What is Damp Prevention?
Damp prevention, also known as damp proofing, is the process of protecting structures from the damaging effects of moisture. It focuses on preventing soil moisture from entering building foundations and walls. This is different from waterproofing, which protects against both moisture and liquid water.
Several methods effectively prevent dampness:
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Damp-proof course (DPC): A barrier, typically an impervious material like asphalt or plastic sheeting, is integrated into the structure (e.g., a brick wall) to block capillary action—the upward movement of moisture through porous materials. A common placement is 150 mm above ground level. (Reference: Integral Damp Proof Systems)
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Damp-proof membranes/sheeting: Durable, waterproof membranes are placed to prevent water and vapor from rising through walls. (Reference: Watertight Homes)
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Damp-proofing coatings: These are applied to surfaces to create a moisture-resistant barrier. Examples include asphalt emulsions, and specialized coatings like Henry's 789 Fibered Asphalt Emulsion or DECO 20 Dampproof Coating. (References: Henry, Deco Products, Polyguard) These coatings cure to a specific thickness, preventing the wicking (seeping) of water into the foundation. (Reference: Polyguard)
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Proper drainage: Effective drainage systems around the foundation divert water away from the building, reducing contact with walls and preventing water penetration. (Multiple References: Various sources highlight the importance of drainage for damp prevention.)
Damp Proofing vs. Waterproofing
It's crucial to differentiate damp proofing from waterproofing. Damp proofing addresses soil moisture, whereas waterproofing protects against both soil moisture and liquid water. (References: Concrete Network, Polyguard, Precast.org) Damp proofing acts as a long-term preventative measure against moisture decay. (Reference: Swenson Granite)
Practical Examples
- Basements are particularly susceptible to dampness; employing a combination of DPC and a damp-proofing coating can effectively minimize moisture issues.
- In areas with high water tables, installing proper drainage and a robust DPC are vital for preventing rising damp.
