roof
noun
the external upper covering of a house or other building.
Used to describe an ongoing action or continuous state that was happening at a specific time in the past.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The barn was now up, and the carpenters were roofing it in, while two days more of work would complete the sty and poultry-house.
From Driven Back to Eden by Roe, Edward Payson