How to use "elapsed days"?

Good morning everyone,
my name is Eros and I am an architect, committed to building private residential buildings.
I apologize if the topic has already been covered, I tried to search the threads without success.
Please excuse the translation: I wrote in Italian and translated with Google Translate.

I am creating a work schedule with Ganttproject, and I have a problem:

  1. I created the calendar with working days and holidays,
  2. I created the activities with the various types of end-to-start links, etc.
  3. I have assigned the necessary working days to the activities
    … and here is my problem that I can’t solve:

How do I attribute the solar days (“elapsed days” in MS Project) to the curing time of the concrete?

  • It is an activity that takes place 7/7 days and 24 / 24h, it is independent from the working days calendar, but it is important for the subsequent phases.
  • If we do a concrete work BEFORE the holidays, which takes 28 solar days (elapsed days) to mature, I would like it to be clear in the activity to write 28 days, and not accounting tricks to make the system work, this to connect correctly subsequent activities.
  • If for some reason, the work will be done AFTER the holidays, and I forget to correct the accounting trick, the work schedule is no longer functional.
  • I don’t want to create activities with unreal working days,
    as I do not want to manually change the start-end dates of the activity (if the construction site moves over time, I lose the usefulness of the automatic Gantt chart).

Thank you for your suggestions.
Eros

Could you refine the question, please? What is the problem?
Using holidays for elapsed days, or using the lag in task dependencies?

Hello,
my problem is to use the holidays (and the weekend) for the elapsed days, only for some tasks.

Hello Baru! AFAIK, GP does not support resource calendars. Even less, for specific tasks.

MS Project does support it, if it helps to know it.