Start from built area, not plot area
The first step in a sound estimate is using the actual built area from the drawings, not the plot area. The larger the built area, the higher the total cost, and confusing the two is one of the most common estimating errors.
The factors that drive cost
- Service scope: shell costs less than finishing, and turnkey delivery is the most expensive
- Finish level: economy, standard, premium, luxury — with wide gaps between them
- Design complexity: unconventional facades and large open spaces add cost
- Basement: adds excavation, waterproofing, structural work, ventilation, and drainage
- Lift and pool: each adds structural, electrical, and mechanical work
- Number of floors and foundation type, which depends on the soil study
- Site works: walls, entrances, and landscaping
The cost stages
Construction cost usually breaks into three stages:
- Shell (structure): excavation, foundations, columns, beams, and slabs; its cost depends on the design, foundation type, steel and concrete quantities, and soil conditions
- Finishing: often the largest variable, rising from economy to luxury with material quality and detail
- Turnkey: full delivery including finishing and systems
Jeddah-specific considerations
Jeddah's coastal climate adds considerations: humidity, salinity, and groundwater levels can affect foundations, waterproofing, and material choices. In some areas a high groundwater table can raise basement costs, so prioritising the soil and water survey early is wise. Material and labour prices may also vary with local supply chains.
How to estimate smartly
- Approve the drawings before construction to avoid costly mid-build changes
- Set the finish level early
- Compare quotes only when they cover the same specifications and scope
- Prepare a clear bill of quantities
- Keep a contingency reserve for changes and emergencies
- Clarify whether the quote includes design, permits, or the land
Preliminary estimates are useful for the big picture, but they stay approximate. The precise figure comes after the architectural, structural, and MEP drawings, the soil study, and the bill of quantities are complete.