Granny Annexe Planning Permission in Mountain Ash

Mountain Ash Annexes: Caravan Act, Permitted Development, Or Full Application

Mountain Ash families often assume a granny annexe is either always simple or always complicated, the reality depends entirely on how it’s built and used. The Caravan Sites Act 1968 defines a caravan as a structure capable of being moved by road, within strict size limits, and a genuinely mobile annexe meeting that definition can sometimes avoid planning permission altogether.

Permitted development under Class E covers incidental outbuildings in Mountain Ash, subject to height and coverage limits, but not genuine self-contained living accommodation with its own bedroom, bathroom, and kitchen used independently.

We assess your specific Mountain Ash property and plans against all three routes honestly, rather than assuming the most complex one applies by default. A Mountain Ash annexe needing full planning permission usually needs both, our Building Regulations drawings in Mountain Ash service covers the technical compliance side, and our structural calculations in Mountain Ash service covers the engineering detail.

Right Route Confirmed

Caravan Act, permitted development, or full planning

Caravan Act Route

Movable structures that may need no permission at all

PD Size & Siting

Permitted development limits checked properly

Council-Ready

Applications built to be approved

How We Help in Mountain Ash

We begin every Mountain Ash annexe project with an honest assessment of the actual plans, size, mobility, and intended use, before any design work begins.

Where the Caravan Act or permitted development genuinely applies to your Mountain Ash project, we confirm that properly, usually via a Lawful Development Certificate, rather than defaulting to a full application that isn’t needed.

Where genuine self-containment means a full application is required, we build that around what Mountain Ash’s council specifically expects to see.

What Mountain Ash Annexe Clients Actually Get

Every Mountain Ash annexe assessment starts with an honest read on which of the three routes genuinely applies, not an assumption that defaults to the more complex, more expensive option.

We check the real mobility and size of a proposed Mountain Ash structure against the Caravan Act’s actual legal definition, rather than assuming it qualifies.

Where a Mountain Ash annexe genuinely needs a full application, we say so directly and build it around what the council expects to see. If you need help with a granny annexe, give us a call on 0330 133 5316 or fill in the form below.

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Mountain Ash Annexe Planning Questions Answered

What determines if my Mountain Ash annexe needs planning permission?

This genuinely depends on your specific plans for Mountain Ash, we check whether the structure is mobile, incidental, or self-contained before advising either way.

What size limits apply to a caravan-style annexe in Mountain Ash?

The Caravan Sites Act 1968 sets the limits, 20 metres long, 6.8 metres wide, 3.05 metres internal height, and the structure must be moveable by road in one or two sections, we check whether your Mountain Ash plans genuinely meet this.

What outbuilding rules apply to a Mountain Ash annexe?

It depends on genuine use, an incidental Mountain Ash outbuilding can qualify under Class E, but introducing real sleeping accommodation used independently takes it outside permitted development regardless of size.

What makes an annexe a separate dwelling in Mountain Ash?

Genuine independence is the test in Mountain Ash, if the annexe could function as a separate home on its own, full planning permission is almost always the realistic route.

Is a Lawful Development Certificate worth it in Mountain Ash?

Strongly recommended for Mountain Ash annexes, an assumption that a structure qualifies isn’t the same as formal confirmation, and a Lawful Development Certificate closes that gap.

Can you manage everything for my Mountain Ash annexe project?

Yes, we coordinate every part of a Mountain Ash annexe project, from establishing the correct route through to building regulations sign-off, so nothing falls through the gap.