Learn Finnish: Onko kylpyhuoneessanne remontti? - Is there a renovation in your bathroom?

In Finnish, when a noun has both a case ending (like the "in" ending -ssa/-ssä) and a possessive suffix (like the "your" ending -nne), the case ending always comes first. So kylpyhuoneessanne is built like this: kylpyhuonee- (the stem for "bathroom") + -ssa (in) + -nne (your plural/formal).

Where is the word for "your" (teidän) in this sentence?

It is expressed entirely by the suffix! For first and second-person owners (my, our, your), Finnish allows you to drop the separate pronoun (minun, meidän, sinun, teidän) and just use the possessive suffix on the noun. You could say Onko teidän kylpyhuoneessanne remontti?, but dropping teidän is very common and perfectly natural.

Does -nne mean "your" for one person or multiple people?

The suffix -nne corresponds to the pronoun te (you plural or formal). This means it usually refers to multiple people ("y'all's bathroom"), but it can also be used as a polite, formal way to address one person. If you were talking informally to one friend, you would use the singular suffix -si: kylpyhuoneessasi.

Why is the location (kylpyhuoneessanne) in the middle of the question instead of the beginning?