Building a conservatory
A conservatory or garden room is one of the most atmospheric ways to extend your living space: lots of glass, lots of light and a direct connection to the garden. In many cases at the rear of your home you can build a conservatory permit-free, but whether that applies depends on the dimensions, your plot and the type of house. On this page you can read when you need a permit, what the difference is between a conservatory and a canopy or veranda, which building requirements apply and what a conservatory drawing at Tekenpunt costs.
A conservatory or garden room is permit-free if it sits entirely within the rear plot area, stays within the maximum built surface of the Building Works Decree (Bbl) and is no higher than 5 metres. A permit is always required on a corner plot, at the front facade or for a listed building. The Bbl insulation requirements apply even without a permit, as a conservatory is thermally part of the home. A construction drawing from Tekenpunt starts at €595; the permit application costs €500.
What exactly is a conservatory or garden room?
The terms conservatory and garden room are used interchangeably, but in practice refer to the same thing: an extension to the home with a facade cladding that consists largely of glass. Unlike a canopy or veranda, a conservatory is an enclosed space that forms a thermal part of the home. Doors, windows and the roof are closed, so the space can be heated and used all year round.
A conservatory also distinguishes itself from an ordinary extension by its glass percentage. In a standard brick extension, masonry facades dominate; in a conservatory, the facade consists predominantly of glass, aluminium or steel profiles with glazing. This has consequences for the structure (lighter load-bearing structure, but also more wind load), the insulation requirements and sometimes the aesthetic review.
A canopy or veranda is different: it has a roof but no closed side walls. Outside air can circulate freely through the space. That may sound like a minor detail but it has major consequences for the permit rules and the structural requirements. A canopy falls under a different category in the Buildings in the Living Environment Decree (Bbl) than a closed conservatory. This page is about the closed conservatory or garden room that forms part of the home.
When is a conservatory permit-free?
Under the Environment Act (in force since 1 January 2024), the permit-free scheme for associated structures is laid down in the Buildings in the Living Environment Decree (Bbl). The old terms Wabo and Environmental Law Decree (Bor) have been abolished.
A conservatory falls as a closed extension into the same category as a regular extension or addition: the associated structure. The Bbl criteria for permit-free construction are in outline:
1. Location in the rear garden area The conservatory must lie entirely within the rear garden area. The rear garden area is the part of your plot that starts 1 metre behind the (extended) front facade of the home and does not border publicly accessible land such as a pavement, park or public road. If the conservatory extends even partially outside the rear garden area, a permit is required.
2. Maximum built-up area The Bbl sets limits on the total amount of associated structures you may build in the rear garden area. This limit depends on the size of the so-called building plot and is regulated in steps: on a smaller plot you may build proportionally more, but there is an absolute maximum. Always count existing outbuildings: a shed, storage unit or garage already in the garden eats into your available space.
3. Maximum height An associated structure may be a maximum of 5 metres high. If the conservatory is built directly against the house, additional Bbl rules apply regarding eaves height and roof form. With a pitched roof, take into account the ridge and eaves height; a flat roof generally stays within the limits more easily.
4. Use A conservatory directly adjoining the dwelling may have the same use as the dwelling: living, dining, relaxing. An outbuilding more than 4 metres from the dwelling may only have a subordinate use and may not be fitted out as a bedroom or independent dwelling.
Always run the permit check These Bbl criteria apply to the environment plan activity (the spatial element). But the Environment Act splits construction into two activities: the environment plan activity and the technical construction activity. The technical requirements (structural safety, fire safety, insulation) also apply to permit-free construction. Do the permit check via the Omgevingsloket (omgevingsloket.nl) to be sure whether your plan is permit-free.
When do you need a permit for a conservatory?
There are situations in which a conservatory always requires a permit, even if you are building at the rear:
Corner house If you live on a corner plot, your side garden area borders a public pavement or road. A conservatory on the side of a corner house is therefore never permit-free, even if it is effectively 'behind' the front door. The position relative to publicly accessible land is decisive, not the compass direction.
Front facade or front garden area Every conservatory on the front facade or in the front garden area (the part up to 1 metre behind the front building line) always requires a permit. If you want to extend on the side of the house, check whether that side falls within the rear garden area.
Exceeding the area limits If the intended conservatory exceeds the maximum permitted built-up area in the rear garden area, a permit is required for the excess.
Listed monument or protected town or village scene If you live in or near a national listed monument, municipal listed monument or protected scene, stricter rules apply. For national listed monuments, almost all external building activities require a permit, including a small conservatory that would be permit-free elsewhere.
Additional rules in the environment plan Your municipality can impose stricter rules than the Bbl through the environment plan. Some municipalities further restrict the height, area or appearance of extensions. Permit-free at national level therefore does not mean that the municipality has no further say.
Where an environmental permit is required, Tekenpunt handles the complete application including site plan, floor plans and facade drawings. Tekenpunt gets 90% of applications through aesthetic review in a single round.
Construction requirements: the rules apply even when permit-free
A common misconception is that 'permit-free' also means 'rule-free'. That is not the case. The Bbl sets construction requirements that always apply, even when no permit needs to be applied for. For a conservatory the following points are relevant:
Insulation (thermal envelope) A conservatory that forms a thermal part of the heated home must meet the Bbl insulation requirements for the thermal envelope. This means the glazing must achieve a minimum insulation value (expressed as a U-value) and the connection to the existing facade must be thermally well executed. Cheap single glazing or old double glazing does not meet the standard. For a conservatory with a glass roof, additional requirements apply to the roof surface.
Structural safety However light a conservatory's structure may look, it must withstand wind loads, snow loads and its own weight. With a glass roof, the bearing and connection points are critical. If the conservatory is built against a load-bearing part of the house, such as the rear wall, and a wide opening is created, a steel beam is needed to take over the load-bearing capacity. In that case a structural calculation is legally required, even without a permit.
Watertightness and drainage A poorly draining glazed extension will almost certainly lead to leaks, particularly at the junction of the glazed roof with the existing facade. The detailing at that point is critical and must be properly worked out in the drawings so that the contractor knows what to do.
Fire safety The escape route from the home must not be blocked by the conservatory. Bear this in mind when designing doors and passageways.
Tekenpunt incorporates these requirements as standard in the construction drawings. The drawings are suitable as working drawings for the contractor and as the basis for the structural calculation by the KIWA-certified structural engineer.
The difference between a conservatory, a canopy and a veranda
For the permit rules and the building technical requirements, the exact way the space is constructed matters. Below is a brief overview:
Conservatory or garden room (closed extension) Closed space with glass walls and roof, forming a thermal part of the house. Falls under the Bbl category of associated structure. The same rules as a regular extension, but with specific insulation and glass detail requirements.
Canopy or veranda (open extension) A roof on posts or against the facade, without closed side walls. The space is in open connection with the outside air. Also falls under the Bbl but has different requirements regarding maximum area and use. A canopy counts towards the built-up area of the rear garden area, but no thermal requirements apply because there is no heated envelope.
Glass sliding door without a canopy Sometimes only the rear facade is replaced by a large glass sliding door or folding wall, without a separate roof being added on the outside. In that case you are altering the facade of the existing home but not adding any extra building volume. That falls into a different category.
If you are not sure which category your plan falls into, send your sketch or idea to Tekenpunt. We assess it free of charge and tell you which drawings you need.
The drawing process at Tekenpunt
Tekenpunt is a drawing office, not an architect. You work directly with a draughtsman who specialises in renovations for private individuals. The process for a conservatory or garden room drawing works as follows:
1. Intake and dimensions You share your wishes via the quote form on Tekenpunt.nl. We discuss the desired dimensions, the position of the conservatory and the connection to the existing facade. If you do not have existing floor plans, we discuss how you can best provide the measurements.
2. Draft drawings We produce an initial set of drawings: floor plan existing and new, facade drawings and a cross-section. For a conservatory the cross-section is especially relevant as it shows the connection to the roof and the facade. You will have the opportunity to give feedback.
3. Final drawings After incorporating the feedback we deliver the final construction drawings. These are suitable for permit-free construction, a permit application and the structural engineer.
4. Add-ons If you also need a structural calculation (always advisable for a conservatory with a steel load-bearing structure or when a facade is being opened up), you can add it as an add-on. If you want to see what the end result will look like in advance, the 3D visualisation is a good choice.
Delivery time and experience The standard delivery time is approximately 4 weeks. With rush processing the drawings are delivered within 1 to 2 weeks. Tekenpunt has been operating since 2016 and has completed more than 800 projects , including many conservatories and glazed extensions.
Costs: drawing and add-ons for a conservatory
A construction drawing for a conservatory or garden room starts at Tekenpunt from €595. That price includes the basic plans: site plan, existing and new floor plan, elevation drawings and cross-section. The exact price depends on the scope and complexity of the project and is always fixed in advance in the quote: no surprises afterwards.
In addition, there are add-ons that you can choose to include:
| Add-on | Price |
|---|---|
| Building permit application | €500 |
| Structural calculation (KIWA structural engineer) | €700 |
| 3D visualisation | €400 |
| Express processing (1-2 weeks instead of 4 weeks) | €495 |
When do you need which add-on?
- Building permit: only if your situation is subject to a permit requirement. You'll know for certain after the permit check. Tekenpunt handles the complete application with the municipality.
- Structural calculation: needed if the conservatory is attached to a load-bearing part of the house or if an opening is made in the rear façade for a passage. A KIWA-certified structural engineer calculates the required dimensions of the supporting structure.
- 3D visualisation: useful if you want to see what the conservatory will look like before sitting down with the contractor, or if you want to show the plan to a partner or neighbour.
- Express: choose this if you need to submit a quote to a contractor quickly or have a deadline for a permit application.
Via the quote form on Tekenpunt.nl you receive a tailored quote, usually within 1 working day.
Frequently asked questions
Q01Is a conservatory the same as an extension under the permit rules?
Yes, a closed conservatory or garden room falls under the Bbl in the same category as a regular extension: the associated structure. The criteria for permit-free construction are the same: location in the rear garden area, maximum built-up area and maximum height. However, a conservatory is subject to additional building requirements for insulation and glass detailing because it constitutes a heated envelope.
Q02Can I build a conservatory at the rear of a corner house without a permit?
That depends on the exact location. With a corner property, the side garden area often borders publicly accessible land such as a pavement or road. A conservatory on that side garden area always requires a permit. At the strict rear of a corner property it may still fall within the rear garden area, but this is bespoke. Carry out the permit check on the Omgevingsloket for your specific plot.
Q03Does a conservatory have to meet insulation requirements even if it is permit-free?
Yes. The Bbl sets building technical requirements that always apply, even without a permit. A conservatory that is thermally part of the heated home must comply with the insulation values for glass, roof and connections. Cheap single glazing or old double glazing does not meet the standard. Always have the insulation requirements calculated and incorporate them into the drawings.
Q04Do I need a structural calculation for a conservatory?
That depends on the construction. If the conservatory has a lightweight aluminium or steel frame structure that is not connected to a load-bearing wall of the house, a formal structural calculation can sometimes be omitted. However, if you create an opening in the rear facade for a wide passage to the conservatory, a structural calculation for the steel beam is legally required, even for permit-free construction. Tekenpunt assesses this per project and connects you to our KIWA-certified structural engineer if needed.
Q05What is the difference between a conservatory and a canopy in terms of the rules?
A conservatory is an enclosed space with glazed walls and roof that forms a thermal part of the home. A canopy has a roof but no closed side walls and is in open connection with the outside air. Both fall under the Bbl as an associated structure and count towards the maximum built-up area, but a conservatory is subject to additional insulation and fire safety requirements that do not apply to a canopy.
Q06How long does it take before I receive the conservatory drawings?
The standard delivery time at Tekenpunt is around 4 weeks. If you are in a hurry, expedited handling is available with a delivery time of 1 to 2 weeks. If you are in a hurry, expedited delivery is available: +30% for delivery in 2 weeks (minimum €295) or +50% for delivery in 1 week (minimum €495), on top of the regular drawing work.
Q07What does it cost to apply for an environmental permit for a conservatory?
The add-on for applying for an environmental permit costs €500 on top of the base price for the drawings. Tekenpunt handles the complete application including submission to the municipality. We get 90% of applications through aesthetic review in one round.
Q08Can I also build my conservatory on the side of the house?
Sometimes. If the side garden area does not border publicly accessible land and starts at least 1 metre behind the front building line, it may fall within the rear garden area. For a detached or semi-detached home this is regularly the case. For a corner house the side almost always borders public land, meaning a conservatory there always requires a permit. Always verify this via the permit check on the Omgevingsloket.
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