New face planned for a dated D.C. office building with a prime address. And the retail arcade? That's gone.

The Mills Building at 1700 Pennsylvania Ave. NW is a vestige of planning days long gone by, with a facade dominated by large sections of precast concrete and a retail arcade that sets back storefronts far from the street.

Akridge, on half of the building’s longtime owner, has filed plans with the District to modernize this 52-year-old, 10-story property, which sits in the shadow of the Old Executive Office Building and Renwick Gallery, to possibly add multiple stories and overclad the façade…