A Simple Guide for Core Cabins

We get it — nobody wants to fall foul of planning laws, and the whole process can feel daunting if you haven’t dealt with it before. The good news is that many Core cabins fall under Permitted Development (PD), meaning you may not need full planning permission at all. It mainly depends on your property, where the cabin will sit, and how you plan to use it.

To make things easier, here’s a clear, no-jargon guide to help you understand what applies.

Permitted Development Checklist (Must Be Met)

1. Location on Your Property

✔ The cabin must sit within the curtilage of your main home
(curtilage = the garden or land directly linked to your house)
✔ It must not be placed in front of the principal elevation
(principal elevation = the front of your house)

2. Height Limits

✔ Max 2.5m high if the cabin is within 2m of any boundary
✔ Up to 3m for a dual-pitch roof or 2.5m for single-pitch if more than 2m from the boundary
✔ Total height must not exceed 4m

3. Size Limits

✔ Outbuildings must not cover more than 50 percent of your overall garden
✔ Tighter rules apply to designated areas:

• AONB – Area of Outstanding Natural Beauty

• NP – National Park

• CA – Conservation Area

• WHS – World Heritage Site

4. Use of the Cabin

✔ Must be incidental to the main house
(office, studio, gym, hobby space, occasional overflow)
✘ Not allowed as a self-contained dwelling
✘ Not suitable as primary sleeping accommodation under PD
✘ Holiday lets almost always require planning permission

5. Services & Building Regulations

✔ Electrics must comply with Part P of Building Regulations
✔ Outbuildings are often exempt from full Building Regs if:

• Under 30m², and

• Not used for sleeping

Must-Haves to Stay Within PD Rules

To keep your cabin safely within Permitted Development:

• Keep height at 2.5m if it’s near a boundary

• Place it behind the front wall of the house

• Use it as an ancillary space, not a separate home

• Avoid foundations that imply permanent residential use

• Ensure no primary sleeping function

• Keep outbuildings under 50% of your garden area

• Use certified trades for electrics

Who to Speak to if You’re Unsure

If you’re not certain whether your cabin fits PD rules, your local authority can help. The best people to contact are:

1. Planning Duty Officer

A free, informal service in most councils. They can quickly tell you whether your project sounds like PD.

2. Planning Validation Team

They check if your documents and site plan meet the requirements for a formal application.

3. Pre-Application Advice Service

Usually a small fee. You’ll receive written advice on whether planning is required and how likely approval is.

4. Your Council’s Online Planning Portal

You can:

• Check whether you live in an AONB, Conservation Area or similar

• View past applications

• Read local guidelines

A quick call to the Planning Duty Officer is often the fastest way to get clarity.

When Planning Permission Is Needed

You’ll likely need planning permission if you intend to:

• Use the cabin as a holiday let or rental

• Create self-contained living accommodation

• Place the cabin in a Conservation Area where it’s visible from the road

• Build next to a Listed Building

• Exceed height or footprint limits

How We Support You

We walk you through what applies to your property in plain English. We’ll explain whether your cabin is likely to fall under PD and, if not, what the planning route looks like. If you do need approval, we can advise on the steps involved and what your local authority typically expects — so you can move forward with confidence, not confusion.