Decks can sink, crack, break apart, and collapse all because of deck foundation problems. To repair a deck, you need to build temporary support posts, or you may need a hydraulic jack. It sounds like a lot of work, but many of these problems are avoidable. The main strategy in dealing with the problems is to act proactively. Prepare the ground for the foundation you will install. Understand that there are two major foundation problems, and they are foundation washout and sinking posts.
Foundation washout occurs because of runoff. It primarily occurs on steep hills. However, any grade is susceptible to some runoff. Before you build a deck, you may want to look at the soil quality around your house because sandy and silty soils are more susceptible to erosion and runoff. The best defense against runoff is a living barrier. Trees, shrubs, and bushes all provide root systems that help to hold soil in place and absorb water. If the area around your deck is too dark for many plants to grow, gutters to allow better drainage, or even rebar to hold deck posts in place, may be necessary. If the soil is too unstable and runoff is a major problem, consider consulting a professional to have custom footings installed.
Unsettled soil can cause a deck foundation to sink. A newly built house will leave the soil around its foundation loose from digging. If your house is new or you did work on the foundation, consider waiting before constructing a deck. Unsettled soil is a cause of driveway and sidewalk cracks. Likewise, it can damage the foundations of decks, and, in severe cases, cause the foundation to sink. This is a problem that is best handled proactively. Compact the soil before you build your foundation, and if you are unsure about the soil, consult a builder before building the deck.
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Damage caused to Deck foundation:
Deck Foundation issues can cause serious damage to a deck by causing the deck to sink and become slanted. The slant caused by a weak foundation can crack wood, cause the deck to fall in on itself, and the slant can even damage the walls of the house to which its attached. Its best to correct these problems as soon as they are noticed, for a deck with a sinking foundation not only does not look as good as it could, but it is also unsafe. Make sure to get a deck safety inspection done every year.