What to do when the deck footer is sinking?
The short answer is I don't know.
We don't have X-ray vision. Although some people expect home inspectors to have it.
Deck footers, what the posts or columns rest on, can be over or underground.
There are many kinds, and can be adapted to local needs.
Why local needs?
Because the IRC (International Residential Code) defines footer requirements, where you live matters.
Without getting too technical, footers need to be made of materials that don't decay, like concrete, and be "Below Frost Line."
That depth varies. Around here the counties want to see footers 24" deep.
Why? Because freezing and thawing can cause things to "heave," or move up or down, altering the integrity of the deck support.
Just looking at this deck one can see that the supports on one side are sinking.
What does it mean?
Not having X-ray vision I can't tell exactly, but the footer may not be present, it may have decayed or cracked, it may not be deep enough, or something else?
Did this deck builder have a permit? Was the hole deep enough? Was the footer present when the county inspected it?
So many questions!
An engineer friend of mine says that once things begin to move they continue to move unless something stops that movement.
But, as to my job, I observe and report. What happens after I note something is what happens after. The house is the house.
My recommendation: it doesn't take a professional to see such dramatic evidence like this! It might be wise to ask for a copy of the permit at the time of an offer, or ask as a part of the offer to have that problem professionally examined and repaired. The home inspector will take you there anyway!
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560