Crawl space inspection Amsterdam FAQ

In short

• A crawl space inspection at Premiumkeur costs € 499 including VAT and a written report.
• Premiumkeur goes into the whole crawl space where it’s safe to do so. Many inspectors only look around the hatch.
• Most crawl space problems come down to moisture and ventilation.
• Don’t let anyone sell you insulation beads as a cure for damp.

Answers by Fred Tokkie, owner of Premiumkeur. He was a contractor from 1983 to 2009 and has inspected houses in Amsterdam since 2009. Updated on 6 November 2026.

Cost and method of a crawl space inspection

How much does a crawl space inspection cost?

At Premiumkeur it’s € 499 including VAT and a report. For that we go into the whole crawl space where it’s safe, rather than just looking around the hatch. You get a report with photos of what we find, such as damp, wood rot, fungi or a damaged concrete floor.

Why does a full crawl space inspection matter, for example with rotten floor joists?

Rotten joists are a common problem. In older houses the joist ends sit in the walls. If the house stands in a damp spot and the ventilation is poor, the joists start to rot.

That’s why a full crawl space inspection is so important when you buy. An inspector who only looks around the hatch will see very little of this and will often tell you to arrange further investigation. By then you’ve usually moved in, and the cost lands on you afterwards.

You can avoid that by having the crawl space properly inspected during the building survey. So stay away from companies that offer quick, superficial inspections.

How do you repair a leak in a crawl space you can’t get into?

The only way is to have a crawl space hatch made. If there’s a concrete floor above the crawl space, a hole has to be cut in it. If the crawl space is too shallow, the sand has to be vacuumed out so people can get in and do the repair.

Water, damp and smells in the crawl space

There’s water in my crawl space. What should I do?

First find out where it’s coming from: groundwater, a leaking sewer pipe or rainwater drain, or a water pipe. If it’s groundwater, there’s not much you can do yourself. In that case make sure the crawl space is ventilated as well as possible.

How do I find the cause of water or a musty smell in the crawl space?

The only way to be sure is a crawl space inspection. It can only be done once the water has been pumped out: standing water means a risk of electrocution.

My crawl space floods after heavy rain. What does that mean?

That almost certainly points to a problem with the sewer or the rainwater drainage. Have it looked at before the timber in the crawl space starts to rot.

Where does a musty smell or stench from the crawl space come from?

Roughly speaking there are three kinds of smell: sewer smell, an earthy smell, and a smell like mushrooms in a forest. That last one nearly always means a damp problem. A sewer smell means the drains aren’t sealed properly. An earthy smell isn’t necessarily a bad sign.

How do I fix a damp crawl space in a 1930s house?

Improve the ventilation, for example with a ventilation unit and a layer of shells or lava granules over the soil. Don’t let anyone talk you into EPS beads or insulation chips as a fix for damp: they do insulate the floor, but they don’t solve the damp problem, even though they’re often sold that way.

My house is new, but the crawl space is damp. How is that possible?

It’s common in houses where the groundwater is high. Our advice is to have a ventilation unit with a humidity sensor fitted, so the moisture that builds up in the crawl space is blown outside.

Mould and fungi in the crawl space

I can see mould in a damp crawl space. Is it dry rot?

Not every mould is dry rot (huiszwam). Dry rot is a fungus that attacks wood: you see white to grey cotton-wool-like strands on the timber, and sometimes a fruiting body that looks like a flat mushroom. It grows when wood stays damp for a long time, for instance because of a long-running damp problem in the crawl space. If in doubt, have an expert look at it, because dry rot can spread through timber quickly.

Is this a fungus or just mould in my crawl space?

Cellar fungus is named after damp cellars, but you also find it in damp crawl spaces. Dry rot is common in crawl spaces too, and in other warm, damp places in the house. Whether it’s a fungus or ordinary mould is something an expert can judge on site.

Joists and concrete floors

Should rotten joist ends or beams be repaired or replaced?

That depends on how far the rot has gone. Often they can be repaired, but if the beams are badly affected, replacement is needed.

Is my beam still strong enough if it has cracks in it?

Cracks along the length of the beam don’t weaken it, but if you’re unsure it’s always wise to get a building expert to look at the beams in person.

When should I have the floor structure or the main support beam inspected?

The support beam under the joists (onderslagbalk) is an important part of the floor structure. If it’s no longer sound, the floor sags in the middle. A thorough crawl space inspection is often the only way to tell whether that beam is still in good condition.

What is a kwaaitaal floor and how do I recognise one?

Kwaaitaal and manta floors are similar floors made of precast concrete elements with a half-round shape on the underside. They were widely used between 1960 and 1980. Concrete rot is common in this type of floor.

Can a kwaaitaal floor be inspected with X-rays?

No, you have a kwaaitaal floor inspected visually from the crawl space. That’s the best method. Kwaaitaal floors were mainly laid between 1960 and 1980. From the crawl space you can see cracks, crumbling concrete and rusting reinforcement. A kwaaitaal floor inspection at Premiumkeur costs € 499.

My concrete floor is sagging and the reinforcement is exposed. How serious is that?

The seriousness and the cost can only be judged by an expert carrying out a building inspection. Rusty, exposed reinforcement means the concrete is deteriorating, and a sagging floor can lose its strength. Don’t leave it too long. A kwaaitaal floor or concrete rot inspection at Premiumkeur costs € 499.

What does concrete rot look like and what does repair cost?

Cracking and crumbling concrete. You usually see rusted steel. The cost of repair depends on how bad the damage is.

There’s a bit of concrete rot in my floor. Is that serious?

Yes, it is, because concrete rot is nearly always caused by moisture. If you wait too long the damage gets worse, and it can seriously weaken the floor structure.

Videos

On our YouTube channel we show how Premiumkeur carries out a crawl space inspection. The videos are in Dutch, but the pictures speak for themselves.

Read more

• Crawl space inspection
• Damp inspection Amsterdam FAQ
• Building inspection Amsterdam FAQ
• Buying a house in Amsterdam

Question not answered?

Choose your own inspector, not one from the agent’s network

Because the Dutch system is new to you, it’s natural to follow your estate agent’s suggestions. Keep in mind that the agent is paid when the sale goes through. Choose an independent inspector yourself, even if the agent or mortgage adviser mentions a partner. Ask: will you go into the crawl space and onto the roof where it’s safe, and can you confirm your independence in writing? Premiumkeur doesn’t work with estate agents or mortgage advisers, doesn’t pay or receive referral fees and doesn’t recommend repair companies.

Call or WhatsApp us. We speak English and can provide an English report for € 100 extra.

See all our services and prices (in Dutch).

Use of this information

This page gives general information based on our own inspections. It doesn’t replace an inspection of the house you want to buy. Prices include VAT and were correct in November 2026.