Customer Protection Act (CPA)

Click here to download the Consumer Protection Act (CPA) documentation relating to ReMaCon Products.

 


09 September 2011

Consumer Protection Act (CPA)

What must “Concrete Retaining block” (CRB) manufacturers, their distributor and specialist installation contractors and be aware of and act upon, to ensure that the requirements of the CPA are met to avoid end user disputes.

The following guidelines must be explained to the end user;

  1. The end user must be given the basic information on the use and application of CRB’s as follows;

    1. The choice of block to be used must be determined not only by their cost and aesthetic appeal, but the end user must be made fully aware of whether the product actually caries the appropriate SABS mark in terms of “SANS 508 Concrete Retaining Blocks”, or a similar verification agency, or whether they do not. ReMaCon Products is the only CRB manufacturer in South Africa to carry the mark, see our SABS certificate.
    2. Retaining blocks are “active” structural elements, not “passive” like bricks and paving, that means that they are under pressure and strain all the time.
    3. The maximum height that is deemed “fit for purpose” in terms of the “National Building Regulations SABS 0400-1990”, is 1.4m for products that are least 200mm deep, without piers.
    4. Any sloped retaining wall that exceeds 1.5m should therefore be designed by an engineer.
    5. ReMaCon Products provide an in-house design service with full Professional Indemnity Insurance.
    6. CRB’s are mostly constructed at wall angles of 75 degrees or less, item (c) above applies, however certain CRB products can be constructed vertically, in that case if the height exceeds 900mm, an engineer’s design is required.
    7. Water drainage must be allowed for, both for surface running water as well as for sub – surface water, and engineers design will detail the drain required.
    8. Each retaining wall is different, soil types vary, water drainage problems are different, design slopes and surcharge loadings above vary (walls, roads, etc) , therefore each site should in terms of the SABS code of practice “SANS 207 The design and construction of reinforced soils and fills”, be inspected and appropriately designed for.
  2. What are the limitations of CRB’s;

    1. They are structural elements, not just landscaping afterthoughts, they must be designed correctly and then they can be beautifully landscaped and vegetated to cover the walls
    2. Wall heights of up to 10m with most CRB’S can be reached, but strictly by design only.
    3. We avoid “vertical” or 90 degree walls, we prefer “near vertical” walls of 86 degrees, that way any movement due to fill settlement will move the angle toward 90 degrees and not lean over.
    4. Construction of CRB’s can be undertaken as a DIY job, but only for wall heights less than 1.5m. It is strongly recommended that specialist contractors, preferably our own approved contractors, build walls higher than 1.5m. See our web site list of approved contractors.
    5. Irrigation must be installed correctly, do not place pipes immediately behind the tow row of wall blocks, rather set pipes back 1m to1.5m and spray over the wall, or place pipes below and spray upwards, or place pipes against the wall face, the vegetation will cover them. Leaking pipes above the wall will result in soil saturation that may result in the wall failing.
  3. Foundations;

    1. Excavate for foundations at least 250mm deep for walls < 1.5m high.
    2. As a rule of thumb only, sloped retaining block walls no higher than 1.5 m, only require a well compacted base at least 150mm deep x 500mmm wide, but it is best to add a 1x 50kg pocket of cement per every 7.5m length, into the loose soil, mix it in thoroughly, level and compact it.
    3. The first row of blocks should be at least 100mm below the ground, this acts as a “kicker” or “skopstut”
  4. Compaction of soil and what type of soil to use;

    1. Topsoil is only good to fill the voids inside the actual blocks with, it will help plants grow strongly.
    2. Soil behind the rear of the blocks should be granular, no clayey soil, and must be compacted with a hand tamper or by using mechanical compaction equipment.
    3. Soil must be damp or it will not compact. Dry soil and wet saturated soil will not compact, compost will not compact either, don’t use it behind the blocks, only inside them. If you have a heap of dry soil, it’s best to open up the top of heap, water generously, then leave overnight to soak. The next day it can be turned and ought to be sufficiently moist to compact well.
    4. Basic compaction density required is no less than 90% mod AASHTO. Compaction can be tested by Troxler and/or DCP methods using soils laboratories, but for walls < 1.5m high, a quick DIY test can be done by using a short 500mm length of 10mm Ø round bar with a rounded end, not a point, prod it into the compacted soil putting your body weight behind it, if it only penetrates 20mm to 50mm with difficulty and then refuses to go any deeper, the compaction is adequate, if it sinks in easily, your compaction is $&@*, do it again.
    5. Using rubble is possible, but the rubble size should be no more than ±100mm Ø, i.e half brick size, and must be mixed in with the soil to a proportion of no more than 1 part rubble to 3 parts soil.
  5. Drainage requirements:

    1. Surface water flow due mostly to storms, must be controlled by channelling it above and in some instanced below the wall, and guided to a controlled discharge point, ensuring no damage will occur at the discharge point.
    2. To take care of the unseen underground or sub-surface water, a drain usually consisting of an agricultural pipe with perforations, covered with stone and wrapped with a water transmissive geosynthetic fabric, placed one block above the ground level in front of the blocks, against the natural back face material, with outlets coming to the front face of the wall, is generally good practice. 
    3. It is critical that the all fill behind the block walls is kept as water free as possible, additional drainage measures may be required depending on the circumstances.
  6. What about building brick walls and placing palisades above retaining block walls?

    1. It is preferred that brick walls are built directly on above the top row of blocks, not behind them, the same applies to palisade fencing and balustrades.
    2. The wall foundation is cast into and between the two top rows of blocks, they should extend at least 300mm behind the rear of the blocks and should be reinforced with minimum Y10 steel, all to the engineer’s detail.
    3. Most CRB’s are hollow, so the palisade post foundation can be cast directly into the block voids.
  7. …and what about trees and plants?

    1. It is best that trees are not permitted to grow in between the wall blocks, because they will eventually break the blocks due to trunk growth size and due to wind action. Then when they die and the root ball rots, it forms a cavity and the wall could cave into itself.
    2. If a biggish tree is above the wall, check whether it is a “pilot” rooted tree, i.e. deep rooted, if not it’s best to either keep as far away from it as possible, or to remove it. Blue Gums / Eucalyptus trees are a definite no-no.
    3. Trees can grow in between the blocks in the wall, but they should be small type of trees, preferably shrubs should be planted. 
    4. It’s best to select indigenous plants to vegetate the walls with, they don’t require rich soil, nor much pampering, tolerate dry conditions and they attract the insects and birds to the garden.
    5. The Green Star Rating – whilst we do not have the official rating, our products comply fully with it.
  8. What about civil engineering structures higher than 10m?

    1. Our special product, the TW1, is available for railway, highway and bridge abutment loaded retaining structures for wall angles of 86 degrees.
      1. Designs with full Professional Indemnity can be undertaken by Tensartech International for consulting civil engineers
      2. The highest structure was built in Dubai in 2008 and 2009, and reached 60m total height in 3 terraced walls, the middle wall reached 22.5m height, at 86 degree angle. See the picture gallery.
      3. The walls are constructed with continuously moulded HDPE geogrid reinforced fill, using the Tensar RE500 series geogrids, suitable for 1% and 0.5% strains, per SANS 207.
    2. Attenuation pond walls need special attention and can be designed by ReMaCon Products – see the picture gallery.

  9. Product and design insurance ;

    1. ReMaCon Products have all the necessary insurance policies in place should anything beyond our control go wrong;
    2. Professional indemnity insurance for the structural design of CRB walls – a copy of the policy can be emailed.
    3. Product liability insurance for R20 000 000.00