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 deeds.

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.