Rear extensions are the most common project we're asked about in Worthing, and the honest answer is "often, but not always". Whether the Party Wall etc. Act 1996 applies comes down to how close your foundations are to next door, and whether you're touching the shared wall.
The 3-metre rule is usually the trigger
Most single-storey rear extensions don't touch the party wall itself, so people assume the Act doesn't apply. But there's a second trigger that catches a lot of Worthing's terraced and semi-detached homes: Section 6, the 3-metre rule. If you're excavating foundations within 3 metres of a neighbour's building and to a depth lower than their existing foundations, you must serve notice, even if you never touch their wall.
Given how close together many Worthing properties sit, standard extension foundations frequently fall inside that 3-metre zone. There's also a 6-metre rule for deeper excavations under a 45-degree line from the neighbour's foundations, which catches basements and some larger builds.
When you probably don't need to
If your extension's foundations are more than 3 metres from any neighbouring structure, don't touch or tie into the party wall, and don't come within the 6-metre deep-excavation line, the Act may not apply at all. A quick check of your plans usually settles it.
Why it's worth getting right
Even where notice is required, the process is routine for a straightforward extension, often a single notice and a simple award with a schedule of condition. Getting it done early means it never delays your build, and the schedule of condition protects you if your neighbour later claims your work cracked their wall. Skipping it when it was required is the expensive mistake.
Planning a rear extension in Worthing? Send us your plans or call 01903 372418 and we'll tell you in minutes whether the Act applies.
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