Guide
7 min

Velux vs Dormer: Which Attic Conversion is Right for You?

The Big Decision

You’re converting your attic. But which way: Velux (windows flush with roof) or Dormer (projecting windows that create full-height space)?

This choice affects your budget, timeline, space, and whether you need planning permission. Let’s make it simple.

Cost Comparison

Velux: €15,000 - €25,000

  • 30-40% cheaper than dormer
  • No planning permission (usually)
  • 2-3 weeks construction
  • Basic space with sloped ceilings

Dormer: €25,000 - €45,000

  • 40% more usable space
  • Planning permission required (usually)
  • 4-6 weeks construction
  • Full-height standing room

Space Reality Check

Velux: In a 30m² attic, you get ~15-18m² of standing room. Sloped ceilings mean careful furniture placement. Perfect for: Single bedroom, home office, kids’ room.

Dormer: Same 30m² attic gives you ~28-30m² of full-height space. Standard furniture fits easily. Perfect for: Master suite with ensuite, full bedroom with storage.

Real example: Maria in Blackrock chose Velux for her home office. “The sloped ceilings make it cozy. I don’t feel I’m missing space—just that it’s a different kind of space.”

Planning Permission

Velux: Usually exempt—no permission, no delay, no extra cost.

Dormer: Usually required—add 8-12 weeks and €1,500-€3,000 for professional fees.

Which Should You Choose?

Go Velux If:

  • ✓ Budget is €15,000-€25,000
  • ✓ You want to start in weeks, not months
  • ✓ Your home is traditional/Victorian
  • ✓ You need a single bedroom or office

Go Dormer If:

  • ✓ You need maximum space (ensuite, storage)
  • ✓ Full-height standing room is essential
  • ✓ You’re staying 10+ years
  • ✓ Planning permission doesn’t scare you

The Hybrid Option

Best of both worlds: Dormer at rear (for ensuite), Velux at front (maintains street appearance). Cost: €22,000-€32,000.

Calculate Your Costs

See exactly what each option would cost for your specific attic:

Attic Conversion Price Estimator

10 m²2050 m²

Cost Breakdown

Base Cost (20m² × €/m²)€NaN
Estimated Total€NaN

*This is an estimate only. Final costs depend on site inspection, structural requirements, and finish specifications.

Get Expert Advice

Still unsure? We’ll visit your property, show you both options, and give you accurate quotes for each.

Step 1 of 520%

What type of house do you have?


Disclaimer: Every property is unique. Get professional advice specific to your situation.