A full extra storey on top of a flat roof. The largest floor-area gain of all roof types and maximum increase in residential value. A permit and structural check are always required. We handle everything from drawing to handover-ready.
Adding storeys is a full extra storey on top of a flat roof, over the whole footprint of the home or complex. A permit-ready drawing costs from €649 incl. VAT and we plan it by arrangement; rush is available for a surcharge. An environmental permit is always required. You follow your entire application live in your own online file, from quote to delivery.
Adding a storey means building a full additional floor on an existing flat roof, across the entire footprint of the home or complex. This is fundamentally different from a roof extension (extra space on a pitched roof) or a dormer (a projection in the pitched roof surface). Below are the elements that always require attention when adding a storey.
The first check: can the existing load-bearing walls, floor joists and foundation support the additional load? We establish this with a structural calculation. No permit application starts without its approval.
The floor of the new storey rests on the existing walls or on additional steel profiles. Thickness and reinforcement details are determined in consultation with the structural engineer.
Light steel frame or masonry, depending on the load-bearing capacity. Insulation values must meet the current Building Decree requirements (Rc ≥ 4.7 for walls).
The junction between the new facade and the existing exterior wall is a cold bridge risk. We detail this carefully in the drawing.
The top closure of the additional storey, flat or with a shallow pitch. Including roof edge, drainage and roof insulation (Rc ≥ 6.3).
Access to the new floor requires space on the existing storey. We determine the position and width of the staircase early in the design process.
Adding a storey significantly alters height and silhouette. A building permit is always required. Four questions to estimate the complexity.
Adding a storey always requires a building permit with an aesthetic review. In addition, a structural calculation is necessary to confirm that the existing structure can handle the extra load. For a flat-roof terraced house with 1 extra storey, this is achievable in most cases. We assess your situation free of charge and draw up a fixed-price quote.
Indicative calculator for design and permit. Construction is carried out separately by a contractor.
Lines excl. VAT
* We handle design, building permit and (if desired) structural calculation. Construction is carried out separately by a contractor; build costs are an indication based on approximately €2,200 per m² for adding a storey. Request a quote for exact drawing costs.
Amounts shown are incl. VAT (consumer price); the amount below the total is the amount without VAT. Your personal quote always shows the exact total price.Amounts shown are excl. VAT; the amount below the total is the amount incl. VAT (consumer price). Your personal quote always shows the exact total price.
Every package includes the drawing. Add structural calculation or the full permit route.
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From a single extra storey on a terraced house to multiple storeys added to an apartment block. We advise on what is structurally and planning-wise feasible.
The most requested type of adding a storey: a full extra floor on top of a flat-roof terraced house. +30 to +50 m², always including building permit and structural calculation.
Two extra storeys on a flat or gallery-access building. Owners' association approval required, more extensive foundation investigation. Significant area gain for the entire complex.
A combination of adding a storey and a larger footprint on the new level, or merging neighbouring roofs. Maximum floor-area gain, the most complex process.
Adding a storey yields the most m² but places the highest demands on structure and foundations. Here is the full comparison against the alternatives.
The complexity of adding a storey depends greatly on the type of building, the construction period and the local aesthetic review requirements. A few typical scenarios.
Example project · adding a storey 1 floor · post-war home · +45 m²
Challenge: A family in Rotterdam had a post-war flat-roof terraced house (built 1962) and wanted to expand without moving. The property already had a rear extension. Adding a storey was the only option to create a full additional bedroom floor.
Our approach: We started with a structural pre-scan: wall thickness, floor span and an estimate of the foundation. The outcome was positive. We then produced the architectural drawings for the building permit, including the facade connection, roof waterproofing and insulation details. The structural engineer worked out the calculation in parallel.
Result: 45 m² of extra living space on the new floor, existing layout below left untouched. Permit granted in 8 weeks, construction completed in 10 weeks. Property value estimated to have risen by approximately 15%.
Adding a storey is a significant investment with a high return. What you still need to know about financing, homeowners association approval and sustainability requirements.
Adding a storey significantly alters the height and street profile of a building. A building permit with aesthetic review is always required. We handle the application in full, including drawings and supporting documentation.
SOURCE · ENVIRONMENT ACT 2026 / BblAdding a storey increases the property value significantly and can be co-financed through a renovation mortgage (NHG up to 106% of the value after renovation) or a building deposit at your bank.
BRON · NHG.NL 2026For an apartment block, written consent from the owners association (VvE) is required in addition to the building permit. The deed of division determines who becomes the owner of the new storey. We advise on the procedural steps.
ADVICE · CONSULT OWNERS' ASSOCIATION BEFORE STARTYes, always. An additional storey substantially changes the height and profile of the building. A building permit with aesthetic review is always required. We handle the full application, including all required drawings and supporting documentation.
A permit-ready drawing for an extra storey on a terraced house starts from €649 incl. VAT. The price depends on the floor area of the new level, the type of building and the complexity of the connection to the existing structure. We always prepare a no-obligation fixed-price quote.
We establish this through a structural calculation. The existing load-bearing walls, floor beams and foundation must be able to handle the additional load. For most post-war flat-roof terraced houses adding a storey is structurally feasible, but it varies by construction period and soil type. A structural calculation is almost always required when adding a storey.
Adding a storey is a full extra level on top of a flat roof, covering the entire footprint of the home or building. A roof extension is an addition or extra floor on an existing pitched roof. Adding a storey yields the most square metres but places greater demands on the load-bearing structure and the foundations.
We plan the drawing by arrangement; rush is available for a surcharge. The municipal decision period for the environmental permit is 8 weeks.
Yes. We provide roof-raising drawings and permit procedures throughout the Netherlands. We do the drawing work remotely; we submit the permit to your municipality. We work from Amsterdam, remotely throughout the Netherlands, with clients from Groningen to Zeeland.
13 clients rated their added storey project with an average of 4,8 out of 5 stars. A few of their comments:
We needed drawings quickly for our added storey in Amsterdam. Tekenpunt handled this fantastically. The environmental permit went through first time.
Adding a storeyFantastic experience. We urgently needed a structural calculation for an added storey. We had the documents in no time, and the municipality of Hoorn approved without any problems. The price was very clear upfront, no surprises afterwards.
Adding a storeyGreat help with the permit application for the added storey. The municipality of Alkmaar had a few questions about the aesthetic review, but they were resolved quickly.
Adding a storeyAfter some searching we ended up at Tekenpunt for our added storey. What a relief! They know the rules in Helmond well. The whole process, from first sketch to approved permit, went smoothly. Our contractor was also full of praise for the quality of the drawings.
Adding a storeyA fixed-price quote as soon as possible. Free structural pre-scan of your situation. No obligation.