By this stage the survey has been completed, you will have received an estimate for your extension, initial plans and drawings will have been created and you will have signed the contract.

Planning permission is supposed to balance the rights of the owner to use their land as they wish with the rights of the local community to maintain their quality of life. However despite the large numbers of planning applications submitted each year, the process is not at all user friendly and can be very stressful for home owners with no experience of the system.

Marble Construction’s designers and architects have the knowledge and experience to ensure planning permission is granted as quickly as possible and without problems.

If the extension is lucky enough to fall within the following conditions and the area is not subject to article 4 of the town and country planning act 1948 it may be possible not to have to apply for planning permission. This will greatly decrease the time and cost of the project. See conditions listed below:

  • The extension is no more than 70 metres cubed or increases the original house’s size by no more than 15% in semi or fully detached properties
  • The extension is no more than 50 metres cubed or increases the original house’s size by no more than 10% in terrace or end of terrace properties.
  • The new extension roof will not be taller than the existing house.
  • Any part of the extension within 2 metres of a garden boundary must be no taller than 4 metres or 3 metres if a flat roofed structure.
  • No part of the extension will be closer to the public footpath or road than the existing property unless the extension is over 20 metres away.
  • All additions to the original house must be no more than half the size of the original garden space.

Notes: The definition of original house is the property’s size as of the 1st of July 1948, these conditions are irrelevant in a listed building and volumes are calculated from the exterior of the space not the interior.







Listed Buildings and conservation areas

If the property is a listed building it will be tougher to get planning permission. However, any work done on listed buildings is tax deductible with materials and labor not being subject to V.A.T.

To gain planning permission on such properties it may be necessary to make the design more in keeping with the property or local area. This can be achieved by using reclaimed bricks in a similar style to the house, using Velux conservation windows and using natural slate roofing. All of which will increase the aesthetic appeal of the property, but also the cost.

Tips and tricks to gain or avoid needing planning permission

  • If your extension is detached from your property by more than 5 metres it doesn’t count as an extension and will not require planning permission.
  • Basements, cellars or extensions built lower than pre-existing ground level do not require planning permission. However the practicality is often quite low.
  • reduce the probability of overlooking neighbors by avoiding balconies, roof gardens and windows in side walls.
  • avoid using too much garden space (over 50%) in built up areas as this is called over-development.
  • Model your extension in a similar fashion to an existing extension on a house in the same area.
  • Be careful not to obstruct light from entering neighbor’s windows, this is defended by the “right to light”
  • make sure there is ample parking for the occupants of the house.
  • woo the council with landscaping and planting in the designs.
  • Make the extension in-keeping with the style of the existing house and area
  • Side extensions should be set back from the front of the property to avoid old and new bricks and joints clashing.
  • Make sure the extension does not block the line of sight of drivers.


Even when planning permission is granted it is likely there will be conditions attached, these can include anything from the work being started within three years to an eighteen week delay requiring your garden to be dug up by a team of archaeologists.


The penalties for non compliance or failure to get planning permission are very severe. People in the past have been heavily fined, had their homes demolished and people can theoretically be imprisoned as a last resort.


Building Regulations

This is separate to Planning Permission but just as important. Without a final certificate for all work carried out, it can be hard or impossible to sell the house as many people will believe it is structurally unsound.

Marble Constructions are fully certified and regulated. All our work is to a high standard above what is asked for by the Building Control officers who oversee all building work.

The different sections which a structure must pass to be certified by building regulations are:

A. Structure

B. Fire safety

C. Site preparation and resistance to moisture

D. Toxic substances

E. Resistance to the passage of sound

F. Ventilation and condensation

G. Hygeine

H. Drainage and waste disposal

J. Heat producing appliances and fuel storage systems

K. Stairs, ramps and guards

L. Conservation of fuel and power

M. Access and facilities for the disabled

N. Glazing (materials and safety)

P. Electrical Safety

The construction site is inspected by the building inspector at certain stages as well as random spot checks.


Stages for inspection:

  • Start
  • Excavation
  • Construction of foundations
  • Damp proofing
  • Over site concrete
  • start of drainage changes
  • End of drainage construction and testing
  • Job completion

Note: It is a criminal offence to impede or obstruct Building Control Officers or to deny them entry to the construction site during reasonable hours.



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