uri jip apeseodo gongsaga sijakdwaeseo najeneun so-eumi simhae.

앞에서도 = 앞에서 (in front of) + 도 (also/even/too).
So it implies “in front of my house, too,” i.e., in addition to some other place where construction is happening (mentioned earlier or understood from context).

• 집 앞에서 = “in front of the house” (location of an action)
• 도 adds the idea of “also/even” to that location.

공사 means construction work (roadwork, building work, renovation work, etc.). It’s a general, common term.
Related words you might see:

• 건설: “construction” in a more formal/industry sense (often about building/large projects)
• 공사하다: “to do construction work” (less common than using 공사를 하다)

Both are possible, but they emphasize different things:

• 공사가 시작되다 = “the construction starts/begins” (construction is the subject; it “gets started,” often felt as a natural/passive happening)
• 공사를 시작하다 = “(someone) starts the construction” (more active; implies an agent)

In everyday descriptions like this, 공사가 시작되다 is very common.

시작돼서 comes from 시작되다 (to begin / to be started).
Conjugation:

• 시작되다 → 시작되어서 → (contracted) 시작돼서

That 돼 is a common contraction of 되어 in speech and writing.

Here -아/어서 links two clauses and can mean because/so, or simply show a natural connection.
In this sentence it’s most naturally cause → result:

• 공사가 시작돼서 = “Since/because construction started,”
• 낮에는 소음이 심해 = “during the day the noise is bad.”

Context can also make it feel like “and then,” but the cause-result reading is strongest here.

낮에는 = 낮 (daytime) + 에는 (topic/contrast marker attached to a time phrase).
It means “as for during the daytime / in the daytime (at least)”, often implying contrast (stated or implied), such as:

• 낮에는 noisy (and maybe 밤에는 less noisy / different)

So -는 here is the topic marker 은/는 attached after 에.

이/가 often marks the thing being described as the subject of a state:

• 소음이 심해 = “The noise is severe/bad.”

You can say 소음은 심해, but it tends to sound more contrastive: “As for the noise, it’s bad (but something else might not be).” In a neutral description, 이/가 is typical.

심해 is the informal present form of 심하다 = “to be severe/serious/bad.”
So 소음이 심해 literally means “the noise is severe.”
Politer endings:

• 심해요 (polite)
• 심합니다 (formal)

Yes, it’s basically present: “Construction has started (so) it’s noisy during the day.”
Korean often uses the present to describe a current situation that began recently. If you want to explicitly mark the start as completed, you could use:

• 공사가 시작돼서 (already implies it started)
• 공사가 시작됐어/시작됐어요 (more explicitly “it started”)

Common polite versions:

• 우리 집 앞에서도 공사가 시작돼서 낮에는 소음이 심해요. (polite, everyday)
• 우리 집 앞에서도 공사가 시작돼서 낮에는 소음이 심합니다. (formal)

Everything else can stay the same; you mainly change the final ending.