Source : Webster's Revised Unabridged Dictionary (1913)

Roof \Roof\, v. t. [imp. & p. p. {Roofed}; p. pr. & vb. n.
   {Roofing}.]
   1. To cover with a roof.

            I have not seen the remains of any Roman buildings
            that have not been roofed with vaults or arches.
                                                  --Addison.

   2. To inclose in a house; figuratively, to shelter.

            Here had we now our country's honor roofed. --Shak.

Roofing \Roof"ing\, n.
   1. The act of covering with a roof.

   2. The materials of which a roof is composed; materials for a
      roof. --Gwilt.

   3. Hence, the roof itself; figuratively, shelter. ``Fit
      roofing gave.'' --Southey.

   4. (Mining) The wedging, as of a horse or car, against the
      top of an underground passage. --Raymond.

Source : WordNet®

roofing
     n 1: material used to construct a roof
     2: the craft of a roofer