Construction defect attorney here. New home construction defects are governed by a complex web of state statutes, warranty obligations, and common law theories. The first thing to determine is whether your state has a Right to Repair Act (like California SB 800, codified at Civil Code Sections 895-945.5) that establishes pre-litigation procedures you must follow before filing suit.
In California, the SB 800 process requires you to give the builder written notice of the defects and allow them an opportunity to inspect and offer repairs before you can file a lawsuit. The builder has 14 days to acknowledge receipt, then 14 days to inspect, then 30 days to offer a repair. If you skip this process, your lawsuit can be stayed or dismissed. Other states like Texas (RCLA, Chapter 27 of the Texas Property Code) and Florida (Chapter 558) have similar requirements.
Common construction defects in new homes include: improper grading and drainage (leading to water intrusion), defective roofing, foundation settlement, HVAC issues, plumbing defects, and window or door installation errors. Document everything with dated photographs and videos, and keep a log of when you first noticed each issue. The date of discovery is critical for statute of limitations purposes.
Regarding the implied warranty of habitability: in most states, new home builders provide an implied warranty that the home is suitable for habitation and built in a workmanlike manner. This warranty exists even if it is not written in your purchase agreement. The duration varies by state -- in California, structural defects have a 10-year warranty period under Civil Code Section 896, while other defects have shorter periods (1-4 years depending on the type of defect).
My strongest recommendation: hire an independent licensed inspector or structural engineer before the builder warranty period expires. Their report will serve as critical evidence if you need to pursue a claim later. The cost of an inspection (typically 500-1,500 dollars) is insignificant compared to the cost of repairing major defects out of pocket.