Balcony Inspection

A balcony hangs on the outside of the house. It takes all the rain and frost, and what holds it up is usually out of sight: steel beams built into the facade, reinforcement inside the concrete, timber joists behind a sheet of plywood. That is exactly where things start to go wrong.

On this page you can read what we find on balconies, how to recognise the first signs, when it becomes dangerous, what repairs cost and what to watch for as a buyer or owners’ association (VvE). Everything is based on our own reports.

Nederlandse versie: Kennisbank Balkoninspectie. Reviews from English-speaking clients: English reviews.

In brief

Water is almost always where it starts. A top surface that isn’t watertight, a poor connection to the facade or a leaking drain. Rust, concrete rot or wood rot follow.
The load-bearing part is often hidden. On many old Amsterdam balconies the concrete rests on steel beams that are partly built into the facade. From outside you only see half of them.
Rust in the facade is a warning sign. Rusting steel expands. It pushes brickwork outwards and can make concrete spall.
A loose or low balustrade is an immediate fall risk, especially with small children.
A balcony inspection at Premiumkeur costs from € 699 including VAT, also when there are several balconies.

1. Balconies in Amsterdam and beyond

In our reports we see three types of balcony again and again, in Amsterdam and just as much in Haarlem, Utrecht, the Gooi area or Alkmaar. The way they were built was similar across the Netherlands, and so are the problems.

Concrete balconies on steel beams. Typical of the housing built in the 1920s and 1930s, in Amsterdam for example in West, Zuid and Oost. A concrete slab rests on steel H-beams built into the facade, often with a steel U or C section at the front. The railing is fixed to that section or drilled through the concrete.
Timber balconies. A timber structure with a floor of plywood, boards or composite decking. Often added later, for example on the roof of an extension.
Stone and steel balconies in older buildings. Bluestone slabs on steel brackets, or a steel balcony with timber floorboards, in buildings from around 1900.

The same applies to all three: the structure was made at a time when nobody counted on eighty or a hundred years of rain. What was good enough then is now often due for replacement or major maintenance.

With an apartment, the balcony is a common part in many deeds of division (splitsingsakte), even if only you use it. In that case the owners’ association decides and pays. Check the deed of division and the regulations to see how it is arranged in your building.

2. What we find on balconies

For this page we read 94 of our own reports from 2018 up to and including 2026 in which we actually assessed a balcony, roof terrace or balcony railing. Seventeen of them are separate balcony inspections. The rest are pre-purchase inspections, long-term maintenance plans, and roof and damp investigations. 64 reports are about Amsterdam, the others about places such as Haarlem, Utrecht, Hilversum, Bussum, Naarden, Weesp, Alkmaar and The Hague. The balconies and the defects are very much alike. Of the buildings whose year of construction we know, more than seven in ten date from before 1940.

What we found or suspected, rounded:

A top surface or connection that isn’t watertight, or a leak into the home below: in almost half.
Old or badly fitted roofing, lead or zinc on the balcony: in more than a third.
Concrete rot (betonrot): in almost one in three.
Rusting steel beams, sections or anchors: in about a quarter.
Wood rot in the floor, joists or railing: in almost one in five.
Advice to prop the balcony, to stop using it, or a risk of collapse that could not be ruled out: in about one in five.
A railing that is loose, rusted, or that small children can climb over or through: in about one in six.

A note. You usually ask for a separate balcony inspection when something already seems wrong. In those reports we advised propping the balcony or not using it for now in about half the cases. So this doesn’t mean that half of all balconies are unsafe. It does mean that the problem, if there is one, is often bigger than it looks from the outside.

3. Signs you can see yourself

Rust stains or brown streaks on the underside or front of the balcony. Often the reinforcement or the steel behind it is rusting.
Crumbled concrete or pieces that have fallen down, with rusty reinforcing steel showing.
Cracks in the brickwork around the point where the balcony enters the facade. A rusting beam pushes the bricks outwards.
Peeling paint or plaster on the underside. Usually water is coming through the balcony.
Green deposits and damp patches on the facade or in the ceiling of the room below the balcony.
A balcony that slopes, feels springy or sags. Or a balcony door that suddenly starts to stick.
A railing that moves when you lean against it.
Standing water because the drain is too small or blocked, or because the slope is wrong.

If you see one of these signs, don’t start pulling at the balcony or jumping on it to test it. Have it looked at.

4. How it goes wrong

Concrete rot

Water gets into the concrete through small cracks. The steel inside starts to rust, expands and breaks the concrete from the inside. In Dutch this is called betonrot. In our reports the water often came in at a spot you wouldn’t expect: a railing drilled through the concrete, a hole for the downpipe, an old repair that has cracked, a gap between two balconies.

Rusting steel beams in the facade

With many balconies from the 1920s and 1930s, the real risk lies in the steel beams in the facade. Water runs between the concrete and the steel section and stays there. From outside you only see a rust line and some cracked brickwork. How far the damage goes only becomes clear when the brickwork around the beam is removed. In our report we then write that destructive investigation is needed.

Wood rot

With timber balconies we saw the same mistakes again and again: joists screwed flat against the facade so the water can’t run off, gaps between plywood sheets, and wood of lower quality. A timber floor can look reasonable from above while the joists underneath have already gone soft.

Water running into the home below

For the home below, a balcony is often a roof. If it isn’t watertight, a leak appears above the window frame or in the ceiling. With a concrete balcony, condensation can play a part too: the concrete runs through the facade to the inside and gets cold in winter. That causes damp and mould on the inside.

The neighbours’ balcony

In old buildings, the balconies of two neighbours often rest on the same steel beam, or are linked to each other. What happens next door then affects your balcony too. We saw a case where a subsided rear facade pulled several balconies down with it through that link (case 2).

That this is not theory is clear from the news as well. In Oudenbosch balconies collapsed in 2021; according to the experts Omroep Brabant spoke to, it was rusted steel in the concrete (Omroep Brabant, 2 September 2021, in Dutch). In Zeist, a periodic check in 2025 showed that the reinforcement of balconies and walkways in two blocks of flats was insufficient (NOS, 18 November 2025, in Dutch).

5. The balcony railing and the rules

If a balcony is more than 1 metre above the ground or a lower floor, it needs a barrier. For new buildings, the Dutch Building Works (Living Environment) Decree (Besluit bouwwerken leefomgeving, Bbl) sets requirements including these:

A height of at least 1 metre, and 1.2 metres if the height difference is more than 13 metres.
In the bottom 0.7 metres, openings in a home may be no wider than 0.1 metres.
Between 0.2 and 0.7 metres high, the railing may have no footholds a child could climb on.

Source: IPLO, barriers for floors, stairs and ramps: rules for new buildings (in Dutch).

Lower requirements apply to existing buildings, and an old railing doesn’t simply have to be replaced. Even so, we use the new-build figures as our safety benchmark. In our reports we wrote several times that small children could climb over or through a railing. That can often be solved for little money, for example by closing in the railing.

What we came across in railings: railings held only by a few rusted screws, a home-made railing, railings standing loose on the roofing, and a railing fixed into a bluestone balcony slab so that the slab cracked at the drill holes.

6. Renovation, coating and quotes: what to watch for

There are many good contractors and specialists. Still, in our reports we regularly see balconies that are no better after a renovation or repair. A few things to watch for:

A coating on a rotten balcony. A watertight coating can protect a sound concrete balcony well. Applied over rusting steel or loose concrete it doesn’t help; then the problem is just covered up. In one of our reports we advised against epoxy because it would not last there, and recommended zinc instead.
Painting over rust. We saw rusting steel that had only been painted over without being properly de-rusted first. Then the rust is back within a few years.
A renovation that nobody checks. For an owners’ association we checked a balcony renovation that had just been finished. The balconies turned out to be life-threatening (case 3). Have large balcony projects checked independently, preferably before the last instalment is paid.
A free inspection by the company that also does the repairs. The cost is earned back through the work that follows. That makes the advice harder to check. If someone approaches you at the door, don’t sign straight away; see your rights with doorstep selling (Rijksoverheid, in Dutch).
Guarantee. Ask what is guaranteed and for how long. In our reports we advised asking for at least ten years’ guarantee on a new balcony.

Premiumkeur does not carry out repairs and does not recommend contractors. That means we can tell you what is going on with the balcony without a stake in it.

7. How our balcony inspection works

Top surface: floor, slope, roofing or zinc, lead, the connection to the facade and the balcony door, rainwater drainage.
Underside and front: cracks, spalled concrete, rust, peeling paint or plaster, damp patches.
Structure: as far as visible, the steel beams, sections, brackets or timber joists, and the brickwork around them.
Railing: fixing, height, openings and whether a child can climb it.
The home below: where possible we look at the ceiling or the window frame under the balcony. Where needed we measure moisture.
Report with photos, a condition score per part, what has to be done now, what can wait, and an indication of the costs.

To be fair: an inspection without opening anything up remains a visual inspection. A steel beam inside the facade can’t be seen completely. If we have doubts about the structure, we say so and advise destructive investigation or a structural engineer. If there is danger, we advise propping the balcony or not using it right away, and we report it immediately.

A balcony inspection at Premiumkeur costs from € 699 including VAT, also when there are several balconies. More about the service on the page balkon inspectie Amsterdam (in Dutch). If it is mainly about concrete, see also betonrot inspectie (concrete rot inspection, in Dutch).

8. What repairs cost

Examples from our reports. The amounts are as they were in the report, including VAT, at the price level of the year of the report (2018 up to and including 2026).

Fixing a loose balcony railing properly: from about € 125.
Renewing lead, zinc or roofing on a balcony: usually € 600 to € 1,500, and € 4,000 or more when the roofing of several balconies is worn out.
A new balcony railing: about € 2,500 to € 3,000.
Completely renewing a timber balcony: about € 6,000.
Concrete balconies with a rusting steel structure in an owners’ association: about € 4,000 to € 10,000 for one or two balconies, and € 28,900 to € 50,000 for a whole facade with several balconies.

Price factors are the number of balconies, the height (scaffolding or aerial platform), whether the steel structure can be repaired or has to be replaced, and what turns up once things are opened up. Costs for scaffolding and propping often come on top. In an owners’ association the costs are usually shared among the members in proportion to their shares.

9. Case studies from our reports

Twelve balconies and roof terraces from our reports. Addresses and names have been left out.

Case 1: steel sections pushing the facade outwards, Amsterdam-Centrum

Situation. An owners’ association, four-storey building from 1954, spring 2022. Concrete balconies at the rear, carried by steel sections in the facade.

Findings. The load-bearing steel U sections and H-beams were badly affected by rust. The rusting steel was pushing the brickwork outwards. Earlier repairs had not solved this. Large chunks of brickwork could fall down.

Advice. Put a steel net around the brickwork immediately, warn the neighbours, prop the balconies with steel screw props and have a destructive investigation done. Estimated cost € 30,000 to € 50,000.

Why it matters. The danger here was not only in the balcony, but also in what could fall out of it.

Case 2: balconies pulling each other down, Amsterdam-West

Situation. An owners’ association, building from 1926, May 2020. Heavy concrete balconies on a steel H-beam and C sections, all balconies linked with steel strips.

Findings. The rear facade on one side had subsided. The balcony slabs had gone down with it and, through the linking strips, had pulled other balconies down too. One concrete balcony floor was broken and the H-beam was badly rusted. Earlier waterproofing had been done poorly.

Advice. Prop immediately. Have the balconies of both buildings structurally disconnected, but only according to a structural engineer, because disconnecting them without changes can itself create an unsafe situation.

Why it matters. A balcony is not separate from the rest of the building. Foundation, facade and neighbouring balconies are part of it.

Case 3: a renovation that had just been finished, Oud-West

Situation. An owners’ association, building from 1906, December 2024. Check of six timber balconies that a contractor had renovated shortly before.

Findings. Wood rot in the joists had not been repaired. Joints had been made too weak, trimmer beams were missing or not properly fixed, and ordinary galvanised screws had been used instead of stainless steel coach bolts. The composite boards sagged and were not watertight. One balcony structure had sagged so far that the window frame was no longer square.

Advice. Don’t use the balconies, call in a structural engineer, have the balconies rebuilt and give the contractor formal notice of default.

Why it matters. New is not the same as good. An independent check after the renovation may have prevented an accident here.

Case 4: replacing the steel for the whole facade, Amsterdam-West

Situation. An owners’ association, five-storey building from 1927, February 2020.

Findings. The steel structure of the balconies was badly affected. Rainwater got between the steel beam and the concrete, with concrete rot in several places. The facade had cracked because the built-in beam had started to rust. Roofing from the extension had been stuck against the balcony and was not watertight.

Advice. Prop the balconies and replace the steel beams at the front with galvanised beams, de-rust and where needed strengthen the H-beams, and have the concrete rot repaired. Estimated cost about € 40,000.

Why it matters. A crack in the facade above or next to a balcony can be a rusting beam.

Case 5: a railing drilled through the concrete, Rivierenbuurt

Situation. An owners’ association, building from 1930, May 2022.

Findings. The steel H sections were badly rusted and the U sections at the front were finished. There was concrete rot and the top surface had cracks. The balcony railing had been drilled through the concrete slab, which let water into the concrete there. The aluminium railing itself was still good.

Advice. Have the H sections repaired, renew the U sections in galvanised steel, sandblast, repair the concrete rot and make the top surface watertight again. Prop all balconies during the work. Short-term costs € 28,900 in total.

Why it matters. What is good doesn’t have to go. The railing could probably be reused.

Case 6: bluestone balconies and falling mortar, Amsterdam-Oost

Situation. An owners’ association, building from 1894, September 2022. Bluestone balcony slabs with a galvanised railing, partly on the original steel structure and partly on concrete added later.

Findings. The railing had been fixed into the bluestone. Water in the drill holes made the slab crack, with salt efflorescence; in frost a slab like that can break. Repairs with sand-cement mortar had not bonded and could fall on passers-by. The connection to the facade and window frames was not watertight.

Advice. Prop the balcony on the second floor immediately and stop using it, remove loose mortar and have the structure investigated further.

Why it matters. Even a balcony that looks solid can weaken at exactly the point where the railing is fixed.

Case 7: timber balconies that are better rebuilt, Oud-West

Situation. A five-storey building from 1888, May 2020. Timber balconies with plywood floors.

Findings. Wood rot in the structure, the floor and the railing. The joists had been screwed flat against the wall, so rainwater stayed trapped between them. There were gaps between the sheets, and the wood was of lower quality.

Advice. Stop using the balconies. Don’t put scaffolding on the existing balconies, because that would be irresponsible. Demolishing and rebuilding was probably cheaper than repairing.

Why it matters. Sometimes the honest advice is that repair no longer pays.

Case 8: a concrete balcony as a cold bridge, Hilversum

Situation. An owners’ association, block of flats from 1957, June 2025. Investigation into recurring damp patches.

Findings. The top of the concrete balcony was not watertight, with penetrating damp and concrete rot. On top of that, the concrete ran through to the inside. In winter the ceiling under the balcony got cold, with condensation and black mould.

Advice. Make all balconies watertight on top and then repair the underside. There is little to be done about the cold bridge itself: it is a design flaw. Insulating the ceilings is possible but expensive.

Why it matters. Not every damp patch under a balcony is a leak. If you don’t find out, you pay for the wrong solution.

Case 9: a washing machine drain that leaked for years, Hoofddorppleinbuurt

Situation. An owners’ association, building from 1934, May 2024.

Findings. The underside of the balcony was badly affected; concrete rot was suspected. The cause was a disconnected washing machine drain that had been leaking onto the balcony for years. Behind the railing there was wood rot in the plywood. The railing was not properly fixed in the wall, and the balcony had been attached to the neighbours’ balcony with a steel plate.

Advice. Connect the drain properly, repair the balcony, fix the railing with stainless steel screws and have a structural engineer assess the structure.

Why it matters. A small cause can do major damage unnoticed for years.

Case 10: one balcony first as a trial, Utrecht

Situation. An owners’ association with four concrete balconies, September 2026.

Findings. The balconies were not watertight in five places: the downpipe passage, an internal corner, the pointing, the lead flashings and the tiles on the edge. There was concrete rot with rusting reinforcement and damage to the steel beam under the balconies. All four were rated poor.

Advice. Remove loose parts, sandblast, de-rust and seal all leaking spots. Have one balcony done first as a trial, so it becomes clear what is under the surface.

Why it matters. A trial balcony stops an owners’ association from spending too much or too little in one go.

Case 11: a railing a child can climb over, Alkmaar

Situation. Pre-purchase inspection of an upstairs apartment from 1920, September 2022.

Findings. Small children could climb over the balcony railing. The lead flashing under the balcony door had been fitted incorrectly. Destructive investigation of the structure was not allowed during the inspection.

Advice. Close in the railing straight after the purchase, then it doesn’t have to be replaced. Have the load-bearing structure investigated after all once the purchase is done.

Why it matters. Not every defect is expensive. But with a safety risk you don’t wait.

Case 12: flue gases under the balcony and a roof terrace without calculations, Amsterdam

Situation. An owners’ association, four-storey building from 1937, September 2021.

Findings. The steel structure of the balconies was badly affected, partly because of a flue outlet under the balcony that blew moist gases against the steel. There were cracks at an anchor in the facade. On the flat roof stood a timber roof terrace that had never been structurally calculated.

Advice. Stop using the balconies, prop them immediately and have them fully renovated, estimated at € 40,000. Remove the roof terrace completely.

Why it matters. A boiler, a washing machine or a downpipe can damage a balcony just as much as the weather.

10. What you can do as a buyer or owners’ association

Check the minutes and the long-term maintenance plan (MJOP) of the owners’ association to see whether the balconies have ever been investigated or renovated, and when.
Ask whether there is a report from an earlier investigation, and whether destructive investigation was done.
Look at the underside of the balcony and the facade around it yourself: rust, spalled concrete, cracks.
Ask who built the balcony or roof terrace and whether there is a permit and a structural calculation.
Does the balcony have a railing small children can climb over or through? Take that into account in the negotiation or in your planning after the purchase.
If major costs are coming, work out what your share is. In old buildings it sometimes means tens of thousands of euros for the whole association.

A long-term maintenance plan helps you see major balcony costs coming in time. More in the VvE maintenance plan knowledge base. A leak under the balcony? See roof and facade leak investigation. Read also Basement Inspection, Crawl Space Inspection and the general Premiumkeur Amsterdam knowledge base.

Housing corporations often have balconies and walkways checked periodically. In the province of Limburg, more than 3,000 balconies and walkways were found unsafe after such checks in 2017 (NOS, 26 July 2017, in Dutch). For private owners and owners’ associations there is no fixed inspection requirement. In our reports we advise an owners’ association to have the balconies checked about every six years after repair.

Frequently asked questions

How do I know if my balcony is still safe?

Watch for rust stains, crumbled concrete, cracks in the brickwork around the balcony, a balcony that slopes or sags and a railing that moves. If you see one of those signs, have the balcony looked at. The load-bearing beams are often inside the facade and only half visible from outside.

What is concrete rot on a balcony?

Water gets into the concrete through small cracks. The steel inside starts to rust, expands and breaks the concrete. You see brown rust stains, spalled pieces and sometimes bare reinforcing steel.

How high does a balcony railing have to be?

For new buildings the Dutch Building Works (Living Environment) Decree requires at least 1 metre, and 1.2 metres with a height difference of more than 13 metres. In the bottom 0.7 metres, openings in a home may be no wider than 0.1 metres. Lower requirements apply to existing buildings; we use the new-build figures as our safety benchmark.

Who pays for balcony repairs in an owners' association?

That depends on the deed of division and the regulations. In many buildings the balcony is a common part, even if only you use it. Then the owners' association pays and the costs are shared in proportion.

Does a coating help against concrete rot?

A watertight coating can protect a sound concrete balcony well. Over rusting steel or loose concrete it doesn't help. Then the concrete and steel have to be repaired first.

What does balcony repair cost?

In our reports it ranged from about € 125 for a loose railing to € 28,900 to € 50,000 for the balconies of a whole facade with a rusting steel structure. Renewing a timber balcony cost about € 6,000.

What does a balcony inspection cost?

A balcony inspection at Premiumkeur costs from € 699 including VAT, also when there are several balconies.

Can Premiumkeur recommend a contractor?

No. Premiumkeur does not carry out repairs and does not recommend contractors. That keeps our advice independent.

Videos and sources

On our Premiumkeur YouTube channel you can watch our inspectors at work. About balconies: Balkon inspectie Amsterdam and Wat is betonrot en hoe ziet het eruit? (both in Dutch).

Sources: the figures and cases on this page come from 94 of Premiumkeur’s own reports (2018 up to and including 2026) in which a balcony, roof terrace or balcony railing was assessed. Reports by other companies were not counted. Addresses and names have been left out; the amounts are as they were in the reports. External sources: IPLO, rules for barriers in new buildings (Besluit bouwwerken leefomgeving); Omroep Brabant (2 September 2021); NOS (26 July 2017 and 18 November 2025); Rijksoverheid, doorstep selling.

All services and prices are on Diensten en tarieven (in Dutch).

Contact details Premiumkeur Amsterdam

Premiumkeur B.V., Heiligeweg 30, 1012 XR Amsterdam
Phone: +31 20 773 6842
Email: premiumkeur@gmail.com
KvK 81106130

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