It can be, it just depends on where it is in the sentence. ex:
Subject:
The building is tall.
Verb:
I am building a time machine.
"building a building' is not a sentence, it's a sentence fragment. Completing a sentence by adding a subject and auxiliary verb: He is building a building. Example as a noun clause as the sentence subject: Building a building is expensive. Example as a noun clause as the object of a preposition: He plans on building a building.
Richard Llewelyn-Davies has written: 'Building elements' -- subject(s): Building 'Building elements' 'Hospital planning and administration' 'Hospital planning and administration' -- subject(s): Hospitals, Construction, Administration 'Building elements' -- subject(s): Building
Henry Adams has written: 'The mechanics of building construction' -- subject(s): Building, Structural analysis (Engineering) 'Practical surveying and elementary geodesy' -- subject(s): Geodesy, Surveying 'Cassell's engineers' handbook' 'Building construction' -- subject(s): Building 'Notes in mechanical engineering' -- subject(s): Mechanical engineering 'Designing ironwork' -- subject(s): Iron and steel Building 'Theory and practice in designing' -- subject(s): Strains and stresses, Structural analysis (Engineering), Trusses
Geoffrey Hewland Hutton has written: 'Value in building' -- subject(s): Building, Estimates, Real property, Valuation 'Computer programs for the building industry' -- subject(s): Building, Computer programs
Scott Parish has written: 'National Building Code Compliance Manual' 'BOCA, national building code compliance manual' -- subject- s -: Building laws 'Uniform building code compliance manual' -- subject- s -: Building laws
steppted out of the building after ten minutes'
building co strution is core subject of civil engineer . In this subject civil engineer student know the knowledge of construction work.
R. Wendehorst has written: 'Baustoffkunde' -- subject(s): Building materials 'Bautechnische Zahlentafeln' -- subject(s): Building, Tables
(The) members = subject visited = verb
Kurt Brandle has written: 'The systems approach to building' -- subject(s): Building, Study and teaching, Industrialized building
Dieter Arnold has written: 'Building in Egypt' -- subject(s): Building, Stone, Egypt, History, Stone Building
I. N. Duncan Wallace has written: 'Construction contracts' -- subject(s): Building, International law, Contracts and specification 'Hudson's building and engineering contracts' -- subject(s): Building, Contracts and specifications