Design changes to three new primary schools in Dumfries and Galloway are set to add £1.1m to the building costs.
The projects are part of the council's public private partnership schools modernisation programme.
The new designs are to be implemented at Heathhall, Castle Douglas and Kirkcudbright.
A council spokeswoman said the changes would allow the primary schools to achieve the "optimum solution" with the designs involved.
The first of the redesign plans is for the new Heathhall Primary in Dumfries and carries a price tag of a little more than £500,000.
The new blueprint is said to be radically different from the original - and will have to go through the planning process.
A revised site layout has been drawn up to take in additional land bought by the council.
The changes also include the construction of a new roundabout to improve traffic management and child safety.
The two other projects earmarked for design changes are Castle Douglas and Kirkcudbright primary schools.
The proposals carry a combined additional cost of a little less than £500,000.
The revised plans would see the construction of an additional classroom in each school.
Councillors sitting on the committee overseeing the PPP project will consider the proposed changes on Friday.