The new Habitat Resource and Development Centre in Katutura, Namibia, pushed the appointed quantity surveyors’ skills to the limits, posing the challenge of quantifying reclaimed and scrap material.
Quantity surveyors have fulfilled the roles of financial managers for building projects for centuries, but together with the green building movement came a new challenge of controlling costs for very unusual structures. One of these is a building designed by sustainability architect, Nina Maritz, for the new Habitat Resource and Development Centre in Katutura on the outskirts of the Namibian capital, Windhoek, which consists almost entirely of scrap materials.
Comprising offices, a library, a conversance centre, workshops and ablutions, the 2 110m² structure was built with alternative building techniques and many innovative and recycled materials. To ensure the building’s energy efficiency, a rooftop solar system was installed to supply all the required energy. A passive down-draft system cools the conversance facility, while natural light and cross-ventilation further reduce the structure’s electrical demand.
De Leeuw Namibia, a subsidiary of South African quantity surveyors, the De Leeuw Group, was appointed to manage the total financial process applicable to the building on behalf of the Namibian Ministry of Regional and Local Government, Housing and Rural Development.
Chris de Wet, chairman of the De Leeuw Group and former director of ASAQS, comments that the project posed the kind of challenge a quantity surveyor seldom has to face: Adherence to design while working with reclaimed material that had been destined for landfills or, in some cases, even physically retrieved from scrap heaps.
“Green building challenges the norm as never before, and calls for unique thinking from the entire project team. The quantity surveyor plays a leading role in estimating the costs and managing financial control. So, when faced with a green project like no other, even the most experienced quantity surveyor (QS) is literally thrown in the deep end with no previous records from which costing models could be drawn,” De Wet explains.
Skills pushed to the limit
Apart from the unusually high number of design changes, estimating the cost of the building materials on this project was extremely difficult due to the fact that scrap dealers sell to the first buyer, so by the time a contractor is appointed the selected materials may no longer be available. Also, since the government tender insisted on transparency, the awarding of tenders could not be based on selection or negotiations.
“We had to resort to informal discussions with contractors and trust our gut feeling of how much some of the materials would cost,” says Herman Martins, director of De Leeuw Namibia.
De Leeuw Namibia undertook weekly site visits to assess the unpredictable waste factor of some materials, and to establish if some of the waste could be re-used to minimise the financial impact. The concept of actual cost plus profit was employed for items such as old wheelbarrows which were cut in half, flattened and welded together to form screens.
The company also organised a special workshop for tenderers to provide and share as much information as possible between the various parties so that an acceptable bill of quantities (BOQ) could be drawn up.
Full thanks and acknowledgement are given to ASAQS for the information given to write this article.
1. Old tyres for interior and exterior walls, retaining walls, roads and flower beds.
2. Sandbags for wall building material.
3. Pre-owned hardware door and window frames, ironmongery and scrap sheeting for a variety of applications, including discarded fridge racks that form part of a decorative security gate.
4. Bags filled with wool and lavender, stitched together for an innovative wool and reed ceiling.
5. Bricks made from natural soil and as little cement as possible.
6. Recycled oil drums and dried branches of the Namibian prosopsis tree to make the roof of the centre’s refuse yards.
7. Gabion walls made from concrete test cubes, rubble and stone.
8. Droppers made from prosopsis tree trunks soaked in motor oil as protective coating.
9. Old beverage cans for single-skin walls.
10. Recycled ceramic tiles as ablution décor, motor car oil filters and old printing plates as lamp shades, and discarded CDs as part of lighting chandeliers.