Architectural Design
January 15, 2024
The shell phase is the most critical and least reversible stage of construction. Accurate cost planning for this item maintains budget discipline throughout the project.
What Is Shell Construction?
Shell construction encompasses all work that forms the load-bearing skeleton of a building: site preparation and excavation, foundation concrete, reinforced concrete column-beam-slab system, partition and load-bearing wall construction, roof structure and covering. When this phase is complete, the building has reached its raw form, ready for plastering, tiling, electrical and plumbing.
2025 Per-Square-Metre Costs
For Istanbul and surrounding provinces, 2025 data indicates: standard reinforced concrete shell (C25 concrete, B420 reinforcement, brick walls, tile roof) at 10,000–13,000 TRY/m²; multi-storey or special ground condition structures at 14,000–16,000 TRY/m²; structural steel buildings at 16,000–22,000 TRY/m². These prices exclude VAT.
Cost-Driving Factors
Poor ground conditions (soft, saturated or fill ground) can require piled foundations, raising cost by 15–30%. A basement adds significant cost through deeper excavation, waterproofing and formwork. Regional climate (frost depth, seismic zone) also affects structural system sizing and therefore cost. In high-seismic zones such as Istanbul, TBDY 2018 requires higher shear wall ratios, increasing the volume of reinforced concrete.
Quality Compromises to Avoid
The most common mistakes made under cost pressure in shell construction are: using under-grade concrete (C20 instead of the project-specified C25/C30), reducing reinforcement density, insufficient concrete cover and premature formwork removal. These errors directly threaten seismic safety and cannot be corrected after the fact. At Home Yapı Mühendislik, we work in parallel with the building inspection firm at every stage of the shell phase and have concrete samples independently tested in accredited laboratories.
General Contracting