What needs listed building consent?

Any work that affects the character of a listed building as a building of special architectural or historic interest — inside or out, including fixtures and curtilage structures. In Wales, Cadw sets the national framework and your local planning authority decides consents; in England, it is your local planning authority with Historic England advising. If in doubt, ask before you touch anything — unauthorised works are a criminal offence.

Can I extend a listed building?

Often, yes — if the extension is well designed, subservient to the original and doesn’t harm its significance. A clear understanding of what makes the building special is the starting point for any successful application.

Can I put in double glazing, insulation or a heat pump?

Sometimes. Each needs consent and careful design. Secondary glazing, breathable insulation in the right places and well-sited heat pumps are often achievable. The key is improving performance without trapping moisture or harming historic fabric.

Renovating a listed building

A practical guide to renovating, extending or repairing a listed home in Wales or England — listed building consent, what you can change, and how to work with the fabric.

Owning a listed home is a privilege and a responsibility. The building has outlived everyone who built it, and the job now is to make it work for the next hundred years without losing what makes it special.

Listing covers the whole building

Listing applies to the entire building — inside and out — plus fixtures and, often, structures within its curtilage. Grade doesn’t change that: a Grade II house is protected just as fully as a Grade I one. What varies is how significant each part is, and that is what decides what you can change.

Understand significance first

Before designing anything, understand the building: when each part was built, what’s original, what’s been altered, what matters most. A clear statement of significance is what good applications are built on — and it often shows that later, less important parts give you more freedom than you thought.

Repair, don’t replace

The default with historic fabric is repair. That means:

Lime, not cement. Old walls need to breathe. Cement mortars and renders trap moisture and cause decay.
Matching materials. Like-for-like timber, stone, slate and brick.
Minimal intervention. Do what’s needed, and make it reversible where possible.

Structural problems

Many listed homes have structural issues: bulging walls, decayed timbers, failed lintels, movement from shallow foundations. These can almost always be solved — but they need an engineer who understands historic construction, so that the fix respects the building rather than replacing it.

The best structural repair in an old building is the one you can’t see.

Modern living, sensitively

Kitchens, bathrooms, heating and insulation can all be brought up to date. The trick is to put new services where they do least harm, improve thermal performance with breathable materials, and design any extension as a confident, clearly modern addition rather than a pastiche.

Where to start

A Feasibility Study for listed and heritage buildings includes a deeper constraint review: what the listing protects, where the structural issues are, two or three options in 3D, the risks and a cost range — and the surveys you’ll need before detailed design.