• Essential Guide: key procedures in extending your property

    Feb 18th, 2017

    The following guide provides a brief overview of key procedures that apply to extending your home.  Each of the four elements scratch the surface and by no means provides a full and comprehensive guide.  If you are considering extending your home professional advice should be sought from the outset.

    Full Planning Permission or Permitted Development?

    Loft conversions, single and two storey extensions can all fall under Permitted Development (PD) however there are strict rules which must be observed.  As an example, a semi-detached house can be extended with a single storey rear extension to a depth of 3m or a detached house by 4m, these limits have been temporarily increased to 6m and 8m until 30th May 2019 however if an extension is within 2m of a boundary the eaves height cannot be greater than 3m.

    PD rights can be withdrawn if your Council has made an Article 4 Direction, the property is Listed or your property is on Designated Land e.g. a Conservation area, Area of Outstanding Natural Beauty etc. so beware!

    If your extension fails to meet PD then you could apply for Full Planning Permission and so all may not be lost.

    Further detailed information can be found on the following link:


    If your property is Listed or in a Conservation area, a Listed Building Application and/ or Conservation area consent will likely be needed.


    Building Regulations

    Once Planning Permission has been secured or PD established an application demonstrating how the proposed extension will meet the current Building Regulations would be required.

    This can ordinarily be by a Full Plans Application or under a Building Notice.  The submission of a Building Notice allows construction works to commence within 48 hours however works undertaken are at risk if that work is non-compliant.

    Alternatively detailed drawings can be produced and submitted under the full plans route which are reviewed by the Building Control Authority.  Once approved, works can progress free from the risk that the build is non-compliant.

    The Building Regulation application can be made to either the Local Authority or an Approved Inspector.

    The Building Regulations may also apply to certain changes of use.  For example a lettable cottage that will be turned into a holiday let will no longer comply with the requirements associated with a holiday let resulting in up-grading to meet additional requirements specified in the regulations for which additional building work may also be required.


    The Construction (Design and Management) Regulations 2015 (CDM)

    The CDM Regulations (Health and Safety matters) applies to all building and construction works in the UK and includes new build, demolition, refurbishment, extensions, conversions, repair and maintenance.

    The regulations now apply to both domestic and non-domestic clients which is a fundamental change from the CDM Regulations 2007.

    As a domestic owner commissioning construction works you would therefore have legal responsibilities under these Regulations which cannot be ignored.  It is essential that whoever you appoint either as a consultant or contractor that they can demonstrate adequate competence, other duties include:

    • Make suitable arrangements for managing a project in relation to Health and Safety including allocation of sufficient time and resources.
    • Provide Pre-Construction information to designers and contractors (relevant information),
    • If there is more than one Contractor on site, at any one time, appoint as soon as practicable a Principal Designer and Principal Contractor.
    • Ensure that before works start that a suitable Construction Phase Health and Safety Plan is implemented.

    For further information: https://www.citb.co.uk/documents/cdm%20regs/2015/cdm-2015-clients-interactive.pdf

    Be aware that if your project is for a property to let out or forms some type of business you cease to be a domestic client under these Regulations which mean your responsibilities become much more onerous.

    The Party Wall etc. Act 1996

    If you’re extending your home there is every possibility that the Party Wall etc. act 1996 will be invoked even where you own a detached property.  The Act applies generally in the following circumstances:

    Section 1: Line of Junction notice – Notice is required for constructing an extension up to the boundary (the line of junction) or across the boundary as a new Party Wall.

    Section 3: Party Structure notice – Undertaking any work to a Party Wall, being a wall that separates two or more properties will require notice under section 3.  Undertaking any works to a Party Fence Wall, typically being a garden wall separating land will also require notice under section 3 or a Party Structure, the floor separating flats.

    Section 6: three metre or six metre notice – Adjacent excavation within 3m of and to a lower depth than your neighbours’ foundation will require notice under section 6.  Some excavations within 6m of your neighbours’ foundations also require notice depending on the depth of the excavation.

    In general, if you are flanked by property you will likely need to serve Party Wall notices if you are constructing a basement, an extension, a loft conversion, removing chimney breasts or inserting a beam into the Party Wall.

    Failure to serve Notice(s) is a statutory offence and could result in an injunction.

    For further information: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/523010/Party_Wall_etc__Act_1996_-_Explanatory_Booklet.pdf

    Robert C G Turner Ba(Hons), BSc (Hons), AaPS, MFPWS, MRICS

    Chartered Building Surveyor / Director