Revised standard includes tree effect Australian Standard, AS 2870-2011
Residential slabs and footings , extract

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What does this mean;

The depth of a Root barrier/moisture cutoff wall for protecting foundations
is determined by the soil test data, and depths of two, three and four metres are not unusual.
Please call me on 1300 136644 for more information.
Alan Coulton, Root Barrier

MATRIC SUCTION, WHAT IS IT?

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Matric suction is the pressure dry soil exerts on the surrounding soils to equalise the moisture content in the overall block of soil.

Matric suction conditions in the soil profile were obtained through steady state unsaturated seepage analyses. The initial matric suction profile is the same as suction varied from 409 kPa at tree root to 49 kPa at lower boundary of the
soil domain. The contours of changes in matric suction are presented in Fig. 11. The closer to the tree, the more change in suction is observed. The results of stress-deformation analysis are shown in Fig 14 as contours of vertical
displacement. A maximum foundation settlement of 80mm and minimum settlement of 25 mm was observed. A maximum settlement in the soil profile took place at tree location and decrease with horizontal distance and depth.

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Root Barrier is locally produced to suit Australian conditions, stock is on hand and available.

Good service, good prices, sound advice and a happy disposition make work an enjoyable place to be.

HOW DO WE MINIMISE THE SHRINKAGE OF REACTIVE CLAY?

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By placing a 1.5 to 2 metre root proof and waterproof wall around the structure that we wish to protect. This will create a island effect and keep the change in moisture content to a minimum. Root barrier will effectively disconnect the tree from the moisture under the slab.

ROOT BARRIER is a flexible waterproof cutoff wall which will achieve both goals of
stabilising the clay an keeping the tree roots away.

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