Learn Hardcore Russian: Новое здание будет построено к выходным. - The new building will be constructed by the weekend.

Будет построено is the future passive construction of the perfective verb построить (“to build”). In Russian passive you take the future tense of быть (here будет) and add the past passive participle (построено). This highlights the building as the recipient of the action, without naming who does the building.

Why is Новое здание in the nominative case?

In a passive sentence the thing being acted upon becomes the grammatical subject, so it takes the nominative. Here Новое здание (“the new building”) is the subject that will be built.

Why does the participle построено end with -о?

The ending -о shows neuter singular nominative agreement with здание, which is a neuter noun. Had the subject been feminine (e.g. новая школа), you’d see будет построена ending in -а.

What case is выходным after к, and why?

After the preposition к you always use the dative case. Выходным is the dative plural of выходные (“weekend days”), so к выходным literally means “toward the weekend days,” i.e. “by the weekend.”

What does к выходным mean exactly? How is it different from до выходных?

Both can translate as “by the weekend,” but:

до выходных stresses “before the weekend arrives.”
к выходным suggests reaching a deadline “around” or “by” the weekend. In everyday speech they often overlap, but к emphasizes the time target.

Why is the perfective verb построить used here, not the imperfective строить?

Perfective verbs in Russian denote completed actions. Since the sentence speaks of finishing the building by a certain time, построить (and its passive form) is correct. The imperfective строить would imply an ongoing process, not focused on completion.

Can I change the word order, for example, К выходным будет построено новое здание?

Yes. Russian has fairly free word order. Placing к выходным first shifts emphasis onto the deadline (“It’s by the weekend that the new building will be completed”). The default neutral order, however, is Новое здание будет построено к выходным.

Who performs the action in this sentence? Where is the agent?

This is an impersonal passive construction, so the agent (builders, company, etc.) is left unspecified. If you wanted to name them, you could say Новое здание будет построено строителями к выходным (“The new building will be built by the builders by the weekend”).

How is будет построено pronounced, and where is the stress?

Pronounce it as [boo-DYET pa-stro-YE-no]. The main stress falls on the second е in построено: по-стро́-ено.