With over 3.5 billion people connected to the internet, small and medium-scale (SME) construction businesses have the opportunity to enhance their customer base. The study assessed ways by which marketing functions of SME construction businesses can be improved through social media presence of the firms. The study used a quota-purposive sampling of construction businesses in Nigeria's mega city, Lagos State. The small and medium scale construction businesses comprised of consulting and contracting firms. Using a questionnaire instrument, the social media arm of the marketing unit of SME construction businesses was measured. Presentation of the data was carried out using pie charts and principal component analysis. The study identified two main critical success factors (CSFs) - Firm/Social Media characteristics and Security/Investment factor enabling the Social Media infrastructure for SME construction businesses. A focus on these entities would ensure the successful integration of social media marketing strategies in the traditional marketing functions of construction SMEs. The survival of SME construction business is hinged on the availability of customers which social media exposure helps attract and interact with potential customers. SME Construction businesses of the 21st century must align with the 'global village' trend of incorporating social media applications in their traditional marketing functions.