Per City of Sachse Code of Ordinances - Chapter 3, Building Regulations, Section 3-5. Permit fees required under construction codes:

A person commits an offense if he or she builds, repairs or constructs any building or structure in the city without first obtaining a building permit for such.  An applicant for a permit shall prepare and file an application, on a form to be provided by the building official.  Upon proper completion of the building permit application and payment of the required fees, which said permit fees shall be established by resolution of the city council, the building official shall issue a permit.

Permits are required for the following:

1.  All structures over 18 inches (18") in height
2.  Accessory buildings over 120 square feet
3.  Fences
4.  Decks
5.  Concrete
6.  Carports
7.  Swimming pools
8.  Add-ons
9.  Sewer lines
10. Electrical
11. Plumbing
12. Sprinkler systems
13. Signs
14. Foundation repair (if piers or footings are added)
15. Roofing (if deck is being replaced)
16. Stock tanks