Dampness is caused by excessive moisture in buildings, and is a common problem in housing, affecting 1.3 million homes in England. While damp is often highly visible, from moisture on walls to bulging plaster and mould, it can also cause less visible issues such as reduced thermal insulation and deterioration of building fabric.
Most concerningly, dampness in building construction has been linked to health hazards to occupants. Together, damp and cold homes are estimated to cost the NHS £1.4 billion annually, even leading to loss of life and the introduction of Awaab’s Law.
In this guide, we’ll go deeper into what dampness is in building construction and what landlords need to know in order to deal with it effectively.
Causes of Dampness in Building Construction
The Building Regulations Approved Document C, ‘Site Preparation and Resistance to Contaminants and Moisture’ requires buildings to be constructed with resistance to the harmful effects of moisture. The three most common causes of dampness in buildings are:
1. Normal Building Usage
The everyday activities of occupants, such as bathing and drying clothes, result in condensation. This is particularly apparent in buildings without adequate ventilation and with poorly insulated walls.
Condensation can result in water damage, particularly where moisture builds up in homes. For example, mould may be visible in horizontal and vertical corners of a building interior, such as around windows or shelving, where ‘dead air’ pockets can occur.
2. Rising Ground Moisture
Rising damp can take place when a building has a missing or ineffective damp proof course or membrane, or where these defences have been bridged by external ground works. It’s worth noting here that traditional buildings may not have a damp proof course if built before 1875, 1878 and 1897 in England and Wales, Ireland, and Scotland, respectively.
If you find a ‘tide mark’ in the lower section of a wall, this is a common indicator of rising damp and is caused by soluble salts from groundwater.
3. Component Failure
Penetrating damp is caused by rainwater entering a building. This usually happens where a component of the building has failed, such as:
- A missing roof tile
- Damaged render of cladding
- Inappropriate construction for the building’s exposure
- Missing or defective trays in cavity walls
- Porous masonry
- Defective seals around doors and windows
- Defective pointing
A Common Mistake in Dealing With Damp
When it comes to dealing with damp in construction, the most common mistake is misdiagnosis. Failing to understand the underlying cause of dampness can lead to costly, ineffective and damaging treatments, particularly in the case of traditional buildings.
Dealing with damp, mould and condensation in existing homes and buildings can be particularly complex. However, the risk is that ‘quick fix’ measures such as injecting chemicals or removing historic plaster may not only fail to treat dampness in a building, but also lead to further problems and disruption for occupants.
This is why qualifications to certify knowledge and expertise in dealing with damp, mould and condensation are becoming increasingly important. Find out more about our Level 3 Award in Damp, Mould and Condensation in Buildings here, led by Professor John Edwards.
BS 5250:2021 and Dealing with Moisture Issues in Buildings
To look at best practice in dealing with dampness in building construction, let’s start with BS 5250:2021. This is the British standard and primary method of assessing moisture compliance according to UK building regulations and applies to all types of buildings.
Informed by research and practice, BS 5250:2021 sets out a holistic approach for managing moisture in buildings, reflecting progressively higher standards for the airtightness of new buildings and improving thermal insulation.
The 2021 version has a particular focus on condensation risk in new buildings, including practical recommendations for moisture management across the building’s entire lifecycle – from initial assessment and design to construction and ongoing use.
Going beyond condensation, BS 5250:2021 also encourages us to consider other sources of moisture affecting buildings, such as wind-driven rain and rising damp.
Joint Position Statement on Moisture in Traditional Buildings
If you deal with damp in traditional buildings, you’ll also need to consider the Joint Position Statement (JPS), co-written by our Professor John Edwards and supported by organisations such as RICS and Historic Scotland.
The JPS advocates a diagnostic process for correctly identifying the cause of dampness in traditional buildings, recognising that they behave differently from modern construction. This approach emphasises the importance of investigation before intervention, ensuring any remedial work is effective, while protecting the integrity of the building.
Learn to Deal With Damp, Mould and Condensation in Buildings
As we’ve seen, while dampness is common in UK buildings, misdiagnosis or a lack of understanding of the cause of damp is also too frequent, failing to address the issue.
If you’re a landlord or building professional wanting to effectively deal with damp, understanding BS 5250:2021 and the Joint Position Statement is essential. To support you in this, we offer the Level 3 Award in Damp, Mould and Condensation in Buildings.
The only Level 3 Award dealing wth both BS 5250 and the JPS, our two-day course will also give you the qualification you need to recognise your experience in dealing with damp, mould and condensation, as well as the essential skills for effective treatment.
Find out more about the Level 3 Award in Damp, Mould and Condensation in Buildings, alongside the rest of our training courses on damp in buildings. Contact us for more information and support in choosing your next course.
