Decking Foundations

What Is Decking Foundation?

A deck foundation is not the same as a house foundation. Decking foundation carries the load concentrated at specific points on the ground, instead of being spread around the whole perimeter. The weight of a deck is significantly lower than of a house, since it normally uses timber decking; still, the point loading means the proper foundation is necessary. 

Importance of Decking Foundation

Decking foundation is crucial for durable, safe decking. No soil type, apart from solid rock, can hold a point load for long without support. That’s the role of footings—weight-bearing supports arranged at their base to help spread point loads over a large area. Their depth depends on the conditions; footings can stand very close to the surface or get below frost level. 

Deck foundation consists of footings, posts, joists, and bearers. The project starts by digging into the ground, and then concrete is poured into the hole. Next, posts are installed to create a firm basis on which the deck will be built.

Bearers are large, thick sections of timber or steel. Connected to posts, they create a solid, immovable structure. Finally, joists are fitted connecting the bearers at smaller spans, and that’s the frame for a sturdy, long-lasting, and reliable deck. 

Types of Decking Foundation 

The most apparent type of freestanding deck is the one in the middle of the patio, detached from all objects. However, many decks seem to be attached to the house, even when they are not. A freestanding deck is, above all, self-supporting. While it can lean to a house, it doesn’t use it for support. 

A floating deck lies on a gravel bed or concrete blocks. It is an ideal type of low deck foundation for a small, shallow, simple, flat deck that is not anchored to the house or the ground. Floating decks are typically up to two feet high above the ground; hence they don’t require railings to be considered safe. Building a floating deck comprises preparing the ground, laying a subframe, and attaching deck boards.

Decking Foundation Accessories

Ground screws, deck screws, or post screws are the same type of simple and effective foundation. Deck screws work the same way as a concrete post or pier block, allowing for quick and easy construction of stable foundations. Ground screws are commonly made of galvanized steel, resistant to corrosion. They are also reusable and suitable for all terrains and surfaces.

Deck pedestal system allows for the construction of elevated decks built over uneven surfaces, such as pipes, drains, or slopes. The self-levelling decking pedestals eliminate the need for costly level-up framing. The PVC pipe allows the system to have a variety of heights of over 35 inches and up. Floating decking systems require proper alignment of the pavers for water drainage.

Things to Consider About Decking Foundation

Both freestanding and floating decks have their pros and cons, as well as expenses. 

Opting for a freestanding decking foundation will spare the house structure from the added loads. Attaching the deck to the house requires an adequate connection between the deck and existing structures. That means locating the rim joist, stripping the adjacent exterior finish, and attaching a ledger board. The ledger must be covered with corrosion-resistant flashing to prevent water from reaching the rim joist.