Construction is the process of building or assembling of infrastructure either for residential, industrial, commercial or heavy civic activities. It is a major factor in the development of different socio-economic sectors. For the successful execution of a project, effective planning in terms of the project lifespan, the environmental impact of the project, the safety level at the construction site, availability of building materials and most importantly the cost of executing the project are all essential. Cost estimation is a well-formulated prediction of the probable construction cost of a specific building project. A number of projects have been abandoned while others were completed haphazardly, due to improper cost estimations which sometimes lead to the collapse of some buildings. This research investigates and assesses how a simulated expert system can ensure a faster, more efficient prediction of the probable construction cost of a specific building project taking into account the following parameters: current market prices of building materials, labour cost and dimensions of the proposed building. In addition, the waterfall software development methodology was adopted in building the software. Results obtained showed that proper cost estimation of projects can be achieved with minimal tendency for errors.