Buying a house with damp problems? A checklist for prospective buyers

Not every moisture problem is immediately visible behind a fresh coat of paint. Whether you have your eye on a charming renovation house in the city or a more recent new construction in the countryside, a sharp eye is always crucial.While touring your dream home, pay attention to the following things:

• The smell: Does it smell musty or cellar-like? Then this is often the first sign of a lack of ventilation or penetrating moisture.
• The walls and skirting boards: Are the wooden skirting boards bulging? Do you see salt efflorescence in the form of white, powdery rashes or wallpaper coming loose at the bottom of the walls? If so, this could also indicate a moisture problem in your home.
• The secret spots: Look behind cabinets that are against exterior walls and be sure to check ceiling corners too. These places are ideal for moisture development.
• Condensation on windows: Do you see many drops on the glass or black mould dots on the kit edge in the bathroom? If so, this could indicate a structural ventilation problem possibly resulting in moisture.
• The basement and the ‘bilge seam’: Take a light source to the basement. Check that the corner where the floor meets the wall, the bilge seam, is dry. Lime deposits or damp spots on the basement floor are signs that a costly basement waterproofing or -drainage may be needed.
• The outside (the facade): A good inspection actually starts outside. Do you see cracks in the facade, moss growth in specific areas or broken joints? These are the gates through which penetrating moisture now invades your home.

Saving tip: Notice any of these things? Then be sure to take pictures of them if you plan to buy your dream home anyway. These are your key pieces of evidence to knock hundreds of euros off the asking price during the price negotiation. After all, a house with damp is worth less, while with the right expertise is often solved faster than you think.

To draw up a budget for your dream home, you do need to know which moisture enemy you are dealing with.

• Rising damp: Groundwater soaking into walls due to the lack of a water barrier. You recognise it by moisture spots, loose plaster or salts starting at the bottom of the wall, up to about 1.20 metres high.
• Penetrating moisture: Rainwater seeping in through a porous outer wall, the façade. You recognise it by damp spots that appear at random heights, often after a heavy rain on the rain-side of the house.
• Damp walls: This moisture problem is often related to leaks or cold bridges. You recognise it by localised, wet spots that are cold to the touch.
• Damp basement: The basement is the lowest point of a house and therefore the most vulnerable. You can recognise it by puddles of water, a clammy floor or white salt rash on the walls. Pay particular attention to the bilge seam, where the floor and wall meet.
• Condensation moisture: Moisture created by everyday activities such as cooking and showering. You recognise it by fogged-up windows on the inside and water droplets on non-absorbent surfaces.
• Mould on the walls: The result of a long-term moisture problem or poor ventilation. You can recognise it by black, green or grey dots in the corners, behind cupboards or around window profiles.
• Moisture in new-build home: A new building can also have moisture. We are talking about residual building moisture. You recognise it by the windows that are constantly smashed by the thousands of litres of water in the construction that have yet to dry out further.

Moisture control is tailor-made. To give you an idea of the budget to provide during your negotiations, we have our specialised moisture solutions including guide prices listed.

Injecting walls against rising damp

When no water barrier is present, groundwater migrates up the walls. The most effective solution is to professionally injecting the walls with a water-repellent gel.

• Target price: From €100 per running metre.

Basement sealing or basement waterproofing

Is the basement of the property you have your eye on damp? At basement waterproofing or caulking, we make the walls and floor completely waterproof with several layers of cementation. This turns the basement back into a usable storage or living space.

• Target price: From €50 per sq m.

Basement drainage

When the groundwater pressure under the house is too high for an ordinary basement pit, basement drainage the only definitive solution. This involves the controlled discharge of water via a pumping system.

• Target price: For a total basement project, expect a starting price from around €2,000.

Concrete injections for leaks

In modern houses or basements made of concrete, hairline cracks or bilge seam problems can cause acute water infiltration. Concrete injection seal these leaks under high pressure.

• Target price: This price strongly depends on the severity of the leak and is customised during our free expertise.

Facade impregnation or hydrofuge

Does the property suffer from penetrating moisture? By the facade impregnation, we apply an invisible, protective layer that repels rainwater while the wall continues to breathe.

• Target price: This can be done from as little as €8 per m².

Ventilation system against condensation and mould

Moisture in the house does not always come from outside. Condensation and mould on the walls often indicate a lack of air ventilation. A professional ventilation system removes polluted, moist air and brings in healthy air.

• Target price: Ventilation solutions start from €1,000.

Plastering and finishing

After moisture control themselves, the walls often need to be repaired. AquaConsult also provides the plastering so your walls will be completely even and paint-ready again after treatment.

• Target price: The price of this depends on the surface area and the condition of the substrate.

How much budget should you provide in total now?

While the exact cost will depend on the severity of the damage and the total area, it is essential to plan a realistic overall budget before purchase to meet moisture control to be able to do so. For an average family home where the ground-floor walls need to be treated against rising damp, combined with a professional finishing of the plastering, you should consider a total budget between €3,500 and €7,000.

If there is also a damp cellar which needs to be fully waterproofed, the total renovation budget rises to between €8,000 and €15,000. By mapping out this total amount, including margin for contingencies, in advance, you will be in a stronger position during negotiations and avoid putting pressure on your renovation budget after purchase.