Leak detection Haarlem

A ring on the ceiling after a stormy night, a damp wall in the bedroom, or a patch under the roof window that never dries: in Haarlem and the rest of Kennemerland the cause often comes from outside, but far from always from the roof. On this page we explain how we trace a leak, what is different in this region compared with the inland areas, and what you can do yourself before you call anyone in.

Nederlandse versie: Lekkage opsporen Haarlem

Premiumkeur Haarlem is based at Tempeliersstraat 63 in Haarlem and works throughout Kennemerland: Haarlem, Heemstede, Bloemendaal, Zandvoort, Velsen, Beverwijk, Heemskerk and Castricum. We are an independent building consultancy. We do not carry out repairs and we do not recommend roofers or contractors.

In brief

• Tracing leaks in your home costs € 499 to € 599 with us, tracing roof leaks starts at € 599 and leaks at the facade start at € 499. You have the report within two working days.
• We search inside and outside: roof, gutters, lead, facade, window frames, balconies and, where needed, the bathroom and pipework.
• The inspection is visual and non-destructive. We only open anything up in consultation with you.
• With a leak, several causes often play a part at the same time. The report states which one is the most likely and in which order it is best to deal with them.

1. Leaks in Haarlem and on the coast: wind and driving rain

Kennemerland lies close to the sea. The prevailing wind comes from the west and southwest, and in a heavy shower rain is pushed not only onto the roof but also sideways against the facade. You can see that in where the water gets in.

• The weather side. A damp patch on a west or southwest wall that mainly gets wet after rain with strong wind points more to the facade, a window frame connection or a sill flashing than to the roof.
• Connections high up in the facade. Lead flashing at chimneys and dormers, the junction between roof and facade, and zinc roof edges take the most punishment in a storm. A flashing that is just too short or has blown loose lets water through in a gale that would simply run off in ordinary rain.
• Closer to the sea. In Zandvoort, IJmuiden and other coastal towns, salt and wind work harder on metal, pointing and sealant joints. Fixings rust faster and sealant weathers sooner.
• Old city centre. The centre of Haarlem has many old buildings with solid walls, concealed gutters behind the facade and dormers that were added over the years. There are many connections there, and so many places where water can find a way in.

2. From damp patch to cause: four questions we always ask

Before we measure anything, we want to know the pattern. Feel free to go through these questions beforehand; it saves time on the day.

1. When does it get wet? With every shower, only in strong wind, only after showering or doing laundry, or all year round?
2. Since when? A leak that started after work on the roof, the facade or the bathroom often points to that work.
3. What has already been done? Sealant, new tiles, a repair by a roofer? An emergency repair that did not help also tells us something.
4. Who lives above, next to or below you? In an apartment or terraced house the source can be at the neighbours’: a shared gutter, a balcony that drains onto yours, a bathroom above.

3. Types of leak we trace

Roof leak

Rainwater that gets in through the roof covering, a seam, a penetration, a roof window or the connection with a facade. On flat roofs it is often in the upstands, the outlets and old repairs; on tiled roofs it is in lead, gutters, valley gutters and dormers.

Facade leak

Water that is drawn in through weathered pointing, cracks, porous brickwork or poorly fitted window frames. With solid walls without a cavity, the water shows up directly on the inside.

Leak inside the home

A bathroom that is not watertight, a leaking drain or pipe, or a central heating system. A leak like this often causes damage for the neighbours below, even if you notice nothing yourself.

Damp that is not a leak

Condensation and rising damp look like a leak, but need a very different approach. Part of our work is precisely telling the two apart, so that you do not pay for a roof repair when the problem is in the ventilation.

4. How the inspection works

1. Intake. By phone or by email, with photos if you have them.
2. Measuring inside. With a pin-type moisture meter in the material itself, at several spots. That shows us whether the patch is still actively wet or an old ring.
3. Outside and on the roof. The inspector goes onto the roof if that can be done safely and responsibly, and looks at the roof covering, gutters, lead and zinc, penetrations, roof windows, chimneys and the connections with the neighbours.
4. Facade, window frames and balconies, from the street, the balcony or the roof.
5. Extra tools where they add something: an endoscope to look behind a ceiling through an existing opening, a thermal imaging camera, a humidity meter or a simple water test.
6. Explanation on site and a report within two working days, with photos, the condition of each element, the most likely cause and the order in which to tackle things.

What we cannot see without opening something up, such as what lies under roof covering, gravel or decking, we write down. A leak that only occurs in a storm from one direction cannot always be demonstrated on a calm day. That is also stated honestly in the report.

5. What you can do yourself

• Keep a note of when it leaks, with the date, the weather and the wind direction. After a few showers you can often see a pattern.
• Mark the edge of the patch with pencil, so you can see whether it grows.
• When it rains, look from the street or balcony to see whether water runs over the edge of the gutter.
• Ask the neighbours and the owners’ association (VvE) whether they notice anything too.
• Do not go onto the roof yourself if it cannot be done safely, and do not start applying sealant before the cause is known. An emergency repair can remove evidence.
• Do not paint too early. After the repair, have the wall measured to see whether it is dry.

6. Free leak detection: how it works

In Haarlem and the surrounding area you will also come across offers for free leak or roof leak detection, often from roofers and plumbing companies. Free usually means you do not pay separately for the search. With a company that also carries out the repair, that time is earned back through the work that follows. Whoever establishes the cause then also earns from the solution.

That is a common model and it says nothing about the skill of an individual roofer or plumber. It does make the advice harder to check. So when you get a quote, always ask which cause was established and how, and have the quote split into what is needed to stop the leak and what is maintenance or improvement. If the leak comes back after a repair, or the amount is large, an independent inspection beforehand is often worth the effort. With one report you can have several tradespeople quote for the same work.

7. Case studies from Haarlem and Kennemerland

These cases come from our own reports. The first two are leak and damp investigations; the other five are purchase inspections in which leaks, damp and the roof played an important part. For those we only mention the relevant findings. Addresses and names have been left out. Amounts are only given where the report mentions them.

Case 1: Damp crawl space and mould, Heemstede

Situation. Terraced house with three storeys, year of construction unknown, no owners’ association (VvE). May 2024. The resident asked for an independent damp inspection and wanted to renovate the ground floor.

Findings. The crawl space under the kitchen was very damp: discoloured sand-lime brick, salt efflorescence and wet tiles. Under the living room it was also damp, the floor sprang under foot and the joists were carrying too little. There was no ventilation in the rear facade. At the front facade there was black mould on a cold wall due to condensation and rising damp. A radiator in the hall leaked at the connections.

Advice and costs. We advised mechanical extraction with a humidity sensor through a 130 mm hole in the front facade (125 mm PVC pipe), replacing the floor joists with concrete beams and a ribbed concrete floor, an insulated lining wall and mechanical ventilation. No amounts in the report.

What this shows. Mould and a springy floor had the same cause: a crawl space without ventilation. With damp complaints, also look under the floor.

Case 2: Leak from a restaurant to the shops below, Beverwijk

Situation. A restaurant on the first floor of a building with an owners’ association, with shops on the ground floor. Year of construction unknown. June 2021. The trigger was leaks at the neighbours below.

Findings. Meltwater from a refrigerated unit ran away through a broken drain, hidden in a cupboard, and that went unnoticed until the shopkeepers complained. In the kitchen the silicone sealant of the liquid-tight floor had come loose in several places, partly from daily scrubbing. The water ran down between the tiling and the wall. The sealant around the floor drain had also come loose. The concrete floor elements do not join up watertight.

Advice and costs. Silicone sealant should be replaced every six years; we advised doing this every year. No amounts in the report.

What this shows. On the first floor a leak stays hidden for a long time. With normal use, small sealant damage is then enough to cause damage downstairs.

Case 3: Facade and window frames at purchase, Haarlem-Centrum

Situation. Purchase inspection of a building from 1881 with three storeys, object type commercial building but used as a home, no VvE. July 2025.

Findings. In places the pointing was missing. Hairline cracks in the paintwork let moisture get behind the paint. Many crawl space vents were blocked. Window sill stones were loose or the joints had silted up, with a risk of water seeping in. At one window frame there was a wide open gap towards the facade. The bitumen on the extension looked recently replaced. The cost overview also mentions the gutters.

Advice and costs. Call in a pointing and painting company, clean the vents, repair the sills and make the frame joint watertight. 2025 price level, excluding scaffolding: pointing € 900, exterior painting € 1,600, vents € 250, sill stones € 200, frame joint € 125, extension bitumen € 150, gutters € 250 now and € 6,500 in the longer term.

What this shows. Much of the leak risk lies in small facade defects, which can also be repaired separately at purchase.

Case 4: Water damage in the roof boarding at purchase, Haarlem-Oost/Schalkwijk

Situation. Purchase inspection of an unoccupied corner house from 1981 with three storeys, no VvE, without foundation investigation. July 2025.

Findings. There was no vapour-permeable membrane under the concrete roof tiles. The roof boarding showed traces of water damage in several places. The moisture readings were slightly above the limit values: an active leak, or residual moisture that has not yet dried out. The tiles are nearing the end of their theoretical life of 30 to 50 years; we expected another 10 to 15 years. The fascia boards at the rear were rotten from overdue painting.

Advice and costs. Have a leak detection company look before you sign the purchase contract, check the roof periodically and replace the rear fascia boards. 2025 price level: roof boarding € 450, leak and damp patches € 500, fascia boards € 1,200.

What this shows. Slightly raised readings do not tell you whether a leak is active. It is better to know that before the purchase.

Case 5: Leak patch and roof details at purchase, Heemstede

Situation. Purchase inspection of an occupied terraced house from 1923 with three storeys, no VvE, without foundation investigation. October 2024.

Findings. In the attic there was a leak patch near the central heating boiler. The reading stayed below the limit values, so it was not active. Some roof tiles did not fit properly where pipes pass behind the tiles through the roof boarding into the house. The rainwater pipe ended on the flat roof and was hanging by a piece of wire from the neighbours’ balustrade. In the second bathroom the joint next to the wall-hung toilet was open. Pipework in both bathrooms was concealed and could not be checked for leaks.

Advice and costs. Keep an eye on the patch, have a roofer repair the tiles, connect the downpipe to a rain barrel or the sewer and seal the joint. 2024 price level: roof tiles € 300, rainwater pipe € 350, bathroom joint € 150.

What this shows. A dry reading on a single day does not rule out an old leak. Concealed pipes remain a residual risk with a visual inspection.

Case 6: Loose roof covering and wall copings at purchase, Zandvoort

Situation. Purchase inspection of an occupied detached house from 1905 with two storeys, no VvE, with foundation risk phase 0. April 2026.

Findings. The high roof had recent bitumen, apparently laid over the old covering. Against the facade upstands the adhesion was insufficient and the covering had come loose in several places. There were already signs of leaks inside. Several corners of the wall copings had broken off, a large part at the rear, leaving an open connection to the structure. The chimney flue had cracks in the cement mortar. At the roof light the report pointed to the duty to investigate earlier leaks.

Advice and costs. A roofer in the short term, replace the wall copings completely with enough overlap over the roof covering, repair the chimney and renew the lead flashing. 2026 price level: high roof € 1,750, wall copings € 5,500, chimney € 900.

What this shows. Even a recent roof can leak if the connections have not been made properly.

Case 7: Flat roofs and chimneys at purchase, Haarlem-Noord

Situation. Purchase inspection of an occupied terraced house from 1920 with three storeys, no VvE, without foundation investigation. April 2025.

Findings. The bitumen covering of the second flat roof was poor: seams and overlaps were coming loose and the surface showed crazing. The lower flat roof could only be assessed to a limited extent because of decking. There was weed growth against the roof edges and the lead did not reach over the fascia board. On the chimney the top layer of the concrete slab was coming loose, pointing above the lead flashing was loose and the flues had no rain caps. At the valley gutter several tiles were not fixed properly.

Advice and costs. Replace the second roof in the short term, remove the weed growth, repair the lead flashing, fit caps. 2025 price level: second roof € 1,650, lower roof € 300, chimneys € 1,400, roof tiles € 900.

What this shows. With flat roofs the risks lie in the seams, edges and drainage, not only in the covering itself.

Cases 8 to 10 are damp inspections from 2024 up to and including 2026.

Case 8: Damp patches above the front door caused by rainwater, Haarlem

Situation. Upstairs apartment from 1910, owners’ association (VvE): yes, occupied. In February 2026 the VvE had a moisture inspection carried out after complaints in a recently occupied apartment.

Findings. Inside, there were damp patches at the top left of the front door. A measurement above the door showed an elevated moisture level on the inside (no value in the report). The decorative moulding above the door had defects in the paint and damage to the material. We therefore see a direct link: rainwater is penetrating the construction. On the rain side we also saw an opening in the moulding under the gutter with early wood decay, and many cracks in the stucco of the side facade.

Advice and costs. Have the moulding repaired by a painter and seal the opening under the gutter urgently. Seal the cracks now as an emergency repair and have them repaired by a plasterer during major maintenance. Then assess whether impregnating is needed. No amounts in the report.

What this shows. The cause of a patch on the inside can lie in a damaged facade element on the outside.

Case 9: Mould and moisture in a bedroom, Haarlem-Centrum

Situation. Rented ground-floor apartment from 1906, VvE: yes, occupied. In January 2026 the landlord asked for an investigation into moisture and mould in the bedroom.

Findings. At the head of the bed there were damp and mould patches at skirting height, at about 60 and 80 cm above the floor and at the top right. The measurement (a snapshot) showed a very high moisture level at the skirting and dry at the ceiling. The brick wall is not insulated and cools down, which gives condensation, especially without a ventilation grille in the transom window. Outside, the paint layers of the rear facade and garden wall were cracked and peeling, with a lot of algae, and the courtyard has one drainage point whose function is unclear. Rain therefore also penetrates (penetrating damp).

Advice and costs. Have the mould treated professionally, fit a ventilation grille in the transom window and air the room daily. Clean and paint the facades, inspect the gravel soakaway. Possibly inject the wall from the inside. No amounts in the report.

What this shows. The mould has more than one cause: rain, a cold wall and too little ventilation reinforce each other.

Case 10: Penetrating damp in a bedroom, Haarlem-Centrum

Situation. Upstairs apartment from 1930, VvE: yes, occupied. In December 2024 we carried out a moisture inspection after persistent moisture complaints.

Findings. In the bedroom we saw clear signs of penetrating damp (condition poor). Measurements showed no elevated moisture level at that moment. On the other side is an external wall with the neighbours’ gutter: the pointing is very poor in places and the gutter is aged. Emergency repairs were made earlier: rainwater downpipe rerouted, compression strip at the gutter and lead or synthetic lead. These presumably had an effect.

Advice and costs. Have the paintwork inside repaired. For later: plaster the facade with water-repellent mortar and a lead flashing, or impregnate it several times (simpler, presumably less durable). No amounts in the report.

What this shows. A dry measurement here means that the emergency repairs seem to work, not that the risk is gone.

8. Frequently asked questions about leak detection in Haarlem

What does leak detection in Haarlem cost?

Tracing leaks in your home costs € 499 to € 599 with Premiumkeur, tracing roof leaks starts at € 599 and leaks at the facade start at € 499, including VAT. You have the report within two working days.

Why does it only leak in a storm?

In strong wind, rain is pushed against and under connections: lead flashings, window frames, sill flashings and the junction between roof and facade. In ordinary rain the water simply runs past them. A patch that only gets wet in a storm from one direction therefore often points to the facade or a connection, not to the roof covering itself.

Do you also investigate leaks in the bathroom or at pipes?

Yes. We look inside and outside in every inspection. A patch on the ceiling can also come from a bathroom or drain above it, especially in an apartment.

Do you break anything open?

In principle, no. The inspection is visual and non-destructive. If opening something up is needed to be sure of the cause, we discuss it first and the report states which follow-up step is needed.

Can you find a leak when it is dry?

Often yes, because we assess the condition of the roof, facade and connections and measure moisture in the material. A leak that only occurs with a particular combination of rain and wind is harder to demonstrate in calm weather. That is then stated in the report.

Do you recommend a roofer or plumber?

No. Premiumkeur does not recommend roofers, plumbers, contractors or other repair companies, so that we have no interest in the repair.

Who pays for a leak in an apartment?

That depends on where the cause is and what the deed of division says. In many owners’ associations the roof, facade and gutters are shared. We record the cause, but we do not give legal advice.

Why pay for leak detection when it can be free?

With free leak detection by a company that also does the repair, the time is usually earned back through the repair work. That need not be a problem, but whoever establishes the cause then also earns from the solution. We do not carry out repairs; you only pay for establishing the cause.

How long before I can paint?

That depends on the wall and how long it has been leaking. Solid walls in older buildings can take months to dry. Have the wall measured first to see whether it is dry.

9. Videos of our leak investigations and roof inspections

On the Premiumkeur YouTube channel you can watch our inspectors at work: on flat and pitched roofs, at gutters and chimneys, in crawl spaces and with the moisture meter and thermal imaging camera.

10. Further reading

• Roof inspection Haarlem: what we look at for each type of roof and how to have a roofer’s quote checked.
• Building inspection Haarlem knowledge base: the building inspection, foundations and buying in Kennemerland.
• Leak detection Amsterdam knowledge base from Premiumkeur Lekdetectie, with figures from 278 reports.

Sources: the cases on this page come from Premiumkeur’s own reports. Addresses and names have been left out. Reference date: October 2026.

Contact details Premiumkeur Haarlem

Premiumkeur Haarlem, Tempeliersstraat 63, 2012 EC Haarlem
Phone: +31 23 234 0040
Email: premiumkeur@gmail.com
Premiumkeur B.V., Heiligeweg 30, 1012 XR Amsterdam, KvK 81106130

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