Sunday, 29 April 2012

A Sinking Feeling

Dear Joe,

I have a small porch on the side of my house that was build some time ago.  I has a quite significant lean to it that seems to be getting worse, not quickly, but gradually sinking along the outside.  I would like to know if there is a way to fix this or if I need to replace the porch.

Thank you for your help.  I love reading your piece each week,

Regards, Bill.


Thank you so much for the great question.  And thank you for being a loyal follower of my little piece.

There could be a couple of reasons for the sinking feeling you are having about your deck.  The root of the problem will be under; either under the deck or underground.    If the deck is truly sinking, then the footings on which it was build will be sinking into the earth.  Now unless you have tons of weight constantly on your deck, which I am sure you don’t, this is probably not the case.  Brand new footings may sink a bit over the first few years as the soil beneath them re-compacts after excavation, which is why it is eminently important when excavating for any concrete work, post, piers, floors or foundations, that the soil at the bottom of the excavation remains undisturbed, and all loose fill be cleaned from the bottom of the hole before aggregate or concrete is poured.  So if your deck is older this won’t be the case as the settling process is long since completed.

I think the better bet is that the posts which rest upon the footings have begun to rot.  If the footings are very close to the earth, and were of untreated lumber, then chances are water has wicked up through the end grain of the post and it has been gradually deteriorating and sinking, year after year.

To fix this you have a couple of options.  Both will require jacking up and levelling of the deck.  One will have you unbolt and replace the existing posts and resting them back on the piers.  If you can’t remove the posts because of the decks construction, then you should cut off the bottom foot of the post (or until you find solid wood) and replace this with a pressure treated piece of the required length to repair the damaged post.  Pressure treated or metal splints on all four sides will ensure that the repair will be strong enough to support the deck and its occupants.  A couple hours after work should be enough to knock off this little repair and have your deck sitting pretty for years to come.

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