Do you need a permit in Alphen aan den Rijn? Extensions, dormers and renovations

First: technical and planning rules

Under the Environment and Planning Act (Omgevingswet) every building plan has a technical part, checked against the Buildings Decree (Besluit bouwwerken leefomgeving, or Bbl), and a planning part, checked against the municipality's environment plan (omgevingsplan). Permit free does not mean rule free: the Bbl and the neighbour rules in the Civil Code always apply. This page explains how it works in Alphen aan den Rijn. It is not permit advice: only the online permit check or the municipality (gemeente) can confirm what applies to your address.

Extensions: the national rules

On the technical side, a side or rear extension is permit free if it stands on the ground, is no higher than 5 metres, has no habitable room on the second storey and no roof terrace or balcony (Bbl article 2.25).

On the planning side the dowry rules (bruidsschat) apply: national rules copied into every environment plan in 2024. The extension must be in the rear yard area, starting 1 metre behind the front facade, and more than 1 metre from public space (article 22.27). Within the article 22.36 limits below it can ignore the old zoning plan. Municipalities may change these rules.

Dormers and roof windows

A dormer (dakkapel) is always permit free technically (Bbl article 2.27(2)(a)); a full roof extension is not. On the planning side, a dormer on the rear slope, or a side slope not facing public space, is free under Bbl article 2.29(b), which overrides the environment plan. The conditions are listed below.

At the front, a dormer is only free where no design requirements (welstand) apply (dowry article 22.27(c)). A roof window is free on the rear slope or a flat roof if it sticks out no more than 0.6 metres and stays 0.5 metres from the edges (Bbl article 2.29(c)). On a listed building, and in a state protected area on a slope facing public space, you need a permit (Bbl article 2.30).

• Flat roof.
• No higher than 1.75 m.
• Bottom more than 0.5 m and less than 1 m above the eaves.
• Top more than 0.5 m below the ridge.
• Sides more than 0.5 m from the edge of the roof slope.

Renovating inside the house

Internal work is permit free as long as the load bearing structure and fire compartments stay the same (Bbl article 2.27) and the building volume does not grow (dowry article 22.27(i)). A new bathroom or kitchen usually falls under this. If you remove a load bearing wall, IPLO, the government's information point for the Act, says you need a permit for the technical building activity. In a national monument (rijksmonument) even internal work often needs a monument permit. Normal maintenance stays free.

What the Alphen aan den Rijn environment plan adds

On its Dutch page Dakkapel plaatsen the municipality says a dormer never needs a technical permit. At the rear no planning permit is needed either, if the dormer meets the national conditions. On a side or front slope a design requirement (welstand: whether a building looks right in its setting) can apply. Then a planning permit is needed. You can look up whether that applies to your home in the design rules.

For an annex, such as an extension, conservatory, shed or garage, the municipality repeats the national rules of Bbl article 2.25 and the dowry rules. The key line it adds: if the structure meets the conditions, it is permit free on the planning side and does not have to meet the environment plan rules either. If it does not, the municipality looks at the environment plan for your plot.

If you want to know in advance whether a plan can work, Alphen offers a preliminary request or a planning consultation. Where needed, the municipality asks its environmental quality committee (commissie Omgevingskwaliteit) for advice. Most applications have a decision period of 8 weeks, which can be extended once by 6 weeks. Useful for an extension: the municipality lets you view the building drawings and file of your house, which show how the structure is put together.

Design review, protected areas and listed buildings in Alphen aan den Rijn

Alphen aan den Rijn's design rules (Dutch) are published on the national site for local regulations. Where needed, the municipality asks its environmental quality committee for advice on an application. For small plans at the rear of an ordinary house, design review rarely matters, because the national exemptions take priority there.

According to the municipality, a dormer on a listed building always needs a planning permit, whatever the type of listing. Municipal monuments are in the municipal heritage register, national monuments in the national monuments register. For questions about a protected monument or a building of historic value, the municipality has a heritage desk (Erfgoedloket).

If your house is in a state protected townscape or village area, Bbl article 2.30 and dowry article 22.28 apply. You can check this on the RCE map of protected areas and in Rules on the map.

Owners' associations and renting

A permit only means the government agrees. In a flat, the facade, roof and usually the load bearing walls belong to the owners' association (Vereniging van Eigenaren, or VvE). A dormer, extension or new opening then needs a VvE decision under the deed of division (splitsingsakte). The municipality does not check this.

If you rent, you need the landlord's consent for an extension, dormer, kitchen or bathroom. The landlord must reply within 8 weeks and may only refuse if the home becomes harder to let or loses value (Civil Code article 7:215).

How to check it yourself

Work through these steps in order for your own address. The national portal is in Dutch and you need DigiD to apply. The municipality has no English building pages; the national government explains the system in English on Government.nl.

Questions can go to the municipality on 14 0172. If you want to know what is possible structurally, contact us for a visit by Stas. For a full renovation we include the permit question in the planning.

• Run the permit check on the Omgevingsloket.
• Look up the rules for your plot in Rules on the map.
• Read the municipal pages on the dormer and the annex (Dutch).
• For a side or front dormer, check the design rules.
• Check Erfgoed en monumenten and the national monuments register to see whether your building is protected.

Frequently asked questions