Remediation details: inadequate ground clearance

Sometimes, the base of a wall and therefore the wall cladding is too close to the outside ground level, paving or deck surface. In some cases, the outside level is higher than the floor level inside.

Causes

Insufficient ground clearance can be caused by one or more of:

  • insufficient clearance when originally built
  • insufficient step-down onto a deck surface when built
  • paving or tiles being added to a deck surface later
  • outside ground level being built up during landscaping work
  • construction of driveways and paths alongside the building.
    Finished slab below ground level. The set-out of the slab levels for this building means that the finished slab is below the natural ground level around half of the building perimeter..

    Finished slab below ground level. The set-out of the slab levels for this building means that the finished slab is below the natural ground level around half of the building perimeter.

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    Where natural ground levels are too high

    Remediation options where outside natural ground levels are too high include the following:

    • Excavate to lower the level and slope the ground away from the building. This is the preferred option. Specifying that ground levels be lowered before remediating wall cladding is recommended, as it makes the cladding remediation easier and the cladding less liable to damage. The depth of underground services needs to be checked to see if this is viable.
    • Remove the cladding, the bottom plate and a portion of the bottom of the wall framing and form a concrete nib on the slab. Once the nib has been constructed, new bottom plates can be inserted (see figures below).
    • Construct drainage channels draining to the stormwater system. Note that, to be effective, drainage channels must be cleared.

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    Paving or decks

    Where there is paving around the base of the wall, the repair options will depend on the construction used and whether the outside level will be lowered. 

    Where decks are constructed from timber, the deck structure can be lowered and reframed.

    Where there is a concrete slab that is continuous under the dwelling and the outdoor living areas, there is a limit on how much the outside level can be lowered. Where this occurs, the repair option may be to construct a nib as shown above and in the case study below.

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    Dealing with the base of the wall

    Wall cladding must be installed so that it is clear of surrounding surfaces. For most claddings, this is necessary to ensure the durability of the cladding; it is particularly important for claddings installed with a drained and vented cavity. The figures below show options for ensuring there is sufficient clearance at the base of the cladding.

    Where the base of the cladding finishes immediately above or within a damp space, such as below a timber-slatted deck, consider terminating the cavity above the deck where the environment is drier. This minimises the risk of moist air being drawn into the cavity. Alternatively, consider adding drainage channels around the base of wall.

Updated: 9 September 2014