The house itself was of unsurfaced redwood, battened with lath to keep out the winter rain.
"come to the surface," 1898, from surface (n.). Earlier it meant "bring to the surface" (1885), and "to give something a polished surface" (1778). Related: Surfaced; surfacing.
surface sur·face (sûr'fəs)
The outer or topmost part of a solid structure.
A certainty, esp a bet that one cannot lose: His election is a sure thing, right? (1836+)