How to Repair a Sunken Deck

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How to Repair a Sunken Deck

For the lovers of peace and tranquility, a porch or deck can be an alternative heaven. Away from the humdrum of mundane life, you can get your dose of mental peace and indulge in some constructive thinking. These heavens of our present life are susceptible to damage with the passage of time. They can be fixed with some hard work and patience. If your deck is built on a downhill surface, it is possible that the posts installed to carry the mass of the deck have begun to sink. Sinking will take place if they have not been given a strong foundation by deeply embedding them in the earth. On top of that, if you are staying in a cold climate, then the problem of freezing as well as thawing would start pushing the posts deeper. The entire deck will sink as the posts sink.

There is an array of remedies to overcome this seemingly tough task. Ideally, there is no need to remove floorboards for performing repairs. However, in case if you see no clearance beneath the deck to work, in such case you might have to take some apart to gain access to the affected post in the floor.

You can put a jack or something similar below the joint which is near to the bad post. The deck should be slowly raised to bring it to the level again. You should not do it too quickly as doing it hurriedly can let the wood to pull apart the hangers. You must pause at short intervals to listen to any unusual sound. If something gets pulled apart, there will be noise.

Once the deck is back to its level, a lengthy pipe should be lowered. Make sure that the dirt must be made loose near the post out of the recently lifted area. Now it should be pushed down until resistance is encountered. The pipe should now be used like a funnel and gradually pea gravel should be poured in the hole. The pipe should be worked slowly up and down to make sure maximum amount of gravel is put into the hole. This process should be repeated till the deck comes at the right level, even after the removal of the jack. The following tips must be followed for improving the longevity of the deck:

  • Always check your deck for loose nails, railings and boards. Remove or replace nails that have stuck with screws. Care must be taken to immediately replace any loose railings so as to avoid any hazards.
  • Always clean dirt from the wood deck. For cleaning purposes, use any mild detergent diluted in water. In addition, proper time must be given to rinse it thoroughly.
  • Mineral spirits must be used to clear stains made by tree sap.



  1. rohini said,

    on March 27th, 2012 at 4:16 pm

    How do you lift a deck if it is like 5 or 6 ft above the ground.

    our deck has two outer corners one of which is sinking. i noticed two lumber pieces (maybe 4 or 5 ft in length) one below the other connecting the post to other two posts; the top lumber piece is at ground level; if you dig in, you would notice the other one, but i didn’t check yet to see how they are connected to the post; i was afraid that if i start to dig , the post may go in further.

    i have a 2 ton car jack (the one with 4 wheels), but i don’t know how to use it to lift up the deck, if the joists are so high.

    any advise would be helpful. thanks.