House extension requirements - What you need to achieve
Before you can start a house extension on site you will have needed to have obtained certain approvals,
plans and documents, etc. and researched other affecting issues that could prevent you from building your house
extension dreams. Failure to recognise and investigate these other but less obvious issues of a house
extension requirements could land you into a lot of trouble, delays and further expense.
Most homeowners realise the obvious house extension requirements in having to obtain
plans and specifications for the planning permission and building regulations approvals.
However, many homeowners forget to investigate things like restrictive convents that may be on the house
Many homes will almost certainly have some form of restrictive covenant on them that prevents or tries to
control what else you can install on the site or to the existing property.
These are usually installed by the original developer or land owner preventing a new homeowner from installing
unpleasant items that could put off other purchasers of neighbouring properties also up for sale.
Fortunately many of these restrictive covenants relating to house extension requirements are non-enforcable due
to deaths and long time periods involved. Others can have a real sting in the tale so always check first.
Some of the restrictions on covenants relate to protecting the distinctive character so limiting
alterations to the property could have been important for the original land owner.
Discharging or complying with the terms of the covenant and obtaining written permission is often more difficult
with older properties. This is because the original land owner or their estate or company is no longer in
existence so impossible to trace and therefore comply. If the home owner carries on with the home
extension than this can cause problems for future homeowners or their financing arrangements. This can often
be overcome with the payment of a one off indemnity insurance fee to protect future owners from aggrieved
beneficiaries of the covenants requiring retrospective consent.
Many home extensions now build close to a neighbours wall including party walls. For many years London has
benefited from a party wall act which seeks to reduce the potential for damage claims from neighbours.
In 1996, the government introduced new party wall legislation for the entire country. Therefore, if you are
excavating within 3M of a neighbours walls or within 6M of a party wall then you will probably need to
engage the services of a party wall surveyor to discharge you duties. There are added criteria details to
these distances such as excavating lower than the invert of the neighbouring wall and if the bulb of pressure
from your foundations travel through the party wall itself. Home extension designers or architects can
offer this service as well but most pass it over an experienced chartered party wall surveyor if
compliance is required.
Not only excavations within the minimum distances stated above require compliance
with the party wall act, but any works to a party wall (that may be affected) require notices to be served under
the party wall act. Works such as installing a new beam end onto a party wall will require compliance.
Your house extension scheme may be very large and the time spent on site by your builder may require
compliance under the Construction Design and Management (CDM) regulations being health and safety.
Failure to comply and engage the right people can result in prosecution.
The CDM 2007 Regulations apply to most common building, civil engineering and engineering construction work. You
must notify HSE of the site if the construction work is expected to either:
- last longer than 30 days; or
- involve more than 500 person days of construction work;
HSE should be notified in writing before construction work starts; you can use form F10. Your notification
should be sent to the HSE office nearest to the proposed site.
Are you building near or over a main sewer? - failure to obtain the correct permissions will again result in
delays and possible prosecution. Another important aspect of house extension requirements.
Not all public sewers are located within the main road well away from the new home
extension. Many properties have shared drainage at the rear of the property for example and now any
shared drainage system pre 1st October 1937 are deemed to be public sewers requiring a 'build over consent' from
your local water board dealing with drains and sewers if you are building within 3M of these drains.
Regretfully, this aspect of main sewers is often not picked up until the home extension
scheme is submitted for consent through the Building Control Service. If it is 'red flagged' on their systems
they will advise you what to do before they are able to issue your approval.
'Building Over Agreements' usually require a formal submission to the local water board enclosing the plans with
a fee dependant upon the size or classification of drain you are building over or near. Typically this can
range from £300.00 to £800.00
If you have employed an experienced and professional home extension designer or architect then they
would have already advised you of the potential issues during the design build up process as part of their
own duty of care to their clients.