A sunroom will add more value to your home than a deck, but with a much higher up-front cost. Depending on its construction and function, a sunroom may be counted as additional living space, while a deck is strictly an outdoor feature. Both will increase your home’s value, but the sunroom will have a much bigger effect.

Composite decking requires a solid foundation, substructure, or subframe to ensure stability. This base is typically composed of posts, beams, joists, and footings. The frame's joists can be built from various materials like composite, plastic, timber, or metal, as long as the base can support the deck's weight without shifting. A professional deck builder might recommend installing the frame on a solid concrete base for added durability. The final design and materials for the substructure will depend on your budget, the type of deck, and environmental conditions.

While experienced DIYers may take on the challenge, hiring a licensed professional is often the best route, especially for larger or elevated structures. A local deck contractor is typically the best pro for the job, as they have specialized experience and are knowledgeable about local building codes, ensuring your deck is built safely and designed to last. Other professionals who can build a deck include general contractors and carpenters, who may be more readily available in some regions.

Materials for a second-story deck must be weather- and rot-resistant, though the specific choices will largely be determined by your budget and style preference. Pressure-treated wood is on the lower end of the price scale, but it can be customized and stained the way you like it. Composite, on the other hand, is pricier for installation and has fewer options for customization, but you’ll save money and time in the long run because it requires little maintenance.