Get matched with top deck cleaning pros in Johnson Creek, WI

Composite decking requires a solid foundation or substructure for support. This base is typically a frame composed of posts, beams, joists, and footings. The frame can be built from various materials, such as composite, plastic, timber, or metal, depending on your budget, deck type, and environmental conditions. For maximum stability, a professional deck builder may recommend installing this frame on top of a solid concrete base. It is best to discuss the most suitable substructure design and materials for your specific project with a professional.

Before installing a deck, you must build a base for the deck to rest upon, often made of compacted soil or gravel. While gravel is an optional material, it helps with drainage. Some contractors also recommend installing a weed control membrane, which helps provide a solid foundation for the frame. In the case of an elevated deck, a pro will often lay down a concrete slab as a foundation. 

Most building codes require that railing spindles (also known as balusters) on decks or stairs be spaced no more than four inches apart. This safety standard is often called the '4-inch sphere rule,' which means a sphere with a 4-inch diameter should not be able to pass through the opening between balusters. This rule is in place to prevent small children and pets from slipping through the railing. For the same reason, the space between the bottom rail and the deck or floor surface 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 essential to check your local building codes to ensure compliance before starting your project.

Deck skirting shouldn’t touch the ground, especially if you have a wood deck, which is vulnerable to moisture. Ideally, you should leave at least 3/4 of an inch of space between the deck skirting and the ground for more ventilation. Pros also recommend that you incorporate about 1 square foot of space for ventilation for the underside of the deck to every 150 square feet of decking. Proper ventilation prevents mold growth and rot that can damage your deck.