construction cost
Refers to the total expense of building or engineering work, including materials, labor, and equipment.
The construction cost of the new bridge was higher than expected.
We revised the design to keep construction costs down.
This tunnel cost about one billion yen to build.
The municipality revised its budget in order to raise the construction funds.
Construction costs are ballooning due to rising material prices.
建設費 covers construction expenses broadly, while 工費 often refers specifically to the cost of a particular engineering or manufacturing job.
工費 (construction cost) and 公費 (public funds) are pronounced identically but refer to completely different things, so context is essential.
Compound of 工 (こう, 'work, construction') and 費 (ひ, 'expense, cost').