’ll need planning permission.
Special rules for designated land in the New Forest
Properties in the New Forest National Park or in Conservation Areas face extra restrictions. These areas are considered “designated land,” and the following additional rules apply:
- Side of house: Outbuildings to the side of the house usually require planning permission.
- 20m rule: If an outbuilding is more than 20m from the original house, its footprint under PD is limited to 10m².
- Article 4 Directions: Some parts of the New Forest have Article 4 Directions that remove permitted development rights altogether. In these areas, even small outbuildings may require planning permission.
- Design & materials: The authority may require designs that are sympathetic to local character, which is highly relevant if you’re building an oak framed structure.
If your property is within the National Park or Conservation Area, it is always worth confirming with the New Forest National Park Authority (NFNPA) before building.
Oak framed annexes: a special case
An oak framed annexe designed for relatives, guests, or as additional living space is a grey area. If it is incidental (for example, a guest bedroom without a kitchen), it may qualify under PD. But if it is intended as a separate dwelling unit, it will almost certainly need full planning permission.
For certainty, homeowners often apply for a Lawful Development Certificate to prove the structure falls under permitted development. This avoids problems when selling your property later.
Building Regulations still apply
Even if your oak framed garage or annexe does not need planning permission, it may still need to comply with Building Regulations. Regulations cover structural safety, insulation, fire protection, drainage, and electrics. Garages usually have lighter requirements, but annexes or habitable rooms must comply fully.
Do I need planning permission?
- Purpose: Is it incidental (storage, workshop, guest room without kitchen)?
- Yes → continue.
- No (self-contained annexe) → planning permission required.
- Designated land: Are you in the New Forest National Park, Conservation Area, or Article 4 area?
- Yes → stricter rules apply. Planning permission often required.
- No → continue.
- Size & height: Does it stay within national limits (single storey, 4m max height, 2.5m within 2m of boundary, eaves ≤ 2.5m)?
- Yes → continue.
- No → planning permission required.
- Coverage: Does the total of all outbuildings cover less than 50% of the curtilage (excluding house footprint)?
- Yes → permitted development.
- No → planning permission required.
Key takeaways for Hampshire & New Forest homeowners
- A simple oak framed garage may fall under permitted development if it meets national size, height, and location limits.
- An oak framed annexe used for independent living will almost always need planning permission.
- In the New Forest National Park, rules are stricter. Outbuildings larger than 10m² or positioned at the side of the house will often require permission.
- Building Regulations apply regardless of planning status.
To be absolutely sure, call us today to discuss.
