I've been at my construction employer for a while and feel I'm being taken advantage of as far as salary. How do I ask for a raise?

Ask for a meeting with your boss, or during your review ask to have a meeting regarding your salary, and have a list of all the things you've done to help the construction employer grow. Do your research on the industry salary average for your area, and let your manager know what you feel would be a fair salary. Most employers will do what they can to keep on productive (and happy) employees.