Many composite decking manufacturers, including the popular Trex brand, offer warranties that protect against warping under specific conditions. These warranties typically last between 20 and 50 years, but they usually exclude claims related to improper installation of the product. Some manufacturer warranties only cover decks built by certified professionals.

Yes, but ensuring the deck has a solid foundation with adequate footings is critical before building, as the weight of a sunroom will put significant pressure on the structure below. Even if your deck is properly constructed, it may not be able to handle the extra weight. While some basic, lightweight, prefabricated sunrooms can sit on a deck with a strong existing foundation without additional supports, in many cases, the foundation and joists will need reinforcement. It is always best to have a structural engineer perform an inspection to evaluate the deck's quality and structural integrity. A professional can help you decide if reinforcement is sufficient or if it's better to tear down the deck and start over.

Expect to spend around $10,000 to $11,000 to replace a 20-by-20-foot deck. Using high-end materials like composite or exotic hardwoods can drive up the cost, as can custom features and design elements. You can also expect to pay more than average if your deck replacement requires a site evaluation or if you need the work done during the busy season.

Pressure-treated lumber is one of the most affordable types of decking upfront. This material is widely available, so you can usually find pressure-treated lumber at almost any local home improvement store you visit. Keep in mind that wood requires a lot of upkeep with repainting and restaining, so any kind of wood may be more expensive in the long run than something like PVC decking.