President Trump is demanding that new sections of the border wall be painted black in a move that could add at least half a billion dollars to the cost of the project.

The new order comes after Trump told staff that he noticed that a black granite countertop at one of his golf courses got hot in the sun, leading him to think that a black wall would deter illegal border crossings and make the wall seem more imposing.

An administration official told the Washington Post that the additional costs to paint the new sections would range from $500 million for ceramic paint and up to $3 billion for powder coating, a process where paint is baked on to the materials.

The new wall sections are made of steel bollards or posts installed closely together so that wildlife can still pass but too close for humans. Critics have complained that the design still allows packages to be handed through the posts, and some newly installed sections have already been cut with small electric hand saws.

According to sources that spoke with the Washington Post, military and administration officials have tried to talk President Trump out of the new paint because it’s unnecessary and will add to ongoing maintenance costs, but Trump has insisted on the change. Painted section would need to be repainted and would require additional funding for maintenance. The current design consists of unpainted steel posts and plates.

The border wall project, a cornerstone of Trump’s campaign and presidency, has already been allocated $15 billion, mostly money that was diverted from military and counter-narcotics funds. Congress has only allocated $3.6 billion specifically for new wall contraction. So far, 175 miles have been completed.