NASCLA Accredited Commercial General ContractorThermal and Moisture ProtectionMedium
A commercial building's foundation walls are being prepared for dampproofing. The soil surrounding the foundation is known to have a high water table and occasional hydrostatic pressure. Which type of protection is required in addition to standard dampproofing to prevent water ingress under these conditions?
- AAir barrier application
- BThermal insulation board
- CVapor barrier installation
- DWaterproofing system
Show answer & explanationAnswer & explanation
Correct answer: D. Waterproofing system
Dampproofing is designed to resist capillary action of moisture, not hydrostatic pressure. When high water tables and hydrostatic pressure are present, a full waterproofing system is necessary to prevent water from being forced through the foundation walls.
Why the other options are wrong
- A. Air barriers control air movement, which is not the primary concern for hydrostatic pressure.
- B. Thermal insulation improves energy efficiency but does not prevent water ingress from hydrostatic pressure.
- C. Vapor barriers control vapor diffusion, not bulk water or hydrostatic pressure.
Dampproofing vs. Waterproofing
Dampproofing resists capillary moisture movement, while waterproofing resists liquid water under hydrostatic pressure.
- Dampproofing is for less severe moisture conditions.
- Waterproofing forms a complete barrier against water.
- Choice depends on water table, soil conditions, and building use.
Memory trick: Below Ground: Damp for Capillary, Water for Pressure.