Deck Footings & Structural Timber

Outdoor structures should be supported by basic foundations which are called footings. Footings are an essential part of building an outdoor structure and help to eliminate settling and slippage. Footings can also help protect wooden posts and beams from direct contact with the earth, minimizing the possibility of rot and insect damage, therefore extending the life of your outdoor project. Posts and beams that do come into contact with the earth have a tendency to rot more quickly, eventually weakening the structure.

Outdoor structures, such as decks, porches, some garden sheds, and gazebos which at some point will hold weight, require strong footings as a base to build on. If the structure is lacking a strong and stable set of foundations, the wooden posts and beams used to create the structure may fail - resulting in possible injury to the and destruction of the structure.

Footings can also help to prevent frost heave. Frost heave is the term used to describe what happens when wet or damp soil freezes. Frost heave will cause the structure to 'heave' upwards causing the soil around the structure to push up. The movement of the soil can push up on the posts and the structure attached to it. When movement of more than 1 inch occurs, there is often structural damage to decks, porches, garden sheds, and gazebos. If the structure is attached to your home, damage may occur to your home. In order to combat this problem, footings should be placed 6 inches or more below the frost line. The frost line is the maximum depth where the ground will freeze in the winter.

In choosing a footing type, consider the following:

- Foundations should be large and stable enough to provide a solid resting place for your posts and/or beams.

- Foundations should be placed below the frost line, usually a minimum of6 inches, this is to prevent frost heaving from occurring.

- Foundations should rise at least 3 inches above ground level to keep the post dry.

- Reinforcing bar (re-bar) should be placed in the concrete to add strength to the footing, if necessary.

- Gravel or crushed rock should be compacted around the post to allow water to drain away from the footing, especially if drainage is poor.