This article outlines some of the more common building defects and issues relating to dampness and condensation. It is relevant to residential, commercial and industrial buildings.
What is ‘Damp’?
From a human perspective, whether a wall, ceiling, or floor is ‘damp’ is partly subjective. In many cases, dampness is often only noticed after it has caused visible internal damage to finishes; such as staining, flaking paint, and mould growth.
Most materials used in construction are porous; the level of porosity is often related to the density of the material. A completely dry porous material would only be found in a laboratory, after oven drying; however, materials are usually able to function satisfactorily if moisture levels remain within certain limits. However, elevated moisture levels can lead to problems.
If not actioned promptly, elevated moisture levels can have serious consequences for the building finishes, and even the structure. Finishes can be damaged or destroyed, timber may rot and decay, and metal may corrode and fail.
A damp-proof course within a wall, or a damp-proof membrane within a floor might fail, and become a problem; causing deterioration of carpets and floor coverings, rot to skirting boards and door frames. However, it is not that common to have a failed damp-proof course, and many builders and professionals have effectively wasted client’s money in the past, putting in a new damp-proof course, when it was not needed.
Dampness affecting finishes at low level, requiring investigation
Building services pipework is susceptible to leakage, and this is one of the more common causes of internal dampness. Sometimes a leaking pipe goes unnoticed for a lengthy period, and what was a minor problem, suddenly becomes an expensive job to rectify. Below is a case in point, where an internal pipe was leaking for over four years, and the owner was on the point of carrying out expensive damp-proofing works, as recommended by a specialist contractor.
External and internal damage caused by a slow leak on a pipe under a sink
Condensation is a form of dampness, but is largely misunderstood by many. The main factors that can lead to condensation on internal building surfaces are high humidity of indoor air, low surface temperature, and inadequate ventilation. Air moisture condensation generally takes place during the colder months, (from October to April), and is known as the ‘condensation season’. Condensation can occur on any cold surface, including decorations, wall coverings, windows, glass, ceilings, and cold pipework. Even a toilet cistern can act as a sort of condensation ‘magnet’ to allowing moisture to condense, and it drips onto the floor.
Condensation on a WC cistern and mould growth in the corner
It is possible to have both penetrating and rising dampness in a property, together with condensation. This is because condensation occurs when the surfaces of materials are relatively cold, and the air cannot hold any more moisture. Increase your heating substantially, and it may well reduce, for a time. Building surveyors are trained to detect and differentiate between condensation and other types of dampness.
But be under no illusion; dampness from condensation can be as destructive to building materials such as timber or plasterwork as other dampness sources. It is after all, just water or moisture.
Escape of Water and ‘Flooding’
Some people talk of having a ‘flood’ to their property, when they actually mean it has been an escape of water, e.g. from a cold-water storage tank, a hot-water cylinder, or burst pipes in winter. The remedial work needs to be planned with great care to avoid fungal growth in floors, walls, ceilings, and structural damage.
A floor damaged after substantial escape of water to a property
Flooding, on the other hand, may be catastrophic; caused by overflowing culverts and rivers, etc. Again, the building surveyor will know how to approach the reinstatement of the property, and there are recognized stages that have to be followed, to ensure careful drying of the property.
‘Cupping’ of new floorboards following inadequate drying after an escape of water
Mould and Dampness
Mould and Dampness tend to go together like bacon and eggs! Fungal decay and mould often result, following water-ingress or dampness through the structure. This can be noticed on wallcoverings, paintwork and finishes. Sometimes the fungal mould is easy to remove and eliminate, other times, are much more challenging.
Mould Growth on a plastered wall Mould growth concealed by a bed
Structural Damage and Timber Decay
Steelwork within buildings, such as that used to reinforce concrete members or form structural elements, can corrode if not adequately protected from water. The expansion of metal when it is corroded creates a powerful force, sometimes referred to as ‘Metal Jacking’. Metal corrosion can cause structural as well as cosmetic damage.
Underside of fire escape landing & Reinforced concrete canopy
Timber can decay and rot, resulting in wet rot, or the more serious ‘dry rot’ or Serpula Lacrymans.
The question for the client, and his or her building surveyor, will be to initially assess the scale of the problem, and the degree of damage caused by the damp and decay.
Are the ends of the timber joists or rafters decaying and losing their structural strength? Has the leaking pipework over the years been the source and cause of the dry rot, now spreading to the neighbouring property? Will I, as client or occupant, have to move out of the property temporarily, whilst remedial works are done? How long for? Is there a possibility of an insurance claim being made to recover some or all the costs?
Timber decay in tie beams to a roof Internal timber decay to a window
Most insurers of property expect the policyholder to keep their property in satisfactory repair. Yet, they still tend to pay out when there has been a burst pipe in the middle of a cold winter, even though the pipe might not have been properly insulated. They may cover some of the contents damage too. But one needs to be cautious here. There are many situations whereby claimants are disappointed, and find insurers not paying out in situations where they consider the property was poorly maintained.
Drying out following escape of water
An experienced chartered building surveyor can assist here. They can collect the evidence with photographs, opening-up the structure, and produce a schedule or building defects report. They can arrange testing of materials, identify the moisture content, and determine the remedial action and programme. They can liaise with specialist timber treatment firms and damp-proofing contractors, to ensure that money is well spent, and not wasted.
A moisture meter needs to be used with care to avoid incorrect diagnosis
A Building defects report on dampness in a property can be issued to the client with a description of the problem, options for solutions, and an indication of estimated costs and programme, where required.
Arun Associates can manage everything from production of a technical defects report, to project management and programming of the remedial works. Where insurance claims are affected, they have the experience to assist with those, and in discussions on claims with loss adjusters.
Please contact us on the main number or email us, at Arun Associates for a discussion, on a no-obligation basis.