PurposeThe purpose of this study was to determine the transaction cost (TC) contractors incur when tendering for a project as well as establish a correlation between the TC of tender and tender amount of projects procured through the national competitive bidding procurement method.Design/methodology/approachThe research draws extensively documentary analysis, observation and interviews to collect cost data on 14 different tenders submitted by a D1/K1 contractor. Using TC theory, the data are analyzed and the actual cost is determined. Further, Spearman rank correlation is employed to establish a relationship between tender price (TP) and the cost of tender by the aid of Statistical Package for Social Sciences.FindingsThe research developed a tender preparation conceptual framework highlighting the components of TC in competitive tendering in Ghana and also revealed that, apart from the emotional and psychological costs, contractors in Ghana incur approximately Gh₵ 4,625 (US$ 925)–Gh₵ 2,520 (US$ 504) to prepare and submit a competitive tender. In relation to the tender figure, the TC of tender in Ghana ranges from 0.05% to 0.65% and an average of 0.33%. Also, there is an inverse correlation between TP and the percentage cost of tender.Research limitations/implicationsThe research relied on 14 competitive tenders and also limited to public sector works. Findings from the study should therefore be applied with caution.Originality/valueThis study is the only known research that has focused on assessing the TC of public sector competitive tendering from a contractor's perspective and within a developing sub-Saharan African context.

Purpose Over dependence on river/sea sand as building material has impacted the environment negatively. However, laterite, which is an environment-friendly indigenous building material in sub-Saharan Africa, has been less exploited as a suitable alternative. This paper aims to ascertain the optimum cement–laterite mix proportion at which laterite can be stabilized for production of walling units. Design/methodology/approach Using an experimental method, laterite was collected from three borrow pit sites. Sieve analysis was performed to determine the particle size distribution. Also, the degree of workability of the cement–laterite mix was ascertained using slump test. Compressive strengths were determined at cement stabilization percentages of 3%, 7% and 10% on 12 cubes of100 mm cast and cured for 14 and 28 days, respectively. Findings The results showed that the lateritic soil investigated, achieves its optimum strength in 28 days of curing, at a stabilization level of 10%. An average compressive strength of 2.41 N/mm2, which is 20.5% greater than the target strength, was achieved. Practical implications To meet the desired compressive strength of alternative walling units while achieving environmental sustainability and efficiency in production, cement stabilization of lateritic soils should become a recommended practice by built environment professionals in sub-Saharan Africa. Originality/value This paper is one of the first research works that attempts to determine the optimum level at which the abundant sub-Saharan laterite can be chemically stabilized for the production of non-load bearing walling units. This research promotes an environment-friendly alternative building material to sea sand, river sand and off-shore sand.