Depending on your locality, some domestic building work that cost above a certain price require a written contract, while smaller jobs require only a detailed written quote with a fixed price. Whatever the case, it is useful and much safer to have a written contract when partnering with a contractor or builder for building reconstruction.
Before signing the contract or the agreement, you should read it carefully. Many obligations arise from a written contract, and so it’s important that you have a full grasp of everything that the contract entails, lest you breach the contract for non-compliance, or the other party does so. If there are items in the contract that are not clear to you, seek out legal advice from a practicing lawyer. You should not sign a contract while there are still ambiguities in your mind.
Make sure that the contract includes the whole plan and complete details for all the reconstruction work to be done, and a definite starting and completion date. Check to see that the total cost is stated clearly and fixed. Both you and the contractor should sign the contract before the work begins, and both of you should have your own copies of such contract.