• ACG Builders

Thinking of extending your home?

Welcome to ACG Builders first news post... we're going to be looking at some of the items you should consider when looking at extending your home.

If you need any further advice, or assistance in your home extension project please don't hesitate to contact us on 01903 716 895! We have a vast portfolio of home extension projects throughout West Sussex and it's surrounding areas and can offer high quality, competitively priced home extensions for all sizes of project.


In the UK you have two potential routes to gain "permission" to undertake your home extension.

The first of which is traditional Planning Permission, where you will put together an application to your LPA (Local Planning Authority) and they will consider your proposals, potentially request changes/amendments and then come back to you with a final outcome, there is obviously much more to this process including plans, searches, aesthetics, traffic, infrastructure and many other considerations but as the majority of new home extensions are done under Permitted Development, we will not delve too deep into the Planning Permission option as we could be writing for days!

The second of which is Permitted Development, where you have automatic rights to carry out construction to your house, however there are still some stringent requirements that must be met. This normally consists of the following: -

The normal restrictions are extensions on semi-detached property would be no further than 6M out from the rear boundary, on the condition this covers no more than 50% of the existing garden and assuming the property has not been extended before.

On a detached property, the same restrictions apply but instead you are allowed to go no further than 8M out from the rear boundary.

The other considerations are that it should be in keeping with the existing property's aesthetics, should be no taller than 4M, or 3M if within 2M of a boundary.

When constructing large extensions, you will also need to service notice under the neighborhood consultation scheme - this is a simple task and is essentially notifying your neighbors to your plans to extend your home. They can potentially object or query, but there is a process to resolve any disputes.

Please note: this list is not exhaustive, and not legal advice - just a basic overview of what is required - the process is more indepth than outlined, but this is merely to give you some starting points to assist your plans. If you require assistance throughout please contact us to quote for your project on 01903 716 895 or


If you are planning to build over an existing drain, you will need to contact your local water authority to gain a "build over agreeement" this process can often take up to 12 weeks, so it's best to get this underway as early as possible.

The water authority will need to see plans of the existing drainage (often available for purchase from their website) and you will need to mark up the proposed drainage amendments. If you need assistance in designing, amending or installing new drainage our Groundworks team can assist you!


Another factor to bear in mind when building within three metres (or in some cases, six metres) of neighbouring buildings is the Party Wall etc Act, which requires you to formally notify the adjoining owners two months in advance of the proposed project.


Is there suitable access to get the required plant equipment and materials to the extension area? If not, this may have to come through the house which may cause incredible disruption, be craned over, or done by manual labour - all of these can cause significant complications and cost increases for your chosen contractor.


All home extensions will need to comply with building regulations which covers everything from structural adjustments, foundations, lintels etc to even the amount of insulation used in the roof and floor structures.

The building inspector will also need to attend the site during different construction phases to check and sign off the work carried out. Assuming this is all done correctly, you should be issued a certificate of compliance afterwards - ensure this is not forgotten as it will be a key requirement if you choose to sell the property on at a later date.

You may also need to check if your contractor has allowed for the building inspectors fees within their quotation - you can either appoint your local councils inspector, or you can appoint alternative approved 3rd party inspectors.


Whilst this list is not exhaustive, hopefully it will help you start your home extension planning. If you need assistance with any of the items listed herein, do not hesitate to get in touch on 01903 716 895.