Hi Eman,

It has been a while since your post, but if you are still looking for a Job Costing Solution for Odoo, we have created this now for Odoo.
https://odoo.interacct.com.au/job-costing-by-interacct/

You will be able to create unlimited Sub Jobs under Parent Jobs which will allow you to breakdown your Jobs to whatever level of detail you like. Under each job you can record the multiple Estimates which can convert to Budget, and then you can track your actuals against this budget with Costs seperated by Materials, Direct Labour, SubContractors, Machines and Sundry Costs.

Let me know if it is what you are after. 

Hi 

You can use budgeting from accounting and like that budget with analytic account of the project ( this is stanrtard on odoo )

in case you need to customize a contracting module their is 3rd party apps can help