Guidance Note: Wooden Piling Or Foundation Poles Used For Permanent Buildings

This guidance note provides guidance to specifiers, designers, engineers, timber frame builders, or any other person or company regarding the correct use of treated timber poles for pilings or foundation poles in permanent buildings.

Piling is the term used for wooden poles used as load bearing foundation poles or posts and which forms part of the support frame of the substructure on which the main building or permanent structure is built.

1. Background and purpose

H4 treated wooden poles are used in most normal ground contact applications in South Africa. According to the SANS 457-2 (Softwood species) and SANS 457-3 (Hardwood species) standards, the expected service life of timber used in ground contact should be at least 20 years or longer if treated and used correctly. However, in the case of a permanent timber building the required lifespan should be in excess of the minimum period given in the standards, and in all likelihood should be equal to the expected lifespan of any normal brick and mortar house if maintained accordingly.

This Guidance Note provides guidance to specifiers, designers, engineers, timber frame builders, or any other person or company regarding the correct use of treated timber poles for pilings or foundation poles in permanent buildings. This note gives information on the correct Hazard Class treatment needed for such poles as well as a remedial inspection and maintenance treatment program to be implemented by the relevant and applicable parties after installation. This note is in addition to and supports of all the requirements already specified in the relevant and applicable national and compulsory standards as well as the regulations related to the compliance and use of preservative treated timber.

2. Definitions

Permanent building

A building in which people live, work or gather for leisure activities.

Piling

Wooden poles used as load bearing foundation poles or posts and which forms part of the support frame of the substructure on which the main building or permanent structure is built.

Primary preservative treatment

The preservative treatment of timber with an industrial type wood preservative in accordance with the approved impregnation processes specified in SANS 10005 to the applicable retention and penetration requirements specified in the relevant SANS wooden pole product specifications.

Remedial and supplemental treatment

A secondary preservative treatment applied to primary preservative treated timber that has been in-ground contact use for some years to augment and supplement the initial primary treatment and to prevent or remedy incipient fungal decay or subterranean termites attack at the ground line area.

3. Selection of the correct and appropriately treated timber material for use as piling

Only SANS 457-2 or SANS 457-3 poles shall be used. The use of SANS 1288 machine turned softwood poles shall not be allowed.

H5 treated poles: Only H5 treated poles shall be used for piling.

The tables in SANS national standards that give the penetration and retention requirements for preservative treated timber and poles, lists poles used as piling under hazard class H5 with the following footnote:

  • Due to preservative treatment requirements, all piling that is to be used in direct contact with the ground or that will be constantly or periodically in contact with fresh water or heavy wet soils (or both), shall be treated and marked in accordance with hazard class H5. All piling that will be in contact with estuarine or sea water shall be treated and marked in accordance with hazard class H6.

The rational for specifying at least a H5 treatment for piling to be used in ground contact is because of the permanence or long term service life required as well as the critical function that pilings have to fulfill.

H4 treated poles: In cases where H4 treated poles have been used for piling instead of the required H5 treated poles, a remedial and supplemental treatment program shall be implemented to ensure that the required lifespan or service life of such poles is achieved (See Section 4 below for details).

Note: The implementation of a remedial inspection and maintenance treatment program with the aim to augment and supplement the initial primary treatment of H4 treated poles should not be regarded as an alternative to the correct use and application of H5 treated poles but as an option to remedy H4 treated poles already in use as piling and to maintain the remedial action on an ongoing basis.

4. Implementation of an ongoing remedial inspection and maintenance treatment program for H4 treated piling in service

The remedial inspection and maintenance treatment program shall consist of periodic surveillance inspections done by a qualified remedial inspection and treatment person or company to assess the soundness of H4 treated poles and posts used as piling in ground contact. Should any signs of incipient fungal decay or subterranean termite activity be found, remedial and supplemental preservatives shall be applied to stop and prevent further degradation at the ground line area of such poles and posts.

Initial inspection of H4 treated wooden piling shall commence at 5 years, and not more than 10 years, after installation. Thereafter, follow-up surveillance inspections and remedial and supplemental treatment, as and when required, shall be done on a 5 yearly cycle.

Please contact SAWPA for more information on the recommended remedial and supplemental treatment products available as well as qualified companies that can do the remedial inspection and maintenance treatment, or where training can be done to qualify for inspection and assessment of poles used for piling as well as the correct application of remedial and supplemental treatment chemicals.



Latest


25 Mar 2021
Lanseria Smart City unlikely to make a big splash in SA’s urban landscape

In his State of the Nation Address on 13 February, President Cyril Ramaphosa revealed that the proposed Lanseria Smart City…

Lanseria Smart City unlikely to make a big splash in SA’s urban landscape

In his State of the Nation Address on 13 February, President Cyril Ramaphosa revealed that the proposed Lanseria Smart City “is now a reality in the making”, with the draft masterplan completed in November 2020 out for public comment. With South African cities and towns fast deteriorating at an infrastructure…

25 Mar 2021
Smart cities promote best practice in urban sustainability

A ‘smart city’ is much more than a city that is digitally enabled and brimming with technology. It is a…

Smart cities promote best practice in urban sustainability

A ‘smart city’ is much more than a city that is digitally enabled and brimming with technology. It is a city that leverages innovation to achieve its desired outcomes – and here innovation does not necessarily mean only technology. This is the view of Carshif Talip, Expertise Leader, Urban Planning…

24 Mar 2021
Pratliperl® revolutionises eco construction industry

Energy efficiency in the construction industry is more important than ever due to load-shedding and the rising cost of electricity.…

Pratliperl® revolutionises eco construction industry

Energy efficiency in the construction industry is more important than ever due to load-shedding and the rising cost of electricity. The thermal insulation of a two-leaf (220 mm) brick wall can be doubled, for example, by simply plastering the inside and outside with Pratley’s Pratliperl®. Pratliperl® is derived from a volcanic…

23 Mar 2021
Sunridge brings the Borras brand to South Africa

Sunridge Importers and Wholesalers, the distributing agent for a range of plumbing and hardware wholesale industry products, has secured the agency…

Sunridge brings the Borras brand to South Africa

Sunridge Importers and Wholesalers, the distributing agent for a range of plumbing and hardware wholesale industry products, has secured the agency and exclusive distribution rights for the Borras brand of taps and mixers in South Africa and neighbouring territories. Sunridge’s existing products include Rifeng, a patented multi-layered piping system produced in…


Top stories


09 Sep 2020
Dulux Unearths Courage as the 2021 Colour of the Year

Dulux, manufactured by AkzoNobel, this week launched its Colour FuturesTM 2021 palettes to set the tone for the year ahead. After…

Dulux Unearths Courage as the 2021 Colour of the Year

Dulux, manufactured by AkzoNobel, this week launched its Colour FuturesTM 2021 palettes to set the tone for the year ahead. After extensive trend research by AkzoNobel and external experts around the world, Brave Ground has been revealed by AkzoNobel’s Colour FuturesTM – as the Colour of the Year for 2021. The colour…

21 Aug 2020
The Condensed Suburb

Prior to the discovery of gold on the Witwatersrand in 1886, the Johannesburg suburb of Melrose was part of one of the…

The Condensed Suburb

Prior to the discovery of gold on the Witwatersrand in 1886, the Johannesburg suburb of Melrose was part of one of the original farms that made up the city. The suburb had its beginning when one of the original randlords bought land in the north of Johannesburg in 1893. He built his home there…

26 Mar 2020
5 000 Designs To Make Construction More Sustainable

The 6th International LafargeHolcim Awards for projects and visions in sustainable construction attracted almost 5,000 entries by authors in 121…

5 000 Designs To Make Construction More Sustainable

The 6th International LafargeHolcim Awards for projects and visions in sustainable construction attracted almost 5,000 entries by authors in 121 countries. More than 40% of the projects were submitted in the Next Generation category for students and professionals up to 30 years of age.

23 Mar 2020
Co-working Office Supports Local Design

  By some estimates South Africa’s cultural and creative industries contribute around R63 billion per year to the economy (approximately 1.7%…

Co-working Office Supports Local Design

  By some estimates South Africa’s cultural and creative industries contribute around R63 billion per year to the economy (approximately 1.7% of total GDP). South African born co-working office space provider Workshop17 believes that the rapidly growing flexible office industry can do more to support the local creative economy.


Visit the official COVID-19 government website to stay informed: sacoronavirus.co.za