A development cost comparison between a multi-storey mass timber and reinforced concrete building in South Africa

Abstract

High-rise timber buildings have experienced a resurgence internationally during the past two decades. This paper presents an investigation into the financial feasibility of a multi-storey mass timber building for South Africa through a development cost comparison. Two 8-storey commercial buildings - a mass timber frame and a reinforced concrete frame - were first designed by independent engineering consultants. A focus group workshop, conducted with industry professionals, assisted with the development of construction schedules. Subsequently, a financial model was developed to determine the overall development cost and financial feasibility of each option. Finally, a sensitivity analysis was conducted to investigate the effect of certain variables on the overall profitability of the mass timber frame development. The focus group workshop identified that the construction of the reinforced concrete frame building and mass timber frame building will take 42 weeks and 21 weeks, respectively. The total capital investment required for the mass timber frame development was found to be 10% more than that of the reinforced concrete frame development (R115 691 000 versus R 105 118 000). A five-year internal rate of return (IRR) of 20.9% and 25.7% was calculated for the mass timber and reinforced concrete frame developments, respectively. A significant finding of the sensitivity analysis was that the mass timber frame building proved to generate a higher five-year IRR than that of the reinforced concrete frame once the mass timber building achieved a rental premium of 7.8% or more. The sensitivity analysis further showed that the importation of the mass timber elements remains an expensive option, with a 16.4% five-year IRR for the imported mass timber frame (at a R17:€1 exchange rate).