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Roof extension in Haarlem with dormers and new structural floor

In Haarlem, we built a roof extension with a 0.4 m increase in the 1st floor height and a new load-bearing floor for the 2nd floor. The intervention adds a full-fledged extra floor, with plenty of daylight via dormers and HR++ skylights, improved insulation and a sophisticated layout for a future bathroom.

Location:
Harlem
Duration:
9 weeks
Cost:
€116.204

Design, engineering & preparation

We started with the architectural and structural plan, including scaffolding and a phased method for demolition, structural work and dismantling. Rubbish and demolition material have been continuously removed for a safe, clean construction site.

1st floor — elevation and support structure

  • 1st floor ceiling demolished.
  • Wall increase +0.4 m: interior walls (6 m²) and outer walls (12 m²) raised for the new roofline.
  • Extra façade masonry (north): 0.4 m high strip (2 m²) adjacent to the existing façade.
  • Reinforced timber frame: additional wooden styles/beams installed to support the roof structure; parts of walls opened locally and repaired after installation.
  • Layout change: wall partially removed and bathroom door moved to make room for the new staircase.
  • New beam layers/frames according to the revised floor plan, including enclosures for stiffeners in the neighbor wall (without repair in case of breakthrough).
  • Steel lintels installed above window frames.
  • Façade insulation (inside, north): 11 m² insulated for a better thermal shell.

2nd floor structural work — floor, roof and outer shell

  • New wooden support and subfloor (35 m²) as the basis for the new floor.
  • Sloped roof with dormers (28 m²) finished with roof tiles and gutters on the north and south sides.
  • Flat roof (32 m²) installed and insulated as a hot roof structure.
  • Exterior walls (76 m²) installed; Keralit cladding applied to one end façade and to the dormers (24 m²).
  • Three new wooden frames installed and finished/painted.

Daylight & ventilation

  • Two HR++ skylights installed;
  • Two electric skylights installed;
  • Active ventilation unit prepared and installed in the (future) bathroom area.

Installations — electricity, heating and sanitation

  • Electricity: new pipes with 9 sockets, 4 switches and 4 light points.
  • Heating: 4 radiators installed with neat pipes.
  • Sanitary (roof/bathroom): new supply and exhaust pipes prepared; the open sewer connection in the attic has been checked and capped.

Interior walls & ceilings — acoustics and finishing

  • Interior walls: 41 m² of new partitions with sound-insulating padding, logically positioned for rooms and wet areas.
  • 2nd floor ceiling: plaster ceiling (32 m²) installed.
  • Plaster walls: 1st floor +0.3—0.4 m elevation strips (15 m²) and 2nd floor (82 m²) tightly finished.
  • 1st and 2nd floor ceilings: a total of 80 m² plastered and prepared for finishing.

Outcome

A future-proof roof extension that offers extra living space, more daylight and a much improved thermal shell. The combination of raised 1st floor, new load-bearing floor, dormers and HR++ skylights, and soundproof interior walls provides a quiet, light and comfortable 2nd floor - ready for further furnishing, including a fully-fledged bathroom.

After the renovation

No items found.

Before the renovation

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It was not a straightforward job due to the age of the house (1890) and the structure where a thin wall is shared with the neighbor… but the team managed it very well. Communication was excellent throughout. We could easily share updates or questions and usually received a reply within minutes, even after hours. Their online tool was another big plus — it itemized all labor and material costs, so we could make informed choices and even swap items if needed. From a budget and timing perspective, they were among the most reasonably priced companies we spoke to, with limited additional costs during the project. Importantly, they were also able to start much sooner than other contractors. We would recommend them to anyone looking for a reliable and knowledgeable partner for major building projects.

Nandi J.
Read full review on Google

Book your free online consultation and receive a detailed renovation quote (valued at €100+ by other companies)

Our renovation experts are eager to meet you and start creating your dream space. During your personal consultation, we’ll identify key issues, understand your preferences, and discuss possible limitations.

Within 7 days, you’ll receive a detailed, transparent quote

We believe in full transparency and want you to move forward with confidence. That’s why our detailed quote will include:

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Comprehensive Task Breakdown: Clear descriptions of each step in your renovation. Understand exactly what work will be done and why.

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Itemized Costs for Raw Materials: Transparent pricing for all essential building materials. No hidden fees—know exactly where every euro goes.

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Selection and Cost of Finishing Materials: Detailed options for tiles, fixtures, accessories, and more. Choose from high-quality materials that suit your budget and style.

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Labor Costs: A clear overview of all the costs for craftsmanship.

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All Additional Costs: Including permits, waste disposal, and other expenses. Full transparency to avoid surprises later.

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Design Project Costs (If Needed): A professional design package to visualize your dream bathroom.

REQUEST FREE CONSULTATION & QUOTE

Bricknest B.V., KvK 91935490, Leo Smitstraat 11-B, 1082MP, Amsterdam