Retain your timber retaining wall!

posted: 29/Feb/2016

You may have heard on the grapevine that residential timber retaining walls are “outlawed” because they cannot achieve the typical design life expectancy that requires a 60 year target life expectancy.

Construction Timbers in Queensland (CTIQ) classifies retaining walls as either non-structural (moderate importance) with 15 year target life or structural (high importance) with a 50 year target design life and further and further clarifies the intent as follows:-

 “For the purposes of retaining walls:

(a) ‘moderate importance’ means anything other than ‘high importance’
(b) ‘high importance’ means retaining walls:
(i) where the total height of the wall and or the fill or cut retained by the wall is greater than 2m,
       or
(ii) that provide support to a building and structures such as an in-ground swimming pool, carport, garage or a deck more than 1 m above ground level beneath, where these buildings or structures are not supported by other independent means such as piers and the like that extend beyond the zone of influence of the retaining wall, or
(iii) that support another retaining wall described in (i) or (ii) above.”

In conclusion: if a wall of correctly specified timber is compliant with CTIQ requirements, it can fulfil this 50 to 60 year performance expectation.

For more information ask your local Accredited Queensland Merchant Network member for a copy of Timber Queensland Techncial Data Sheet #9 - Timber Retaining Walls for Residential Applications.

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