If you want an answer that is meaningful, why don't you consult your local code construction official...or a licensed professional Engineer who specializes in structural design?

I'm honestly flabbergasted that anyone would endeavor such a project, which if not done properly could result in collapse, possible serious injury..or worst case scenario, even death...but none the less rely upon some anonymous internet advice for structural issues.

(Shaking head).

I certainly second your suggestions, logic, but Jeez, lighten up. The man is just asking for opinions, looking for options, trying to educate himself. That's what this site is all about. The tone of your response is, frankly, condescending and insulting. Building atop the old stone foundation may or may not be a sound choice for long-term stability, but the idea that a catastrophic, fatal collapse (of a porch, yet) might result is being melodramatic in the extreme.

My first question is why is this stone and mortar foundation there in the first place. If it is 3 ft wide and runs parallel to your house, is it a continuous spread footing for your house foundation wall?

Do you have a basement with the stone next to the wall, or is this footing continuous under the structure?

If it is not supporting anything, I don't see why you couldn't put your sonotube and porch on it. However, If you plan to use your new "footing" for a substantial addition you'd be best off getting confirmation from a local engineer that what your building is adequate for your long range plans.

good luck.

airqualguy: "..The man is just asking for opinions, looking for options, trying to educate himself. That's what this site is all about..."

Hardly. An internet message board is not the place for "education", as the term education implies that the information received is equivocally meaningful which is ESPECIALLY important regarding structural issues.

In addition, you are assuming that the project has been described properly...however, those who lack knowledge in structural issues often also lack the ability to correctly assess the situationÂtherefore making any opinions on how to proceed with said project virtually worthless.

That said, you are entitled to your opinionÂjust as I am entitled to mineÂ..and my opinion remains that erring on the side of caution by obtaining a quantifiable educated assesement regarding structural issues is the responsible thing to doÂ.and, "the melodrama" as you call it, is far more beneficial than offering an opinion based on info that may or may not be accurate.
If you find that to be condescending and insulting, so be it.

"those who lack knowledge in structural issues often also lack the ability to correctly assess the situationÂtherefore making any opinions on how to proceed with said project virtually worthless."

Or electrical? Or plumbing? HVAC? Remodeling? With that attitude, one has to conclude that this whole web site is worthless.

logic:
If you read my post, I essentially agree with you but air_qual has a point that you're wording and admonition is rather "melodramatic". e.g. "(shaking head)"

The OP describes his plan to use 22 in. square pads with 10 in. sonotubes buried 42 in. below grade to support his new first floor porch. Sounds quite reasonable to me and implies he has a fair understanding of his undertaking. All he is doing is soliciting an opinion.

You don't need to be a PE or stamped plans to design/build a porch. Any good contractor could answer it and there are some of those who post on this site.

airqualguy:
"..Or electrical? Or plumbing? HVAC? Remodeling? With that attitude, one has to conclude that this whole web site is worthless."

In terms of obtaining reliable meaningful "advice" for issues related to those you've itemized, yes it is....as a bright 10 year old can respond, claiming to be an electrician, etc. a P.E., etc, and no one would be the wiser.
As the heading on the forum states, "This is the place to discuss the ins and outs of home repair."....note the operative word "discuss"; its a discussion forum...period..no more, no less....its not meant to replace the expertise of verified licensed professionals.

sdello: "You don't need to be a PE or stamped plans to design/build a porch. Any good contractor could answer it and there are some of those who post on this site. "

Quite true. However, exactly how does one determine that the person who responds is "good"...or even a contractor for that matter,simply from a response from internet forum? They can't.

In addition, in many, many places, one does need to file plans...apply for permits...and have the work inspected by the local code official..which goes much further in assuring that the plan is correct, then an anonymous internet opinion. In NYC for example, one can't design a porch LEGALLY unless they are a licensed Architect....and, one must be a licensed Architect to even file the plan for the permiits.

Last but not least, not to burst your collective bubbles, I'd rather be thought of as melodramatic than irresponsible.

To each his (or her) own.

"As the heading on the forum states, "This is the place to discuss the ins and outs of home repair."....note the operative word "discuss"; its a discussion forum...period..no more, no less....its not meant to replace the expertise of verified licensed professionals."

I believe that is all anyone is doing. he asks an opinion...one is offered. It is his perogative to use that information however he wishes. It's prtetty obvious there are no warrantys or any legally binding contracts.

I could tell this guy to fix his foundation by taking a bath with a plugged in toaster. If he did is it my fault?

You're the only one that is screamng from a soap box. Have you ever watched This Old House or any home improvement shows. Constructing a porch or a deck is a pretty common subject. Codes are avaiable at the library. You question credentials of anyone that posts, have you ever investigated the credentials of the local building inspectors? how about home inspectors? and they are the "professionals".

If you're so skeptical about internet forum information/posts why do bother with them? to troll for these types of discussions?

sdello:"You're the only one that is screamng from a soap box"

My, my...now who's being melodramatic? ;-)

With regard to your question on building inspectorsÂ...... they have been investigated extensively in my state of NJ...and many were found to be incompetent and/or unethical. There are indeed both the good and the bad...and the in between.
As far as home inspectors are concerned...I consult to the profession on a national basis...and there are the good and bad and the in between in that profession as well.
This is a given.

That said, there are no guarantees on ANYTHING...but there is a HUGE difference between taking advice from a virtual unknown entity Â..such as a poster on an internet forumÂ..who, as I said before, could be a 10 year old...perhaps with nothing better to do between gaming but give unqualified advice...and an actual and a verifiable entity.

After all, if this was a forum for discussing finances, would it be prudent for a reader to take their life savings and invest it in a stock on the advice of another poster....since, after all, there are many crooked investment brokers...so, an anonymous internet poster is just as reliable?

If you believe so, I have a hot stock tip for you.....I know its hot because I read about investing in a book at the library. ;-)

All kidding aside, hopefully, this time around, you will get the point, because the fact that you even asked that question...and the fact that you apparently needed to resort to an ad hominem attack in an attempt to make a point, and the fact that you seem to think that anybody can equivocally understand and implement code from a book found in the library...which BTW, is more often than not outdatedÂ..only serves to prove my point even further....that internet advice from an unquantifiable entity is basically worthless.

Now, that said, you donÂt need to agreeÂnor do you even need to read what I may write. You are free to move onÂso enjoy.

Stock, anyone? ;-D

If this is your point

"that internet advice from an unquantifiable entity is basically worthless."

then, yes your last post demonstrates it quite well, thank you.

P.S. In case you're interested there are four forums at this site alone that discuss finances. Have fun.

Here is a link that might be useful: forum list

sdello: In case you're interested there are four forums at this site alone that discuss finances. Have fun

Now that's the spirit....have fun! Exactly my point.

These forums are great for discussion and enjoyment...nothing more...nothing less. Have a great day. :-)