I'm having some trouble with the following sentence:
What's the meaning of the double "一部屋"? I think it's supposed to be each/every room, but I'm not sure. Also, is it read as "ひとへやひとへや"?
一部屋一部屋 is read as ひとへやひとへや, and means "each one of the rooms". Here 部屋 is used as the counter for rooms (一部屋【ひとへや】, 二部屋【ふたへや】, 三部屋【さんへや】/三部屋【みへや】, ...).
Generally, yes, this is a pattern that means "each ～" or "every ～".
In this project, each one of us is important.
Every word of his annoys me.
Let's take a look at them one by one.
She doesn't understand it unless I explain every time.