Yes, transforming a deck into a sunroom is an absolute possibility. Building a sunroom involves framing in the deck area with walls, adding windows, and affixing a roof. This project is not an easy task, but it does provide a stylish addition to your house. Not all deck designs support this type of renovation project, so consult a professional deck builder before beginning.

Most building codes require that spindles or balusters on deck and stair railings be spaced no more than four inches apart. This safety standard, often called the '4-inch sphere rule,' is designed to prevent small children or pets from slipping through the railing. A good way to visualize this is that a 4-inch sphere should not be able to pass between two spindles. For the same safety reason, the space between the bottom rail and the deck floor should also be no more than four inches. As a general guideline, professionals often install three balusters per foot of railing. However, since specific requirements can vary by location, it is crucial to check your local building codes to ensure compliance before starting your project.

For a 12x20-foot (240-square-foot) deck, you can expect to pay between $7,200 and $14,400. This cost is based on a general price of $30 to $60 per square foot. The final price will depend on factors such as the decking material, design complexity, deck type, location, and local labor costs. Keep in mind that add-ons will increase the total; for example, adding an under-deck drainage system to a deck of this size could cost an additional $7,700.

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.