underdraw

[ uhn-der-draw ]
/ ˌʌn dərˈdrɔ /

verb (used with object), un·der·drew, un·der·drawn, un·der·draw·ing.

to line the underside of (a structure, as a floor) with plasterwork, boarding, or the like.

Origin of underdraw

First recorded in 1790–1800; under- + draw