Depends on your location. Some places will allow you to get an engineer and come up with a plan to bring it to code. Others will make you tear it down. I would call the permit office and find out if there was a permit pulled for the addition

If you can get a good price on the house, buy it...and then tear off that barnacle that was stuck on the back. Although the inside of that addition looks surprisingly decent, I would question the quality of the construction by anyone who would proceed to build something like that without a foundation. Who knows what is hidden in the walls, how adequate the framing is, how the structure was connected to the house, and what was done for electrical and insulation? It also looks like the posts supporting everything are out of plumb. It's not only not to code, but could lean and/or settle substantially. And it could collapse, especially if you are in earthquake country, or anywhere there are windstorms, tornadoes or hurricanes. If it ever comes to the attention of local authorities, it will be condemned, and for good reason.

What I can see of the rest of the house looks nice, so base your buying decision on the value to you of the original structure. If you buy it, plan on tearing down the back end -- which shouldn't be difficult -- and then restore the integrity of the original structure, or do an addition that meets code and shares something architecturally with the lines of the original.

Your instincts are correct about this, but it shouldn't be a reason to not buy it if you are prepared to deal with this problem. Good luck.

I would pass - it looks absolutely ugly - no way to redeem that. I question the piers holding it up.

Interior looks surprisingly nice. I'd have an inspector come out and check it out obviously.

Total side note non-sequitur... Erin, forget California, the largest fault in the United States is called the New Madrid Fault and runs from basically Chicago to New Orleans. It slips regularly, but the last time it slipped and caused a massive quake it was large enough to ring church bells in Boston and made the Mississippi flow backwards for several hours. Whole towns were swallowed by the river and ceased to exist. Anyway, interesting historical fact....

kudzu is right, if you are going to buy a foreclosure you have to be prepared to do significant work. In my area the bank usually asks far more than the property is worth based on its current condition. In other words, they price it high looking for someone that won't notice that it needs the back torn off because it wasn't permitted and isn't safe. How can it be safe without a foundation? I showed a foreclosure yesterday to one of my buyers and it needs absolutely everything: mold remediation, roof, HVAC, kitchen, baths, flooring, etc. The banks price is way too high for the amount of work. This is typical of many F/C'ed properties. If you are interested, do your due diligence and don't pay too much.

Remember the liability for non-permitted work rides with the property. Not with the person that did the non-permitted work. That means it is up to you to cure it at your expense once you own it. Be careful here. I would rip that thing down in a heartbeat.

PS As a Realtor, I see all kinds of violations and the bank sells AS IS and states that they have no idea. I was at the building department checking permits a couple of years ago on a property and the building department personnel told me about someone that had purchased a f/c in the same neighborhood, closed and then the next day the property was condemned so the buyer couldn't even move into the property. Don't rely on anything the bank may or may not tell you. Do your own research.

I’d say tear it off. It appears that there isn’t a way to make it look like it belongs there, given what little we can see of the original structure.

Barnacle is a good word for it. Plus, tearing it off would cure the no-permit issue.