01 · Challenge
Low ridge made attic uninhabitable
The property in Hilversum-Noord dated from the early post-war reconstruction period and had a compact roof structure with a ridge only 2.2 metres above the attic floor. This gave a maximum standing height of 1.5 metres in the centre, making the attic usable only as storage. The owner wanted to convert it into a proper bedroom. The municipality of Hilversum sets requirements for roof-raising projects regarding roof pitch angle and the relationship to neighbouring properties.
02 · Our approach
New roof structure with identical pitch and 40 cm higher ridge
We designed a new roof structure that respects the original roof pitch angle but raises the ridge 40 centimetres. This provided just enough standing height in the central part of the attic. The structural engineer fully recalculated the new purlins, collar ties and ridge beam. The permit application included a ridge profile comparison with the immediate neighbouring properties, so that the municipality could immediately assess that the profile did not deviate from the building line.
03 · Result
12 m² of habitable attic space with central standing height
The building permit was granted in 8 weeks. The contractor dismantled the existing roof structure and installed the new one in three working days. The attic now has 12 m² with a standing height of 2.1 metres in the central part. The property looks virtually identical from the outside: the slightly higher ridge line is barely noticeable. The owner confirmed it was one of the best renovation investments he could have made.