Attach Support Posts to Existing Concrete Path

We have a problem with a sunroom that over hangs an old concrete path concrete, is about 50mm thick

when we tore off the fiberlight only to find the support posts where just 150x50 untreated rubbish, one each side not quite midway and one under the door which the deck and steps were

the room had dropped as the window was out and sliding door hard to move and lock
there was only one 120x120 H4 post near where it joined the house which was fine

So we replaced the two rubbish supporting posts in the middle with 120x120 H4 on concrete pads (reg) 300x300x100 and replaced the one under the door

now get this, there is no more support out beyond the mid section and over hangs the old foot path which looks quite solid
Now which is the right way to put in support posts and attach them the the path below? 1 in each corner and 1 in the middle
currently have end on support blocks

1 cut post 100mm short and concrete in a box frame
2 sit post on concrete and concrete an apron around it
3 punch whole in path and concrete to post so post is above the level of the path = very hard option
4 pour a boxed 100m high footing for post to sit on

problem dont want the concrete to far out past the edge of the posts into the path eg 50m would be ok
anyhelp would be good as there are a few of use that have dif ideas

Don't even think about sitting a pile on top of an old 50mm thick concrete path. You need to get a builder involved - I'm not quite sure what you're doing from your description, but it sounds like you're out of your depth.

option3 is a minimum, cut a section out, dig your post in and allow 100 of concrete below it, fill back to path level, post can finish at whatever height you want it to - be aware that concrete shrinks as it cures so you either need to lift the subfloor slightly and lower it once initially cured or pack the pile later - quite common when repiling without lifting
plus if it is part of an existing structure you may well need a sign off on the work, permits and inspections etc - although you shouldn't, you're replacing like with like?, or was it cantilevered and now you're supporting what was an unsupported wall

seems a strange way to biuld it originally, perhaps it had those supports there just sat on the path and over the years they've fallen out, leaving the whole thing just hanging

I'd be tempted to cut the path and fit new 140X140 h4 piles in a proper footed hole, then in a couple of months time jack it all level and pack to the new piles - check packings on all others once you jack it

thanks i thought so, looks like the concrete cutters can cut out the path
so we can get access to dig holes for the reg footing
yeah they way it has been done is pretty sad and who built it needs a fair kick + the place is 30yrs old and the sunroom added later over top of the old deck and steps

I had the same thought. Go through the path to solid ground underneath.