Extension or addition: what is the difference?

Would you like more space in your home? You will often hear the Dutch terms aanbouw and uitbouw. They are sometimes used interchangeably. For your project, the key question is which space you want to add or enlarge and how it will connect to your existing home.

What do we usually mean by an addition?

People often use aanbouw for a new space beside or behind the home with its own purpose, such as a utility room, workspace or extra bedroom. It connects to the house but does not have to directly enlarge an existing living room or kitchen.

And what is an extension?

An uitbouw usually enlarges an existing room. Moving the rear wall, for example, can create more space for an open-plan kitchen or a larger living room. The new and existing areas then form one space. The term alone does not determine the technical approach or whether a permit is required.

What questions help you choose?

• Purpose: Do you want to enlarge an existing room or add a separate space?
• Layout and daylight: How will the old and new parts connect, and how will the change affect daylight in your home?
• Structure and services: What changes are needed to the façade, heating, electrical work or plumbing?
• Budget and schedule: What finishes do you want, and when does the space need to be ready?

Do you need a permit?

That depends on the specific project and its location. Use the permit check in the Omgevingsloket to see whether your project requires a permit or notification. Also read how to check permit requirements for a renovation. Discuss early which building drawings and calculations your project requires. Ponto Services can help you plan the preparation and construction work.

See how we manage an addition or extension and explore our complete renovation with an extension in Amsterdam Zuid.

Discuss your extension plans

You do not need to know the exact term for your plans yet. Tell us what you want to change, where the property is located, your approximate budget and when you would like to start. We can then discuss which type of extension suits your home and your needs.

Updated: 16 October 2026. General information; check the rules for your address through the Omgevingsloket.