cement deck footings

[mchoghead]

In haste I dug and poured footings for my deck 2 1/2' deep only to find out they should have been poured 4' deep to get under the frost line. The deck is already complete and now I am wondering the probability that these footings will heave and cause damage to the deck. It is attatched to the house. It would be a major undertaking to pour new footings at this point but if I need to take it apart to pour new footings I will. Any views on this are much appreciated. Thanks

[marson]

Whether or not your deck footings heave depends on the soil type (clay soils are more prone to heaving than sandy soils) and the amount of water in the soil--poorly drained sites are more prone to heaving than well drained sites.

Another option instead of digging new footings is to bury foam around the footing to limit frost penetration. Of course, this might be as much work as replacing the footing depending on how much room you have under your deck.

I'd just keep an eye on it this winter--if it heaves, then you know what you got to do.

[RickH]

It depends on the soil drainage and also the winter. I had a gate pole heave 3 inches in the 4th year after it was installed (last winter was brutal), before that it was fine.

[aemeijers]

Agreed. Unless you have to satisfy a building or bank inspector, no point in messing with it until there is a problem. Unless the ground under the deck picks up a lot of water, you may be fine. This probably would be a 'known defect' you have to disclose at sale time, however. Does your area require permits and inspections for decks? Some buyers and banks freak at 'unofficial' home improvements. (Thankfully, the township I am in is not that civilized. )

aem sends...