Permitted Development Guidelines for Loft Conversions

You are here:
Home Page > Planning Permission > Permitted Development

Up to 80,000 more householders will be removed from the planning process each year following changes to the planning laws that first came in to force way back in 2008.

The number of families wishing to add space to their home has grown year on year since the last property boom took off in the mid 1990s.

As a result Local authorities have been struggling to deal with the volume of planning applications within the allotted 8-week period.

The Government’s answer has been to change the rules so that the majority of domestic extensions will not now require an application for planning permission.

The most significant change is the removal of any tie-n between the volume of the original house and the permitted volume of the proposed extension.

The criteria will now be a set of guidelines governing the dimensions of the extension. The main guidelines are set out below:

Loft Conversions

* In order to prevent the addition of over-bearing dormers volume caps will remain in place for loft conversions. Up to 50 cubic metres can be added to the roof space of a detached or semi-detached house falling to 40 cubic metres on terraced properties.

The changes mean that most loft conversions involving the construction of a new gable ends will now be permitted.

* Dormers will not be permitted to the elevation of any roof that fronts on to a highway.

* Any extension should be no higher than the ridge line of the existing property

* Dormers should be set back from the eaves by a minimum of 20 cm.

* Verandas, balconies or raised platforms will not be permitted.

If a proposed conversion falls outside of these guidelines it will not necessarily be refused permission but a full planning application will be required.

New rules governing which extensions will be seen as permitted developments have also come in to force:


* Single storey rear extensions to detached properties can be up to four metres deep and four metres high.

* For attached properties, and all extensions with two or more storeys, the maximum depth is reduced to three metres.

* Multi storey extensions should be no higher that the roofline of the existing property.

* Side extensions to be single storey only, no more than four metres high and no wider than half the width of the original property

Volume caps on rear and side extensions have been removed.

All of the measurements should be taken from the ‘Original Property’ which for the purposes of planning matters is taken to mean the property when it was first built or on 1st July 1948 if it was built prior to that date.

If a property is listed or is located within a designated Conservation Area further restrictions will apply. In addition, Local Authorities can change the rules at a local level using either Development Orders of Article 4 Directions

Regardless of whether an application for planning permission is required all domestic extensions require building regulations approval and if the work will affect a wall that is shared with a neighbour it will fall within the scope of the Party Wall Act 1996. The Act requires householders planning to carry out alterations to notify any affected neighbours.

Full details of the new regulations for permitted developments are on the Government Planning Portal -

For more info see the related pages below

Getting Your Final Completion Certificate

Permitted Development Is Great But Don't Forget The Building Regulations

Loft Conversion Information For UK Homeowners

Be Prepared!

Latest Headlines

Visit Our Blog

Search This Site

Take Me Home!

Latest Articles

  1. What Is Vermiculite Loft Insulation?

    Vermiculite Loft Insulation is an echo-friendly alternative to traditional insulation materials

    Read More

  2. The Loft Water Tank Moving And Repositioning

    The old loft water tank will need to be moved if the roof space is being converted into a habitable room

    Read More

  3. Structural Calculations For Loft Conversions

    Structural calculations for loft conversions are of course hugely important to ensure safety and that the proposed plans meet building regulations

    Read More