Frequently asked questions about dormers
Each page answers one concrete question in 300-700 words and links to the comprehensive guide for the full picture. No quotes, no sales — just clear information.
- 4 min
What does a 3-metre dormer cost?
A 3-metre dormer costs as an indicative range €6,000 to €9,000 including installation and VAT. The spread is driven by material choice (PVC, wood, aluminium), glass (HR++ or triple), insulation thickness, roof pitch, roof height (crane accessibility) and how much interior finish is included. Get at least three quotes and compare line items — not just totals.
Read answer - 4 min
What does a 4-metre dormer cost?
A 4-metre dormer costs as an indicative range €7,000 to €10,000 including installation and VAT. Two or three frames, more living space than a 3-metre — but the price does not scale linearly: extra glass, wider structure and heavier trimmer make it relatively more expensive than 'one extra metre'. Roof pitch and height affect accessibility and thereby the install price.
Read answer - 4 min
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.
Read answer - 3 min
How much VAT applies to a dormer?
The standard rate is 21% VAT on materials and labour. For homes older than 2 years a reduced rate of 9% applies on the labour hours (not on materials) — this falls under the regulation for renovation and repair of existing dwellings. Ask the builder to itemise VAT on the invoice.
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- 3 min
How wide may a dormer be?
For a permit-free dormer on the rear roof plane, the Dutch Building Decree (Bbl) does not prescribe a maximum width, but it does require: at least 0.5 m clearance to the sides, ridge and gutter. In practice your roof plane determines the maximum width. The front roof plane always requires a planning permit and is subject to local welstand rules.
Read answer - 3 min
What does a dormer planning permit cost?
Municipal fees for an omgevingsvergunning (planning permit) for a dormer are indicatively €300–€700, depending on the municipality. That covers only processing; drawings and any structural advice are extra. On the rear roof plane a dormer is often permit-free — then there are no fees.
Read answer - 3 min
What does a ridge-raising permit cost?
For a ridge raising there are three cost items: drafting (architect or drawing bureau) indicatively €300–€1,200, structural calculation €600–€1,000, and municipal fees (variable, depending on construction sum). A ridge raising is almost never permit-free because the roofline changes.
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- 3 min
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.
Read answer - 4 min
What to look out for when buying a dormer?
The four most important points: 1) check the provider supplies an itemised quote with every line listed separately, 2) request three quotes to compare fairly, 3) check whether insulation, ventilation and finish are included, and 4) read references or visit a sample project.
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