How long does it take to install a dormer?
A prefab dormer is installed in one day, sometimes in a morning. A traditionally on-site built dormer takes 3 to 5 working days. Preparation (quote, permit, production time) takes much longer: count on 8 to 16 weeks between order and installation.
Installation itself: prefab vs. traditional
A prefab dormer arrives as one element on a lorry and is craned onto the roof. Installation itself takes 4 to 8 hours. A traditionally on-site assembled dormer — building cheeks on the roof, making the cap, cladding — takes 3 to 5 working days.
Preparation time
Quote request to final order: 2 to 4 weeks. Prefab factory production: 4 to 10 weeks (depending on season and demand). Any permit procedure: 8 weeks (regular procedure). Add them up and plan well in advance — builders are often months booked up in spring and autumn.
Interior finish is separate
Many providers deliver the dormer 'trim-ready': frames, glass, roof and exterior finish complete, interior bare walls with insulation. Plastering, painting, flooring and electrical are a separate job of 1 to 2 weeks — tender separately or do it yourself.