Is the C in Colonial capitalized when talking about a style of building?

Yes, the "C" in "Colonial" is capitalized when talking about a style of building.

This is because "Colonial" in this context refers to a specific architectural style, and proper nouns are capitalized in English.

For example:

* "The house is a beautiful example of Colonial architecture."

* "We visited a museum with a collection of Colonial furniture."

However, if you are referring to the historical period of colonization, you would not capitalize "colonial."

For example:

* "The colonial period in America was marked by significant political and social change."