What does a 5-metre dormer cost?
A 5-metre dormer costs as an indicative range €8,000 to €11,000 including installation and VAT. A significant intervention, usually with three frames. Besides the material premium, structural changes to the roof may be needed. Roof pitch and height determine whether a crane is required — which affects the final amount.
Structural considerations
From 5 metres the trimmer span becomes a design question, not a routine job. A structural engineer often has to produce calculations for the joists and couplings, because the roof above the dormer bears on the cheeks and trimmer. This is sometimes included and sometimes not — ask.
Planning permission at 5 metres
Permit-free on the rear roof plane provided all conditions are met (see /vergunning/dakkapel-achterkant). On some roof planes 5 metres is too wide to keep the minimum 0.5 m clearance to the sides — then an omgevingsvergunning is required. Measure your roof plane before committing to a width.
Material choice strongly affects the premium
At 5 metres the absolute euro difference between PVC and wood, or HR++ vs. triple glass, is larger than at 3 metres. Choose deliberately: a wooden frame requires maintenance but looks more traditional, PVC is low-maintenance. Triple glass only adds value in a well-insulated home.