Prefab dormer
Built in a factory to your measurements and lifted in with a crane in one day. The fastest and most affordable option for a standard roof, in plastic or with a wood-look finish.
A dormer window for more space and light in your attic
Dormer windows across Brabant, in English.A dormer (in Dutch: dakkapel) turns a sloping attic into a room you can stand up in. Prefab or made to measure, usually weathertight in one day, and finished inside by the same team. We check whether you need a permit before anything is ordered.
22 years
in the trade
250+
projects delivered
CO-keur certified
STEK registered
NEN 1010 electrical
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VCA safety certifiedCO-keur certifiedSTEK registeredNEN 1010 electricalGPI certifiedVCA safety certifiedCO-keur certifiedSTEK registeredNEN 1010 electricalGPI certifiedVCA safety certifiedStanding height and daylight
where you had a sloping roof
Most Dutch houses with a pitched roof have an attic that is only usable in the middle. A dormer window pushes the roof out on one side, so you get full standing height over a large part of the floor and a proper window. That is the difference between a storage attic and a third bedroom, a home office or a room for a growing family.
At Boers & Breuer Totaalbouw we fit prefab dormers, which are made in a factory and placed in one working day, and dormers built on site to measure, when the roof, the width or the local rules ask for it. Either way, our own team does the finishing inside: insulation, plasterboard, sockets, lighting and, if you want, a radiator connection.
We fit dormers in Eindhoven, Veldhoven, Den Bosch, Tilburg, Breda and Helmond. Joeri Boers is your contact from the first visit to the finished room, in English.
Often weathertight in a day
A prefab dormer is lifted in and closed on the same day.
Prefab or made to measure
Factory-made for speed, or built on site when the roof asks for it.
Permit check included
We check the rules for your roof before anything is ordered.
Finished inside by us
Insulation, plasterboard, electrics and heating by the same team.
How we fit your dormer
Four steps, from the first measurement to a finished room.
1
Visit & measuring
Joeri looks at the roof, the rafters and the attic, measures up and talks through width, windows and finish with you.
2
Permit & order
We check whether the dormer is permit-free on your roof. If not, we apply for the permit. Then we order the prefab dormer or prepare the build on site.
3
Fitting day
The roof is opened, the trimmer is placed and the dormer goes in. A prefab dormer is weathertight the same day. Made to measure takes one to two weeks on the roof.
4
Inside finish
Insulation, plasterboard, filling, window sills, sockets and lighting. We leave the room ready for painting, or painted if you prefer.
What our clients say
Most of our reviews are written in Dutch. Your browser can translate them in one click.
Recent work by our team
A few recent jobs on roofs and attics by our own team.
Dormer window
A dormer fitted, finished and insulated, with the inside ready for plastering.
Roof extension, Waspik
A new roof structure and an extra floor on a farmhouse, built by our own team.
Full renovation, Waalwijk
Complete finish of a villa: herringbone floor, open kitchen and sliding doors to the garden.
Which dormer suits your roof?
Four common options. The width, the roof and the local rules decide which one makes sense.
Made-to-measure dormer
Built on site from timber, so you are free in width, window layout and materials. The right choice when the house has a specific style or the municipality sets requirements.
Wide dormer
Four to six metres, across the whole attic or over two rooms. It needs a heavier trimmer in the roof and sometimes extra support, which we calculate beforehand.
Two dormers at once
Front and back in one go. One scaffold, one crane and one round of disruption, so cheaper than two separate projects.
What does a dormer window cost?
Guide prices for a dormer fitted and finished on the outside, including trimming the roof, flashing and cladding. The inside finish (insulation, plasterboard, electrics) depends on your attic and is itemised separately in your quote.
Prefab dormer up to 2.5 metres
Made in a factory and fitted in one working day. Enough for light and standing height in one bedroom or a work space.
Fully finished
€6,500 to €9,500
Made to measure, 3 to 3.5 metres
Built on site, so free in layout, windows and materials. Fits an existing facade or a specific local requirement.
Fully finished
€10,000 to €15,000
Wide dormer, 4 to 6 metres
Across the full width of the attic or over two rooms. Needs a heavier trimmer and sometimes extra support.
Fully finished
€15,000 to €24,000
Two dormers in one go
Front and back at the same time. One scaffold, one crane, one round of disruption.
Fully finished
€18,000 to €32,000
| Prefab up to 2.5 m | Made to measure 3 to 3.5 m | Wide 4 to 6 m | Two dormers | |
|---|---|---|---|---|
| Guide price | €6,500 to €9,500 | €10,000 to €15,000 | €15,000 to €24,000 | €18,000 to €32,000 |
| Time on the roof | 1 day | 1 to 2 weeks | 1 to 2 weeks | 2 to 3 weeks |
| Freedom in design | Limited | Full | Full | Full |
| Permit | Often not at the back | Depends on location | Often needed | Front almost always |
| Structural calculation | Rarely | Sometimes | Usually | Per dormer |
Why we check the rafters first
A dormer is placed in a hole in your roof, and the rafters you cut through carry part of that roof. They are replaced by a trimmer that takes the load to the rafters next to it. On a wide dormer or an older roof, that is where it can go wrong. We check the roof structure at the first visit, and if needed a structural engineer calculates the trimmer before the dormer is ordered.
- Rafters and purlins checked for size, condition and woodworm
- Trimmer sized for the width of the dormer
- Insulation of the cheeks and roof of the dormer to current standards
- Lead or EPDM flashing that runs properly under the roof tiles
- Ventilation above the insulation to prevent condensation
- Inside connection between old roof and dormer without a draught
Dormer rules you should know
What decides whether you need a permit, and what we arrange for you.
Back roof: often permit-free
A dormer on the rear roof slope is often permit-free, as long as it stays within set limits: not too high, set back from the roof edges and the ridge, and not on a listed building. We check your roof against those limits before ordering.
Front roof: usually a permit
A dormer on the street side, or on the side facing a public road, almost always needs a permit (omgevingsvergunning), and the municipality looks at how it fits the street. Plan six to eight weeks for that decision.
Terraces and neighbours
In a row of houses, a dormer that matches the neighbours' dormers is approved much more easily. If your neighbour already has one, we often use the same width and height. Some streets in Eindhoven and Den Bosch have their own style rules.
Where a dormer goes wrong
Four mistakes we see on attics, and how we prevent them.
1
Ordered before the permit check
A prefab dormer that turns out to need a permit waits in a warehouse for two months. Or worse, it goes on the roof and the municipality asks for it to come off. Check first, order second.
2
A cold, damp attic room
The dormer itself is insulated, but the sloping roof next to it is not. Then the new room is cold in winter and gets condensation in the corners. Insulating the rest of the roof at the same time is usually worth it.
3
A trimmer that is too light
On a wide dormer, the rafters next to the opening carry a lot more than before. A trimmer that is too light causes the roof to sag over the years. We size it for your width, with a calculation where needed.
4
No room for the stairs
A dormer gives you height, but you also need to get up there safely. A fixed staircase takes space on the floor below. We look at where the stairs can go before you decide on the dormer.
Dormers across Brabant
The roofs and the rules differ per city. This is what we come across.
Eindhoven
Pitched roofs on 1930s houses in Stratum and Gestel, and post-war terraces in Woensel where half the street already has a dormer. In Philipsdorp stricter heritage rules apply. More about Eindhoven.
Veldhoven
1970s and 1980s family homes with an attic that is ready for a third or fourth bedroom. Usually a straightforward rear dormer. More about Veldhoven.
Den Bosch
In the protected city centre, dormers are checked closely for style and size. In Maaspoort and Rosmalen they are often permit-free at the back. More about Den Bosch.
Tilburg
1930s houses in Oud-Zuid and 1980s homes in the Reeshof. In the Reeshof many streets have matching dormers, which makes approval easy. More about Tilburg.
Breda
Characterful roofs in Ginneken and Belcrum where a made-to-measure dormer fits better than prefab, and terraces in the Haagse Beemden. More about Breda.
Helmond
Newer houses in Brandevoort, where the neighbourhood's traditional style has its own rules, and standard family homes in Dierdonk and Stiphout. More about Helmond.
Often combined with this
Work that goes well together with a dormer window.
Roof extension
Need more than one room? A roof extension gives you a whole extra floor.
Read more
Full home renovation
Combining the attic with a bigger renovation saves a second round of scaffolding.
Read more
Bathroom renovation
A second bathroom in the attic? We check the drainage and floor before you plan it.
Read moreFrequently asked questions about dormer window
Answers to the questions we are asked most, in plain English.
A prefab dormer up to 2.5 metres costs €6,500 to €9,500. A made-to-measure dormer of 3 to 3.5 metres costs €10,000 to €15,000, a wide dormer of 4 to 6 metres €15,000 to €24,000, and two dormers at once €18,000 to €32,000. These are for the dormer fitted and finished on the outside. The inside finish depends on your attic and is itemised in your quote.
On the rear roof slope often not, if it stays within the national limits for height and distance to the roof edges and the building is not listed. On the front or on a side facing the street, almost always yes. We check it for your roof before ordering and handle the application if needed.
A prefab dormer is lifted in and weathertight in one working day. A made-to-measure dormer takes one to two weeks on the roof. The inside finish takes a few days to a week. If a permit is needed, the municipality usually decides within eight weeks.
No, it is made differently. A prefab dormer is built in a factory under controlled conditions and is very well suited to standard roofs. Made to measure is better when the width, the roof shape or the style of the house needs something specific.
Yes. The attic is opened for a few hours and closed again the same day. We protect the stairs and the floor below against dust and clean up before we leave.
For a small dormer on a sound roof usually not. For a wide dormer, an older roof or when rafters show damage, yes. We decide that at the first visit and arrange the calculation if needed.
Prefab dormers usually have plastic cladding, available in wood-look finishes and in the colour of your frames. Made-to-measure dormers can be clad in timber, zinc or composite panels. The frames are plastic, timber or aluminium, with HR++ or triple glazing.
Yes, and it is often worth doing at the same time. An insulated dormer next to an uninsulated roof still leaves you with a cold room. Roof insulation can qualify for the ISDE subsidy when combined with another measure.
Sometimes. A dormer with doors to a small balcony almost always needs a permit and extra attention to the structure and to privacy for the neighbours. We tell you at the visit whether it is realistic for your roof.
We can. Often a loft ladder is replaced by a fixed staircase when the attic becomes a real room. That takes space on the floor below, so we plan the stairs together with the dormer.
Yes, across Noord-Brabant, including Eindhoven, Veldhoven, Best, Son en Breugel, Nuenen, Waalre, Helmond, Den Bosch, Tilburg and Breda, from our base in Waalwijk.
A dormer gives you standing height on one side of the attic, usually for one room. A roof extension replaces or raises the roof and gives you a complete extra floor. Our guide dormer, roof extension or home extension compares the options.
Good to know about a dormer window
A dormer is the fastest way to turn an attic into a usable room. A prefab dormer costs €6,500 to €9,500 and is weathertight in one day, a made-to-measure dormer €10,000 to €15,000. The width decides a lot: from about four metres, the trimmer in the roof becomes heavier and a structural calculation becomes likely.
Most of the work that makes a dormer last is invisible: a trimmer sized for the opening, flashing that runs properly under the tiles, insulation to current standards and ventilation above it. On the inside, the connection between the old roof and the dormer is where draughts appear if it is not done carefully.
We fit dormers for English-speaking clients in Eindhoven, Veldhoven, Best, Nuenen, Helmond, Den Bosch, Tilburg and Breda. You will see the Dutch word dakkapel on quotes and permits. Our guide to Dutch renovation terms explains that and the other words you will come across.
Ready for your dormer?
Book a no-obligation visit. Joeri looks at your roof and attic, tells you which dormer fits and whether you need a permit, and sends a quote in English.
✓ Joeri contacts you personally to talk through your plans
✓ A no-obligation visit at your home
✓ Honest advice, in English, no sales talk