Outsourcing is a subcontract, and is permissible where you partake in some of what is required in order to complete the task. It may be as little as simply buying the materials for the task required to do, for example, in the case of a painting job where you outsource that job to another person at a lower price, and compensate yourself for the task you have completed.
S.M. Leghaei and S.L. Al-Hakim