Ground Clearance
Clearance is required between the bottom of profiled metal cladding and large flat surfaces. For timber-framed dwellings, E2/AS1 requires a clearance of 35 mm to an adjacent roof, 100 mm to paved ground, and 175 mm to unpaved ground.
A printable bulletin is available at: BGC01 Pre-Painted Metal Wall Cladding to Ground Clearance
Extract:
"..Durability, rather than weatherproofness, motivates these clearances. The purpose of clearance
between cladding and ground surfaces is to keep the wall cladding free from build-up of vegetation or
debris, that may both be corrosive and increase time of wetness..."
The clearance requirements for unlined buildings are less than those required for lined buildings, as the absence of lining enables the inner face of the cladding to dry more rapidly, and inspection and maintenance of the framing can be practically achieved.
Importance Levels from NZS 3604:2011 (Table 1.1)
| Level 1 | Structures presenting a low degree of hazard to life and other property |
|---|---|
| Level 2 | Normal structures and structures not in other importance levels |
| Level 3 | Structures that may contain people in crowds or contents of high value to the community, or may pose risks to people in crowds. |
| Level 4 | Structures with special post-disaster functions. |
Minimum Ground Clearance for Lined Buildings
| Minimum Design Ground Clearance for Profiled Metal Cladding on Lined Buildings of Importance Level 2. | ||
|---|---|---|
| Ground Type | Minimum Clearance | |
| Garage door opening | 25 mm | |
| Walls under canopies | 35 mm | |
| Paved | 100 mm | |
| Unpaved gravel | 125 mm | |
| Unpaved lawn | 150 mm | |
| Unpaved pasture | 175 mm | |
Importance level 1 buildings may have a lesser clearance provided occupant maintenance prevents the build-up of debris against the cladding.
Greater clearance may be required where gardens abut a wall, where lawn grasses are not grazed or maintained, or where soil spillage from adjacent banks may occur. Future landscaping effects on ground levels must also be considered.
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