Professional design service: call +27 021 465 1907 or email [email protected]

TERRASAFE wall design serviceProfessional service for Terraforce walls

We offer industry leading expertise as trusted advisors and apply customised approaches to enable clients to define strategies that will help them succeed.

What is Terrasafe about

Terrasafe provides first-class engineering, management, and specialist technical service to users of any of the Terraforce products. We aim to set industry standards and make a significant contribution throughout South Africa and the world.

More about Terrasafe and how it works:

Clients that wish to receive Terraforce wall designs need to provide following input regarding their requirements:

  1. Geotechnical report and/or density tests, if available.
  2. Photographs of the site.
  3. Completed Terraforce questionnaire for gravity, composite or terraced walls.
  4. Any information on previously proposed designs involving other methods.

After all requirements and technical data is processed and approved, the client will receive one or more cross section designs that can be applied to site. This approach has worked successfully for various projects, past and current, in South Africa and other countries.

As more and more clients requested provision of site supervision and professional indemnity insurance, Terrasafe added this additional service to its portfolio. The cost for the extra assistance will naturally be higher and is based on a percentage of the Terraforce project value. Currently it will only be available for installations that can feasibly be managed from Cape Town, but in time may be extended to other centres in South Africa and overseas, in association with engineers that are based near those sites.

Terrasafe has, and currently is, specifying Terraforce products for building sites in South Africa, Namibia, Swaziland, Chad, Australia, India, Spain, Canada, UAE, Qatar, Bahrain, and the U.K.

Quality Assurance

Terrasafe strives to provide on a continuous basis a quality, professional service and to add value to our clients’ projects.


Terraforce Products are regularly recognised by many independent industry and professional bodies as well as prestigious trade publications around the world in the form of coveted industry awards and articles. Our awards track record is a significant demonstration of our commitment to fostering achievement for our clients.

Advisory services

Terrasafe understands that there is often more to a project than delivering an engineering solution. Other key project elements include strategic planning, risk assessment and management, project development and supervision in co-operation with engineers in other parts of South Africa and wherever Terraforce products are sold.

Terrasafe’s advisory team has delivered quality services to various clients for more than 15 years. With a strong technical base and proven capability in project conception and delivery, Terrasafe provides clients with comprehensive support from the initial project planning phases through to managing the asset lifecycle.

We offer industry leading expertise as trusted advisors and apply customised approaches to enable clients to define strategies that will help them succeed.

Professional Indemnity Insurance

Terrasafe is fully covered by Professional Indemnity Insurance with Manwood Underwriters (Pty) Ltd, for projects, local and abroad to the value of R 2.0 million

Holger Rust, owner of Terraforce, Cape Town based pre-cast concrete licensor, specialising in modular, hollow core concrete blocks, is passionate about professional design:

“Right from the start, when Terraforce was founded in 1979, we have been involved in assisting specifiers with design services in the form of purpose made tables, design manuals, excel spreadsheets and a windows based design programme. Occasionally our engineer also provided a full design service, now and then including the supervision of the site, when requested to do so by the client.”

This dedication to professional services and the development of first-class products has paid off over the years, Terraforce products having become well known in many parts of the world. Of course, as Terraforce grew into a successful company, competitors started up in various corners of the country and while Holger agrees that competition should not be viewed as a threat, he feels that most people in business understand that, “competition is good for business and for the consumer, imitators and copycats are not.”

Holger adds that throughout the years a string of imitators, operating in many locations, came and went, leaving behind a trail of on-site disasters: “Lacking a sense of ethics and values, most of them are and where strangers to terms such as statutory requirements, surcharge loadings, potential failure planes, interface shear capacity, pull-out and crushing resistance, lateral earth pressure or progressive backfill erosion. The lack of any SABS/SANS standards at that stage made things even worse.”

Early in the 1990’s Terraforce, as a response to this situation, started a catalogue of failures with photos and investigation of causes. This collection was later adopted, with small changes, by the Concrete Manufacturers Association of South Africa (CMA). In short, the document cautions that due to insufficient professional design and supervision, segmented block retaining walls can occasionally suffer from these shortfalls:


a. Insufficient constructed mass – no or negligible design input.

b. Saturated backfill – lack of drainage above of behind the wall.

c. Design angle and height exceeded – lack of supervision.

d. Settlement of backfill – substandard material, inadequate compaction/backfill erosion.

e. Undermining – excavation close to wall foundations.

f. Excessive loading – not accounted for in the original design.

g. Limited bearing capacity – poor/saturated founding conditions or no foundation at all.

h. Face connection failure – poor connection between blocks and geo-grid.

i. Linear cracking of blocks – excessive lateral earth pressure or poor quality of blocks.

It is important to note, says Rust, that sometimes a combination of causes may be the trigger for these shortfalls.

In the absence of a ready-made SABS/SANS specification for concrete retaining blocks (CRB’s), Terraforce turned to the International Conference of Building Officials (ICBO) in California for a comprehensive evaluation report in compliance with NCMA specifications. Dr. Richard Bathurst in Kingston, Ontario conducted the necessary testing and with Colin Alston of Alston and Associates, compiled our latest design manual. “Over and above that we set up a number of recommended installers in all parts of South Africa. They have undertaken to guarantee their workmanship and undertake to follow our guidelines and standards”, says Holger.

He adds that these measures have to a degree put a damper on the scourge of sub-standard workmanship among some manufacturers and installers: “The various excellent publications distributed by the CMA over the years have also made a big difference. Recently an SABS/SANS (508/2008) standard has finally been published and will hopefully make a difference.”

Holger says that the recent spectacular failure of a large wall in Namibia (built by a competitor and brought down by lacking drainage after a storm) has prompted Terraforce to launch Terrasafe, “to protect our good reputation as best as we can.”

Designed by Terrasafe: Noisebarrier

Designed by Terrasafe: Noisebarrier

Same project shortly after completion

Same project shortly after completion

...the wall is hardly visible from the raod.

…the wall is hardly visible from the raod.

And three years later...

And three years later…

Designed by Terrasafe: Retaining wall at shopping mall

Designed by Terrasafe: Retaining wall at shopping mall

Designed by Terrasafe: Vertical composite wall in Canada

Designed by Terrasafe: Vertical composite wall in Canada

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