A five-year plan adopted by the city in 2004 to expand and upgrade its schools has become more expensive and has progressed at a slower pace than originally was estimated, according to a report by a nonpartisan organization that analyzes city government finances, the Independent Budget Office.

The five-year capital plan, which includes the construction of new schools, upgrading existing facilities, and implementing new educational programs, will cost $13.4 billion, up $227 million from the original budget.

Rising construction costs citywide and new environmental regulations, such as the 2007 Green Building Law, which requires that new city buildings meet certain conservation standards, have contributed to the budget issues, the report says.

Surging demand for construction work has pushed up bidders’ prices on contracts some 45.7% on average since the plan was first proposed. As a result, the latest amended capital plan now allocates $2.4 billion for constructing and leasing new school space, as opposed to the original version’s $1.8 billion. The average time needed to complete the 42 expansion projects has increased by six months, to about 3 1/2 years a project.

The higher costs are being borne mostly at the expense of a series of education initiatives designed by Chancellor Joel Klein, such as adding new technology to classrooms and dividing up large high schools into multiple smaller ones. These programs have seen their budget drop to $2.47 billion from $3.84 billion in the original 2004 plan, a 36% decrease.