| Provisions | Limits on application |
| Objective | |
| E2.1 The objective of this provision is to safeguard people from illness or injury that could result from external moisture entering the building. | |
| Functional requirement | |
| E2.2 Buildings must be constructed to provide adequate resistance to penetration by, and the accumulation of, moisture from the outside. | Requirement E2.2 does not apply to buildings (for example, certain bus shelters, and certain buildings used for horticulture or for equipment for washing motor vehicles automatically) if moisture from the outside penetrating them, or accumulating within them, or both, is unlikely to impair significantly all or any of their amenity, durability, and stability. |
| Performance | |
| E2.3.1 Roofs must shed precipitated moisture. In locations subject to snowfalls, roofs must also shed melted snow. | |
| E2.3.2 Roofs and exterior walls must prevent the penetration of water that could cause undue dampness, damage to building elements, or both. | |
| E2.3.3 Walls, floors, and structural elements in contact with, or in close proximity to, the ground must not absorb or transmit moisture in quantities that could cause undue dampness, damage to building elements, or both. | |
| E2.3.4 Building elements susceptible to damage must be protected from the adverse effects of moisture entering the space below suspended floors. | |
| E2.3.5 Concealed spaces and cavities in buildings must be constructed in a way that prevents external moisture being accumulated or transferred and causing condensation, fungal growth, or the degradation of building elements. | |
| E2.3.6 Excess moisture present at the completion of construction must be capable of being dissipated without permanent damage to building elements. | |
| E2.3.7 Building elements must be constructed in a way that makes due allowance for the following: | |
| (a) the consequences of failure: | |
| (b) the effects of uncertainties resulting from construction or from the sequence in which different aspects of construction occur: | |
| (c) variation in the properties of materials and in the characteristics of the site. | |