Design Project Management in the Nigerian Construction Industry: Integrating Interior Design Workflows

Interior design project management within Nigeria's construction industry is characterised by fragmented workflows, inadequate design documentation standards, and unresolved professional boundary disputes between architects, interior designers, and contractors. This study examines design project management practices in the residential and commercial construction sector in Abuja and Lagos, with the aim of identifying systemic inefficiencies and developing practical management frameworks for interior design integration. Data collection involves structured interviews with thirty-eight project managers, eighteen interior designers, and twenty-two contractors, supplemented by document analysis of project specifications, change order records, and completion audit reports from twelve recently completed construction projects. Findings show that design scope changes arising from late-stage interior design inputs account for an average of twenty-two percent of project cost overruns across the sampled projects. The absence of standardised interior design deliverable schedules that align with construction project phasing is identified as the primary structural cause of these overruns. The study develops a Design Integration Schedule for the Nigerian Construction Context, specifying interior design deliverable milestones that correspond to standard construction programme milestones from concept approval through to practical completion. The Schedule is validated by a panel of fifteen industry practitioners from both design and construction disciplines. Recommendations include professional training in design project management for junior interior designers, and the adoption of the Schedule by the Association of Professional Women Engineers and Scientists in Nigeria and the Nigerian Institute of Interior Design. Keywords: design project management, interior design, construction industry, Nigeria, workflow integration.