Re: Sagging porch
Unfortunately it's impossible to tell over the internet what are the causes.... sight unseen.
Many things could be source of the issue and need to be determined before any proper solution can be recommended.
First thing to consider is there a proper base or foundation to support this structure for your region and soil conditions. If the foundation wasn't properly done then this structure was destined to to move .
There may also be an issue with water drainage that's undermining the foundation. Things like down spouts draining close by and should be extended past the structure or sloping the grade away.
Is there an issue with rotted wood structure that needs to be replaced?
Or a combination of all of the above.
While some of the suggestions you received like ..... concrete blocks with jacks .... have some merit .... but .... these may only be temporary if the conditions are incorrect and not properly addressed.
It's recommended to have someone properly evaluate the cause and suggest options as to remedy the problems.
Otherwise you may end up wasting time and money only to have a hodge podge of concrete blocks , jacks , posts and still have a sagging porch.
Hope this helps.
"" an ounce of perception -- a pound of obscure "