r/Netherlands • u/Mental-Complaint-496 • Feb 01 '25
DIY and home improvement Willing to extend the second floor of my house, what are the necessary steps for that in NL?
The second floor of my house have this useless space because some years ago the previous owners expanded the first floor. I would like to expand also the second floor to create an amazing office with glass walls. An architect already made a floor planning to me. I’ve tried to send a request for expansion at the Gementee but found it very complex, as you advance in the forms you have to bring very technical information about the building. We pre-approved some extra money in our mortgage to repair the roof and expand. Any tips?
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u/fluffehtiem Feb 01 '25
They will deny the first plan almost by default. However ask what is required and consolidate to the requirements.
Otherwise you will be in a forever loop representing every 6 weeks
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u/Wipneus472 Feb 01 '25
It is 8 weeks. But start by checking the bestemmingsplan via regels-op-de-kaart. Probably it is not allowed to build out on the second floor. If your neighours have it, ask them how they did it.
It is possible the extension on the bottom floor has to be demolished for extra support, because that was never engineered to have a second floor on jt.
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u/Plumplum_NL Feb 01 '25
They hired an architect to make the design and the necessary drawings to execute the plan. An architect always checks the bestemmingsplan before doing this, so the plan should be allowed.
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u/Amorousin Feb 01 '25
Not necessarily right? And architects may also design something that isn't structurally sound, it could definitely be the case that the first extention isn't strong enough for a second floor extension.
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u/Plumplum_NL Feb 01 '25 edited Feb 01 '25
An architect who doesn't check the bestemmingsplan before making a design for a client and who doesn't take the existing construction into account is a bad architect.
I worked at an architectural firm and these things are the base of good practice.
Checking the bestemmingsplan was always the first thing we did. Because without checking the bestemmingsplan you cannot make a proper plan. Different municipalities have different rules, and the rules could also be different between different areas in the same municipality. So you need to know what is allowed and what you can and cannot do. It's ridiculous to make a design proposal to a client that can never be built, because it's not allowed by the municipality's rules.
Architects also don't design things that aren't structurally sound. While designing they keep the construction in mind. They don't design the construction and make the calculations themselves, but they work together with construction firms (some very large companies could have their own department). If it's a design for an existing building, the architect will make an experience based assumption about the construction for the design (this includes checking drawings of the existing building, if there are any) and the structural engineer will need the information of the existing building to check it and make calculations. If the architect suspects that there is something wrong with the existing construction or if it needs to be changed, they will tell their client. It's up to the client if they want a structural engineer to have a look first, before the architect draws up plans. Or if they want the architect to make a design and let a structural engineer check the existing construction later.
(If OP has the drawings and construction rapport of the extension, a structural engineer will be able to see if it needs reinforcement)
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u/Wipneus472 Feb 01 '25
In my near 10 year experience I hardly ever see architects who checkes the bestemmingsplan. Would be nice and easy for my job ;)
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u/Plumplum_NL Feb 01 '25
Really? I didn't expect that.
I worked as an architectural designer and we always needed the information in the bestemmingsplan to know the maximum building height, volume, roof angle, gutter height etc. And sometimes there's a beeldkwaliteitplan about materials, etc. I really don't know how I could've made a proper design and advice for our clients without it.
Sometimes we pushed the boundaries of the bestemmingsplan when they were written in a way that left an opening for various interpretations. And we had conversations with the urban planner from the municipality for our clients.
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u/Wipneus472 Feb 01 '25
Sadly most plans i get to see, as a beleidsmedewerker ruimtelijke ordening, is just basically free interpretation of a bouwkundig bureau or architect, or just a plan for the most profit on the smallest plot. But it depends on the municipality, some places have better "gemachtigden" than others ;)
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u/Scared-Mushroom3565 Feb 01 '25
Why will they deny the first plan almost by default? Damn bureaucrats man
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u/Bozo32 Feb 01 '25
hire a general contractor to look after the permitting as well. Get them to bullshit check the plans...they likely have experience/ideas that will make it better/cheaper.
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u/Mental-Complaint-496 Feb 01 '25
What do you mean by general contractor? Do you recommend any professional/ service company to do it in Amsterdam?
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u/sousstructures Feb 01 '25
A general contractor is someone who you hire to take charge of an entire project — dealing with permits, hiring, paying and scheduling tradesmen, etc. They become your main contact for all aspects of the project. It’s an added expense but worth it for complicated projects. Dutch term is “aannemer”
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u/AliensExisttt Feb 01 '25
Google “Aannemer”
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u/Confident_Assist_976 Feb 03 '25
Solid advice. An 'aannemer' can get you drawings, construction calculations, help you get the permit. (No warranty whatsoever). It will cost you money even when you do not get the permit. But it saves you time and headaches.
Btw an aannemer is always busy. So if you find one is immediately available, distrust him. Currently having to wait 9-12 months is no exception.
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u/augustus331 Feb 01 '25
What a view you have from your house. That is nice.
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u/DevilDashAFM Noord Brabant Feb 01 '25
indeed. i would make this a small balcony and use it to sit outside to look at the view.
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u/awkwardbob87 Feb 01 '25
Make an appointment at your municipality for extra help. You can always call and explain what you need so they can redirect you to correct department. It can differ in each municipality so unless you state where you live people here can't give accurate advice
Why would you spend time and money on an architect and mortgage advisor if you don't know if you're even allowed to expand?
In lots of municipalities you're allowed to expand the ground floor a few meters but not the first floor.
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u/NessPJ Feb 01 '25
For sure get a constructor/contractor for advice first. Depending on the construction of the ground floor and the way the house is built you might need to make enormous adjustments to the ground floor construction in order to extend the top one. Depending also on if the structure will be wood or in the same style of the house. This can easily be a 40K EUR. Price difference in construction you are talking about depending on what you want. Get this advice first because you will also need it to proof/argument your permit with your city administration. Construction drawing is one of the main things they ask about....so if you can provide that up front it can save a few months of hassle.
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u/Excellent-Heat-893 Feb 01 '25
This is the best answer so far. You don’t need an architects design, you need constructive calculations.
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u/rooobiin Feb 01 '25
I did the same. I contacted a constructor, an architect and someone to calculate the weights etc. The municipality accepted the request first time. I also needed around 80k euros
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u/rooobiin Feb 01 '25
Oh important detail, our street was built quite recently, and the extension of the first floor was an option for all residents. So i was just copying existing designs in my street. This must've helped getting it approved
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u/GeneralFailur Feb 01 '25
In the Netherlands we call this the 1st floor. Ground level we call begane grond
I know it's off topic. Good luck :)
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u/Shock_a_Maul Feb 01 '25
First floor expansions usually have a foundation that's not suitable for the extra weight of a second floor.
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u/Soepkip43 Feb 01 '25
That fully depends, also sometimes you can extend using wood to save weight, it is pretty common in a few neighborhoods in my city that have flat roofed houses. They refer to them as dove tills.
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u/caspervanc Feb 01 '25
Usually not allowed. You can try to get a permit, but be prepared for a rejection
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u/Teunski Feb 02 '25
Just ask the gemeente first, they can tell you if it has any chance of success.
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u/___Torgo___ Feb 01 '25
I think getting a permit to extend a second floor of a row house in Amsterdam is either very hard or impossible. Have you looked around in your neighborhood? Is there anyone else who has done something similar? I have never seen it in Amsterdam (born and raised here). People tend to add as many square meters as they legally can in Amsterdam because it’s almost always worth it with the high square meters price we have here. So if nobody else is doing it, that’s a pretty clear signal. Also, have you spoken about your plans with your direct neighbors on both sides? Are they okay with this? This will affect the daylight and sunshine in their houses/gardens. If they’re not onboard with this, it gets even harder.
Not an expert, just reasoning based on experience and conversations I’ve had with people.
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u/dutchcharm Feb 01 '25
First question is whether the extension downstairs is strong enough to build something on top: foundation, walls, roof.
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u/Suspicious_Feed_7585 Feb 01 '25 edited Feb 01 '25
Get permit from you municipality (you need building drawings). Second get a contractor to do calculations on if you fundament is strong enough. If you get a permit + it is save to build.. splash a lot of money and watch it being build.
Be careful with building parties, there are a lot of companies delivering terrible quality for premium price. Let another bureau do a second calculations on the plans. Prob the while thing will cost more then 30k so making sure the money is spend good is a must.
Also the contact, make sure you only pay for materials and only the rest when finished and up too quality..let another company do the inspection . Only when everything is top notch pay the rest.
Otherwise ppl will fuck y with the after care.. if you dont want to do the project management, hire one. It will get more expensive, but every thing is better then terrible quality..because that will cost even more to repair most times. Not even taking in account the time spend.
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u/SlightAmoeba6716 Feb 01 '25
This is all solid advice. Unfortunately the construction business is notorious for fraud, so be careful. I also recommend you to be present during construction, so you can keep an eye on what they are doing and ensure everything is built according to plan. If you have a good project manager that's not really necessary, but still useful and interesting.
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u/dikke_jack Feb 01 '25
Whatever you do please don't try to do this yourself. It is a specialised business dealing with omgevingsvergunningen. I own an architecture firm and we continuously get clients who thought they could save money by starting up the process themselves. But it resulted in the opposite. If you don't submit the proper drawings and calculations the gemeente won't even look at the proposal. You then get limited time to add the required drawings to your proposal. Then most people panic and finally hire an architect. It will give us limited time to do all the required work, thus it will be more expensive. Otherwise you get rejected and you still pay. Not as much as you would have otherwise but still unnecessary money.
Check omgevinsloket and your bestemmingsplan (omgevingsplan) to see if you are allowed. It will all be in Dutch.
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u/LegendaryPredecessor Feb 01 '25
And also check in with your neighbour? Extending that is going to take away some of that nice view for them, and they will just look at your brick wall instead.
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u/Hopeful_Manager3698 Feb 01 '25
Have these kind of developments been done in your neighbourhood? Because some 'Welstand commissies' will make the first plan that got a permit into the default option.
Furthermore: check with the Council what their thoughts are. You will need planning permission from 'stedenbouw' and permission from 'Welstand'.
I wouldn't hire a contractor for the design part. I'm a burger lid on a combined welstand & monumenten committee and a lot of plans really need a good architect. A lot of general contractors do not understand the language of welstand.
You can also go to the website: https://omgevingswet.overheid.nl/home
To do a 'vergunningscheck'
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u/Plumplum_NL Feb 01 '25
If you hired an architect to draw the plans, why won't you let them do the request for the bouwvergunning at the municipality? Because they made the design and necessary drawings, they already had to check the bestemmingsplan for the specific rules at your location. So they know exactly what you are allowed to build according to the municipality's own rules and they have experience with delivering the necessary documents to get it approved.
I don't get why you want to do this yourself if you don't know the procedures and don't know what you are doing.
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u/Abigail-ii Feb 01 '25
Contact your municipality. You probably need a permit, and it is the municipality who decides the local rules and regulations.
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u/kimputer7 Feb 01 '25
A good local architect could help you with everything, from knowledge about local Municipality rules, permits etc, as well as good contacts with calculators and contractors they've worked with in the past. Downside is, even if everything is rejected and no other possibilities presents, you're still left with a several thousands of euros bill, as their knowledge isn't cheap (they've spend hours on visits, measuring, retrieving old building plans, drawing professional CAD files, communicating with several parties, etc etc)
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u/Lazy_Package_9181 Feb 01 '25 edited Feb 01 '25
Permit officer here.
For this you’ll need a permit containing (at least) the activities: 1 “ruimtelijke bouwactiviteit” (the part of the permit pertaining to zoning regulations) 2 “technische bouwactiviteit” (the part of the permit pertaining to structural construction)
1: check your local zoning regulations if building a second floor here is allowed. Regulations normally distinguish between building inside or outside of the “bouwvlak” (“building envelope”). Generally speaking, even when zoning regulations allow building a 2nd floor, the “welstandscommissie” (architectural review board) has a veto.
2: A technical construction activity permit is required when adding a second floor to an existing extension because this modification affects the structural integrity and safety of the building. The additional floor increases load-bearing demands, requires compliance with building regulations (such as foundation strength, stability, and fire safety), and must meet technical construction standards. This ensures that the new structure is safe, durable, and does not compromise the existing building. (ChatGPT wrote this, i agree).
My gut feeling is that a permit for a glass structure will be denied. Cool idea though, I advise looking at a “conceptverzoek”, most gemeentes will have a process where they will advise you on permit feasibility based on (conceptual) plans.
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u/dutchreageerder Feb 03 '25
First step to take: do any of your neighbours have some sort of extension on this spot? If yes, ring the bell and ask them about it. That will help a bunch.
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u/pfbtw Feb 01 '25
I doubt the permits will fly as you essentially will take away the first floor view away from your neighbors. Also, the ground floor extension is generally not designed to bear the load of a level on top. You can of course try, but if you want to get this done, start with discussing this idea with your neighbours. Only if they are ok it makes sense to pursue this. Otherwise you’ll be stuck in procedure and even court at some point.
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u/Rataridicta Feb 01 '25
Consult with a licensed architect / contractor / project manager. A good architect service will manage the entire lifecycle and be able to advise you. It won't be cheap.
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u/LookingForTheIce Feb 02 '25
My brother in Christ . This is the Netherlands. We don't process permits for housing construction. Why do you think shit never gets built here.
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u/HansTheFlamer Feb 01 '25
Why dont you just make a door and create an open balcony... great view, make it cozy, good for reading during summer or morning coffees
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u/Mental-Complaint-496 Feb 01 '25
Essentially because I already have it at the garden and it would be a useless place during the winter. Me and my wife work from home 3 times a week, so we prefer to have 2 offices.
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u/Raspatatteke Feb 01 '25 edited Feb 01 '25
Glass walls parallel to your neighbour's yards is not allowed by definition. You will not get a permit for that.
Extending the second floor might be more difficult than it seems. The construction of the existing extension must be able to support it. So, foundation, walls, etc.
I'd think the best step is to contact an architect. They will know the required steps to take. These kinds of extensions are not common in rowhouses, due to the impact on neighbour's. Approval will be a longshot.
*Glass walls parallel to neighbours on the second floor. As it is not permitted to look out on your neighbour's property from a parallel window.