Damp proofing buildings
The term ‘damp proofing’ refers to types of moisture control that are applied to walls and floors to prevent damp from setting in or spreading in a building.
Damp problems are among the most frequent problems encountered in buildings, particularly older buildings which may have been constructed without a damp-proof membrane.
Damp may be apparent from:
- Damp patches.
- Mould growth.
- Mildew, salts, staining and 'tide marks'.
- Damage to surface finishes, such as blistering paint and bulging plaster.
- Corrosion and decay of the building fabric.
- Slip hazards.
- Frost damage.
- Poor performance of insulation.
- Damage to equipment, or electrical failure.
The most common causes of persistent damp in buildings are:
- Condensation (surface or interstitial).
- Rising damp.
- Penetrating damp.
The two most common damp proofing techniques are:
Installation of a damp-proof course. A damp-proof course is a barrier, usually formed by a membrane built into the walls of a property, typically 150 mm above ground level, to prevent damp rising through the walls. Damp-proof courses are now required in the construction of new buildings to prevent rising damp and in some situations to prevent penetrating damp.
Damp proof courses can also be retrofitted to existing buildings by the injection of water-repellent chemicals. Treatment generally also involves remedial work to any corroded or decayed elements of the building fabric, as well as hacking off and replacing existing plaster to a height of 1 m.
For more information, see Damp proof course.
Installation of a damp-proof membrane (DPM). Typically, a DPM is a polyethylene sheet laid under a concrete slab to prevent the concrete from transmitting moisture through capillary action.
For more information, see Damp proof membrane.
Other damp proofing techniques include:
- Integral damp proofing: Concrete production can involve the addition of materials to make it more impermeable.
- Surface coating: Waterproof surface materials can be used internally or externally, such as render or waterproof plaster.
- Cavity wall systems: A cavity separates the interior walls from the exterior walls.
- Pressure grouting: This can fill in cracks and joints in masonry.
- Colourless water-repellent treatments.
However, it is important to note that damp is often just a symptom of another problem in a building, such as a lack of ventilation, drainage problems, cracks in walls, missing tiles or leaking pipework. It is important therefore that the underlying problem is rectified before other treatments are applied.
[edit] Related articles on Designing Buildings
- An interview with Matthew Mallows - Surveyor at British Damp Proofing.
- Basement waterproofing.
- Bitumen.
- Building damp-free cavity walls.
- Condensation.
- Damp.
- Damp-proof course.
- Damp-proof membrane.
- Draught proofing.
- Electrical resistance meters.
- Humidity.
- Moisture.
- Moisture content.
- Mould growth.
- Penetrating damp.
- Rising damp.
- Spalling.
- Stain.
- Structural waterproofing consultant.
- Tanking.
- Types of damp-proof courses.
- Understanding dampness.
- Wall insulation and moisture risk.
- Water.
- Waterproofing.
Featured articles and news
Top 50 firms awarded 52bn of projects in the last year
New engineering data shows.
Enhancing construction site reporting efficiency
Through digitisation and the digital revolution.
Noise in the built environment
BSRIA guide TG 20/2021.
17,000 people suffer conditions as a result of exposure to excessive noise at work.
Turning down the noise: Auditory health
A pervasive risk with far-reaching consequences.
UK Construction Week, London is here !
Debuting major international pavilions and much more.
Getting the most out of heat pumps and heating
How heat pumps work and how they work best.
Plumbing and heating for successful retrofit and renovation
Low temperature underfloor systems and heat pumps.
Cost-of-living crisis and home improvement plans
Starting on the right footing and top tips for projects.
Delays on construction projects
Types, mitigation and the acceleration of works.
From Chaucer to Fawlty Towers.
Electrotechnical excellence, now open for entries.
Net zero electricity grids BSRIA guide NZG 5/2024
Outlining the changes needed to transition to net zero.
CIOB Global Student Challenge 2024
Universitas Indonesia wins for second year running.
ECA 2024 Apprentice of the Year Award
Entries open for submission until May 31.
Comments