Dormer in one day: how realistic

Factory assembly of the prefab happens weeks before your install date (3-6 weeks production). On install day: delivery on low-loader, hoisting with telescopic crane, placement onto the opening, lead and zinc junction, exterior sealing.

Then tile repair around the cheeks, rainwater downpipe hookup, and basic cleanup. By 17:00-18:00 exterior work is done and your roof is watertight again.

Interior finishing (plaster, paint, floor join) — 1-3 extra workdays, often spread over 1-2 weeks for sealant/glue curing.

Permit procedure (8-26 weeks ahead), removing the old dormer on replacement (half to full extra day), and municipal inspection if required. For optional shading, blackout or special glazing: separate fitter appointment.

Traditional timber (4-6 days build), dormers wider than 4 m (often two prefab segments, +1 day), complex roofs (composite, corner houses with double pitch).

Weather risk (rain, wind >6 Bft, frost <0°C), or when the crane must stand more than 12 m from the roof and no larger 60-80 t fits in your street.

Crane pitch within 10 m of the roof clear of obstacles (cars, trees, power lines), parking permit or restriction arranged 1-2 weeks ahead, and neighbours informed.

House access (key or person present) from 06:30 to 18:00, and at least 80 cm clear passage for material to the loft. Power and water for the crew. Without these the success rate drops from 85% to 50-60%.