Cost · Timber dormer

What does a timber dormer cost?

A timber dormer costs more upfront than PVC and prefab but is usually cheaper to maintain over decades — provided you choose the right wood and keep up the finish.

5 min leestijd·Onafhankelijke informatie

Short answer

A 3-metre timber dormer with HR++ glazing typically lands between €11,000 and €19,000 installed. Premium woods (Accoya, Western Red Cedar) and bespoke joinery push the upper end; painted softwood and standard sizes sit at the lower end.

Realistic price ranges

Painted softwood, 3 m: €11,000–€14,000.
Western Red Cedar, 3 m: €13,000–€17,000.
Accoya, 3 m: €15,000–€19,000.
Add per extra metre: €1,800–€2,800 depending on roof access and crane requirements.

What drives the price

Wood species and grade — Accoya costs roughly 2× painted pine per m².
Insulation package (Rc 4.5 minimum, Rc 6.0+ pushes price).
Glazing: HR++ baseline, triple adds €400–€800.
Lead apron and zinc detailing instead of EPDM trim.
Crane access and street closures.
Interior finish: painted MDF reveals vs hardwood-veneered.

Wood types compared

Painted softwood is the cheapest and most flexible but needs the most maintenance. Western Red Cedar is naturally durable, dimensionally stable and ages to silver-grey if left untreated. Accoya is acetylated pine — almost rot-proof, very stable, factory-coated for a 10–15 year cycle.

Lifetime cost

Over a 30-year horizon, painted softwood requires 4–6 repaint cycles (€800–€1,500 each) plus likely cladding replacement. Cedar and Accoya typically need 2–3 lighter cycles. A higher purchase price often turns into a lower total cost of ownership.

FAQ

Veelgestelde vragen

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01What does a timber dormer cost in 2026?

Indicatively €11,000–€19,000 for a 3-metre timber dormer with HR++ glazing, depending on cladding (Western Red Cedar, Accoya or painted softwood), insulation package and finish level.

02Is timber more expensive than PVC?

Yes, typically 20–35% more on initial cost, mostly due to materials and labour. Over a 30-year horizon timber can be more economical if maintained properly, because the structure outlasts most PVC cladding cycles.

03How often does a timber dormer need painting?

Painted softwood: every 5–7 years. Stained Western Red Cedar: every 8–12 years. Accoya factory-coated: every 10–15 years. Skip cycles and costs rise sharply.

Conclusie

Timber rewards a longer planning horizon. If you only look at the purchase price, PVC wins; if you look at the next 30 years on the same house, timber with the right wood often comes out ahead.