How should I obtain acknowledgement or extra pay for extra work?

If you are on a salary program it is expected that you will do what the job requires. If there is a season when the work load increases excessively, you may want to discuss this with your construction manager to see if there is any extra reward for the extra work. However you should be aware of what positions pay for the role that you are performing so that you do not ask for something that is not justified.