Does anyone have any experience with doing home renovations (ie, adding rooms, 2nd story, expanding building footprint) after having foundation work done?

We are looking at a house that would be a fixer-upper, but it has had foundation work done. Here's what the listing says:

• 29 foundation piers on the perimeter in 2001
• 11 foundation piers internal in 2007
• 4 foundation piers internal in 2016

It's a 2200 sqft single story home in North Texas (read black clay soil) built in 1980.

Obviously we would work with an engineer to get a formal recommendation and determine what load the foundation could handle. I'm just trying to figure out if the existing foundation work would be a "hard pass" on any future renovation work or not.

Seems like the real problem with the foundation may have never been solved

Wouldn't buy any house with piers on the interior. Exterior piers are pretty common since house pads are usually built up so rain flows away from the house, and improper drainage among other things can allow the edges to sag. Piers on the interior means the soil wasn't prepared correctly or water is washing something out and will probably continue to have issues until the entire slab is fully supported by piers. Unless the budget still makes sense after planning for another few interior piers every 5-10 years, I'd look for something else.

I'd hard pass on that house, that's a ton of piers for that sf. Screams potential money pit for future plumbing, more foundation, drywall/cosmetic, window/doors sticking.

Don't just walk away...RUN AWAY!!!

Run away