The teachers are not allowed to use school mail for personal reasons also you will get them into trouble. As a retired teacher, I do not email them on school email, misuse can lead to the lost of their job. There are strick guidelines for them, it's tax payers funds.
A number of schools in my area of Ohio have e-mail addresses for the staff as well as teachers. You can Google the name of the school. If you don't find the school e-mail & teacher addresses, then call the school & ask for the teacher's email address. Just like the rest of the world, the teachers can be reached at various times of the day., Even if they are at home most probably check their e-mail. You can have a chat with a teacher by e-mail & if you feel you want to meet face-to-face, then ask for a day & time when you are both available.
Best of luck,
You can rely on teachers to be at school during the same approximate hours the childern are present for classes. The best way to be in touch with them is to call the school and leave a message. The call will most often be returned.
If the school or the teacher want you to have the email address they will offer it to you.