We can estimate how far down the old surface used to be.

In the summer of 1998 the old surface was replaced with a new one.

Be sure to follow directions on the package and to clean the old surfaces thoroughly beforehand.

Before repainting these sections, be sure to clean and sand the old surface.

The company that installed the 5 year old surface went out of business and was not available to maintain the worn surface.

They were bright where the sharp steel had sheared them, dull on the older surfaces.

Mars has an old surface compared to Earth.

This means making sure the old surface is clean.

Its nature is presently unknown; it may be an old basaltic surface.

The underlayment will prevent irregularities in the old surface from showing through the new one.