Let’s Talk NHBRC

In this article we will start to cover the technical aspects as required by the NHBRC “HOME BUILDERS MANUALS” as well as “SABS 0400 (SANS 10400 is not yet published)

The most common challenges, resulting in Non-Compliances, which occur during the earth works stages of construction, are as follow.

Earth Works:

1. All plant matter and top soil under slab on ground must be properly removed from the building area for at least 1,5 meter outside of the perimeter of the building.
2. Trees that fall within the distances, to units, walls and drains to be constructed, as given in the NHBRC Home Building Manual Part 3, Section 2, Table 1 must be removed totally and the excavations backfilled with controlled fill. If the site soil classification is H1, 2 or 3 refer to Clause 2.4.1 of the Home Building Manual. In the event that the design of the house is as such, that it will be built around a tree or trees or if it is a regulation of the complex, estate or owner request that trees within the parameters must stay the following must be adhered to. NHBRC must be supplied with a Pro-Forma B1 and D1, RD1 issued by a registered competent person, with an NHBRC barcode, to confirm that such vegetation will not affect the integrity of the structure.
3. Bottom of foundation excavations must always be a minimum of 400mm deep (strip footings) and 300mm deep (slab-on-ground foundations) below natural ground level, and level not at an angle (this is not applicable for foundations on solid rock founding’s which require dowels as designed by a competent person)
4. Steps in excavations (foundations) are not allowed within 1m from corners or intersections unless so designed by a competent person.
5. All foundation excavations must be protected from storm water entering the excavations and kept dry at all times. Site storm water needs to be managed and maintained throughout the construction period.
6. It is highly recommended that the treatment of soil against subterranean termites (white-ants) be done by a registered member of SAPCA (S.A. Pest Control Association). As Chlordane and DDT is now a banned substance there is no product available on the market that will offer a 10 year guarantee and is the norm 5 years. Do insist on a guarantee for no less than 5 years. At present there is no approved product on the market for less the R10 per Lm/Sqm.  All products that are to be used for this application should be approved under SABS code of practice 0124. Poisons like chlorpyrifos, etc. is not suitable for this application. SAPCA can be contacted on 0861114556.
7. After backfilling around foundation structures the surrounding area must be shaped to drain off storm water for at least 1,5m from the perimeter of the building.
8. Fill under slabs that exceeds 400mm deep must be certified by a competent person.
9. A polyethylene under floor membrane, of no less then, 25mm (250 micron), must be placed, in accordance with the manufacturers laying instructions, under all slabs-on-fill or rafts. The most commonly used for this application is USB Green 250.

All pro-forma documents are available from Master Builders Kwazulu-Natal offices.

Brandon Abdinor | Executive Director