Pressure-treated wood contains preservatives that give the material internal protection from rot and pests. Untreated lumber won’t last more than a few years unless you choose a more expensive wood, like cedar, that naturally stands up well to moisture. Composite decking can outlast wood but is more expensive and doesn’t look as natural. Keep in mind that you’ll need to seal any exterior wood product to protect it from the elements and other forms of external damage.

Putting lattice under a deck will create a polished look that allows for air ventilation. You can also store items underneath as the lattice provides privacy and protection from the weather. You can also put lattice under a porch to create a polished look in the front of your house.

Although composite decking is extremely durable, it’s also susceptible to extreme heat. Prolonged exposure to sunlight can cause fading, warping, and cracking. Composite also retains heat more than wood, which makes it dangerous to walk on in the summer. You can help prevent heat damage by only building with composite in shaded areas or using rugs to cover the hottest spots.

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.