Most residential structures need roofs to be complete. Roofs provide shade and insulation. They keep the rain out.
Roofs need occasional repair and replacement. See links under "external links" for calculators to estimate the cost of replacing a roof.
Phrases using "roof":
- raise the roof - to make a lot of noise
- a roof over your head - being able to live in a home
- HowStuffWorks? on "How House Construction Works: Roof"
- HowStuffWorks? on "How to Repair a Leaky Roof"