Damp in old buildings: Diagnosis and permanent technical solutions

26 Jun Damp in old buildings: Diagnosis and permanent technical solutions

Old buildings have a character of their own, but they also have a natural vulnerability to damp problems that are often treated incorrectly. It is common to try to cover mould stains or efflorescence with coats of paint, only to see the problem return a few weeks later in these buildings. Discover how you can solve it.

Old buildings require a different diagnostic approach

Addressing damp problems in old buildings requires a deep understanding of how these properties were constructed, as they often operate under physical dynamics that are very different from those of modern buildings. In traditional constructions, walls generally have greater thermal inertia and porosity, making them susceptible to three clear pathologies: rising damp, water infiltration, and condensation.

While rising damp is caused by water ascending from the ground through the pores of the building materials, water infiltration is usually the result of direct water ingress through cracks, deteriorated roofs, or poorly waterproofed planters. Condensation, on the other hand, which is common in refurbished properties with excessively airtight enclosures, occurs when indoor water vapour comes into contact with cold surfaces where it turns into liquid, encouraging the growth of mould.

Attempting to solve these problems by applying standard solutions without prior analysis is often the most costly mistake. In an old building, sealing a wall with waterproofing products can be counterproductive, as it prevents the wall from ‘breathing’, trapping moisture inside the structure and accelerating its deterioration. For this reason, it is vital to identify the exact mechanism before any intervention, avoiding superficial solutions that do not address the real cause of the pathology and that will inevitably fail in the short or medium term.

How to verify the real source of damp before carrying out repairs?

A professional technical diagnosis is the only reliable way to avoid unnecessary interventions. A specialist should carry out a protocol based on objective measurements that distinguish aesthetic symptoms from the actual condition of the building, thus avoiding the application of temporary fixes. The fundamental steps include:

• Use of a deep moisture meter: Allows the degree of material saturation to be measured at different points in the wall, distinguishing whether the source is superficial or deep.
• Analysis of hygroscopic salts: This is essential to confirm a rising damp process, as the salts deposited on the surface are a fingerprint of the constant evaporation of rising water.
• Thermal imaging camera assessment: Makes it possible to detect thermal bridges and hidden leaks that are invisible to the naked eye, particularly useful for locating areas where condensation is most concentrated.
• Water-tightness tests: These are carried out to rule out external water infiltration from roofs or downpipes affecting interior walls indirectly.
• Visual inspection of the surroundings: Assessing the foundations, the condition of the surrounding ground, and the property’s ventilation to understand the behaviour of the damp.

Choosing breathable materials for the restoration of old buildings

Once the cause has been identified, the choice of repair materials is crucial to the longevity of the work. In historic or traditional properties, chemical and physical compatibility is essential: we must prioritise the use of lime mortars and highly porous finishes that allow water vapour to migrate freely.

The use of rigid cement mortars or conventional plastic paints often blocks the wall’s breathability, creating internal vapour pressure that eventually cracks the finish and encourages the development of interstitial moisture. Choosing solutions that respect the building’s original breathing capacity is the best strategy to ensure the property remains healthy and dry in the long term.

Strategies to improve ventilation in enclosed spaces

When condensation is the main problem, managing indoor air becomes the absolute priority, especially in homes on the Costa del Sol where ambient humidity is high. To control this phenomenon from a technical perspective, we recommend implementing measures focused on continuous air renewal.

• Mechanical Ventilation with Heat Recovery (MVHR) systems: Installing single-flow or double-flow units ensures constant air renewal without compromising thermal efficiency, removing excess moisture before it condenses on walls.
• Thermal bridge control: Properly insulating areas where wall temperatures drop significantly, such as corners or window frames, to prevent them from becoming dew point locations.
• Optimising window systems: Ensuring that windows provide a controlled level of air infiltration or include self-regulating ventilation devices to prevent water vapour from becoming trapped in critical areas such as bathrooms or kitchens.

Professional diagnosis to solve damp problems at their source on the Costa del Sol

Treating damp problems in old buildings requires expert knowledge and respect for the original materials. There is no miracle solution or paint that will eliminate the problem if the root cause remains active. For this reason, a thorough diagnosis is the most worthwhile investment to protect both the structural integrity of your property and the health of those who live in it.

The complexity of pathologies in older homes requires specialised technical knowledge that goes far beyond the application of standard products. At Humilogic, we understand that every property in Marbella and the Costa del Sol presents unique challenges, shaped both by the local architecture and by the specific climatic conditions of our region.

Our method is based on a rigorous professional damp diagnosis: before proposing any intervention, we analyse the root cause to ensure that the solution is permanent rather than a temporary cosmetic repair. If you are looking for an expert technical assessment for your property or need advice on renovation projects, we invite you to request your professional diagnosis here, where we will evaluate your damp issue anywhere in the province of Málaga with the technical rigour your property deserves, helping you protect both the health of its occupants and the value of your investment.