Learn Romanian: Echipa va construi temelia clădirii. - The team will build the building's foundation.

Feminine nouns ending in -e in the singular almost always base their genitive and dative forms on their plural. The plural of clădire is clădiri. To make it definite genitive (of the building), you attach the definite article -i to the plural form, giving you clădirii.

We are saying "the foundation OF the building." Why isn't there a possessive article like a between temelia and clădirii?

You only need a possessive article (like a, al, ai, ale) if the two nouns are separated by another word, such as an adjective, or if the first noun is indefinite. Because the definite noun temelia sits immediately in front of the genitive noun clădirii, no extra word is needed.

Is there a difference between using temelia and fundația for a building's foundation?

They generally mean the same thing and are interchangeable in everyday speech. Temelie is an older word of Slavic origin that is also heavily used in metaphorical contexts (like the foundation of a society). Fundație is a French-origin neologism that sounds slightly more technical or architectural.

Can I use a plural verb here since echipa refers to a group of people, similar to how British English sometimes handles collective nouns?