If you are planning a project that requires the input from an engineer they should be consulted early in the project. Your first call should be to your city planning or permitting department to determine the type and scope of permitting you will need. If you are using a general contractor they will usually pull all of the necessary permits; but it is always good for the homeowner to be aware of what is required in the location where the building or renovation is taking place.
Many jurisdictions require the input of a qualified engineer as part of the original permit process. Towns and cities in most of the Texas Coastal counties require a WPI-1 form to be filed with the Texas Department of Insurance (TDI) prior to starting construction. The earlier an engineer is involved the better. Interview several engineers if possible, many will offer an initial consultation at no charge to define the scope of a project and set the expected fees. An engineer must be on the TDI list of approved engineers to submit the forms for windstorm certification. The TDI maintains an easily accessible list of approved engineers on their website.
General contractors frequently have engineers with whom they have worked before and have established a comfortable relationship. This is fine and can be a particularly good working relationship; but I recommend you establish early on which party is responsible for payment to the engineer. It is best if you know the name and contact information of the engineer so you can verify that they have been paid on time. I have seen more than once a situation where the project is complete and the engineer has not been paid and is reluctant to submit the final forms to TDI until they receive full payment. The homeowner has the choice whether to pay a second time for the engineering services, initiate a lawsuit against the contractor, or simply forget about obtaining windstorm insurance.
Establishing contact with an engineer who is working directly for you eliminates this problem and gives you, as the homeowner, a greater degree of control. In either case, the earlier you have an engineer involved in your project the less likely you will be to find yourself in the position of having to redo work that was done incorrectly.