Permitted Development & Planning

The planning system in the UK is challenging to navigate and many complain about it, but it is this very challenge and risk which creates opportunity and a potential financial uplift. Smaller-scale developments subject to Permitted Development are much less challenging in terms of planning and they give a higher risk-reward return. Without specialist knowledge and experience, the system is risky. The key is to always discuss your options with a qualified and experienced planning consultant before any exchange of contracts. I do this myself before I exchange on any property. If your property of interest is in an area that is unfamiliar to you, choose a planning consultant with local area experience. You can find a suitable planner by looking at recent planning application history on your local planning explorer, which will give you a view of who the main players are in terms of planning experience in any given area.


Permitted Development (PD) rights are a type of general planning permission granted by Parliament; effectively, they are planning permissions granted by statute. PD rights allow you to bypass the submission of a formal planning application for certain alterations and extensions, but associated larger external physical development may still require planning permission. The rights are subject to ‘prior approval’, requiring consent of the local authority regarding specified elements of the development before work can proceed.

Planning Approval

Before granting approval, a local authority considers the following potential impacts of a proposed change of use:

• Transport and highway
• Contamination risk
• Flood risk
• Noise

Where the property is a leasehold, ask your solicitor to look for hidden covenants with restrictions that require consents to be obtained from third parties, or covenants affecting the title to the property that restrict its use to commercial only. Also, adjoining premises can sometimes exercise rights over the property. Some types of offices are exempt from Class J status, including premises that have previously been used for other purposes. General Permitted Development also allows a change of use from B1 offices to C3 residential without the need for full planning permission.

Note that Permitted Development rights do not apply to conservation areas, nor to Grade 1 or 2 listed buildings.

Dwellings not situated in a conservation area may extend up to 8m from the rear wall of the original dwelling house for a detached property, and up to 6m for all other properties (e.g. terraced, semi-detached etc.), provided that the extension is no more than 4m in height.

All other existing Permitted Development limits still apply. For example, you still may not cover more than 50% of the garden.

So assuming the property is not in an Article 4 Directions area, you can:

• Add a rear extension or a front porch measuring no more than 3m.

• Install new doors and windows for the porch and carry out internal alterations.

• Convert and occupy the loft space and install roof lights.

• Install power-generating solar panels, excluding wind turbines.

• Extend a detached dwelling by 8m to the rear if a single-storey or 3m if a double.

• Extend a semi-detached or terraced dwelling by up to 6m to the rear, if single storey.

• Extend the height of a single-storey dwelling by up to 4m and no higher than the existing property.

• Two-storey extensions must not be closer than 7m to the rear boundary.

• Extensions must not go forward of the building line of the original dwelling.

• Side extensions must be single-storey with a maximum height of 4m.

• In some areas, side extensions require planning permission and all rear extensions must be single-storey.

• Extensions and outbuildings must not cover more than 50% of the garden space.

• Outbuildings must be single-storey, with a maximum ridge height of 4m for a pitched roof or 3m for any other kind of roof.

• The eaves height of an outbuilding must be no more than 2.5m.

• If the outbuilding is within 2m of the boundary, it must be no higher than 2.5m.

• No outbuilding can be forward of the original dwelling.

All of the above is entirely subject to normal planning design constraints.


Although Permitted Development gives you guaranteed rights in terms of planning, it still leaves some legal ambiguity in terms of lending and selling. Many investors develop HMOs under Permitted Development, unaware that you still need to apply for a Lawful Development Certificate (LDC) after works have been completed to future-proof your investment.

A Lawful Development Certificate can provide assurance to buyers when you come to sell your home, and to lenders when you need to raise finance. However, I secured lending on a HMO without this at the end of 2018. If you require official confirmation of legal compliance under Permitted Development, and official confirmation that your work does not require planning permission, you can apply to your local council for an LDC.


Permitted Development rights can be removed if a Local Planning Authority attaches a condition stating that a dwelling is exempt. Article 4 Directions also remove the right to carry out certain types of ‘permitted development’. If you want to do work that is covered by an Article 4 Direction, you will first need to apply for planning permission. Types of Article 4 Direction vary from council to council and lenders will often be reluctant to lend to HMOs in an Article 4 Direction area.


The following projects never fall within Permitted Development rights:

• Balconies, verandas and raised platforms.

• Two-storey side extensions within 7m of a rear boundary.

• Extensions with eaves higher than 3m (within 2m of a boundary).

• Extensions which exceed 50% of the original curtilage.

• Extensions higher than the height of the original house.

• Extensions over 4m tall or exceeding 50% of the width of the original house.

• Extensions at the front of the house, except a porch less than 3m.

• Unobscured side windows above the ground floor.

• Loft windows that can open when positioned less than 1.7m from the floor.


Regardless of PD rights, you will still need to comply with all applicable building control regulations when carrying out major structural works. Adding steel reinforcement beams or removing a chimney breast, for example, would require building control approval. This can be done by employing a private building control officer or an official council-employed officer; the costs and outcomes are much the same in my experience.