I can see the internal condition of the the studs from here, and it’s not good. You may not get 6 months.

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I would worry that something might collapse and cause injury to the tennants and their families. Big liability. Tennants, also have the right to know that there could be a potential problem.

Yes, get a structural engineer. It won't cost much and you'll get a definitive answer. From your description of the house, I think it's more than likely there's little or nothing to worry about.

I'm not sure I've ever seen a 150-200 year old house that didn't bulge here or there; uneven floors are a given. Unless there is evidence for sudden, recent movement, or unless it is extreme it's probably not a cause for concern. By all means have an engineer, or better, an old house specialist look at it.

There are exceptions, but most old houses were overbuilt by modern standards. The architects didn't have computer programs telling them how to design the cheapest possible structure that might still hold up the roof. They built with solid old growth lumber, not sawdust and splinters stuck together with glue.

That house is likely to outlast you. But if you want or need peace of mind, I guess you can get some -- for a price -- from a structural engineer.

DavidR:

You're perpetuating myth. Building codes were implemented because people were dying unnecessarily. Things like fire stopping blocking in between your old growth "real" 2x4s that prevented each stud bay from becoming a chimney.

Truss Joists International (TJI)s, "sawdust and splinters stuck together with glue", are stronger and stiffer than natural sawn lumber. This is math and math isn't up for debate. If you want your floor tile to not crack and want to have clear span in your basement, that's what you'll use. And they can make them out of bushes instead of what's left of our old-growth forests.

They don't build 'em like they used to and it's a damn good thing they don't.

Hey, I'm sure there are people out there who aren't bothered by the possibility of their home having such serious safety issues that they could be killed at any given moment, @Joseph, I just haven't met any of them.

Probably because they're already dead. :P

There's a reason why code requires TJI's to be covered with drywall now. "sawdust and splinters stuck together with glue" have the fire resistance of newspaper. If you are "lucky" your TJI's were treated. Or maybe not...

https://investigations.bergermontague.com/weyerhaeuser-recall-tji-joists-flak-jacket-lawsuit/

Fortunately, no one has ever died from when a " front outer facing wall is bulging outwards a little".

Firefighter safety threatened by floor joists

Some first responders refuse to enter burning new homes

https://www.cbc.ca/news/canada/windsor/firefighter-safety-threatened-by-floor-joists-1.1285808

Pre-engineered floor joists, made from wood chips and glue, burn twice as fast as traditional wooden joists and can suddenly collapse from beneath the first responders.

I'd love to be able to pop back in in a couple hundred years to see how all of our engineered wood products are holding up. Almost all of the plywood I run across from the 1920s-30s has delaminated from glue failure. I know it's supposed to be better now, but...

If I had to bet whether a new house or a 200 year old house today would still be standing 200 years from now my bet would be on the old house. (of course all the bad houses built 200 years ago may already have fallen down)

The condition you describe could have existed there for the last 50 years or more. It could last this way another 50 years or it could fail tomorrow with a good gust of wind... there is no way of telling... Like Sophie pointed out only the magic ball can tell the future or spring for a few $$ and get a licensed Engineer like others suggested to see what's going on and if the structure is safe or not.

Good luck

The US must not care about the safety of firefighters as much as Canada cares about theirs. And then there's Justin, I'd move to Canada and wind up with a restraining order for stalking him (possibly sneaking up to the windows in his house for a better look ;) he's rather handsome, plus...we've got the Orange Menace and nobody wants to stay around to see THAT.)...Anyone have a spare room in their house up in Canada that I can hide out in ??- for a reasonable rent of course - no guarantees that the RCMP won't eventually show up to drag me off and send me back to the US even though it would definitely count as cruel and unusual punishment. Lol

Some risks can be taken, some should not. If there's a way to get someone who knows what they're doing at a reasonable price just for peace of mind and possibly come up with a strategic plan to deal with any issues on an urgent-okay to wait-you don't have to worry for a long while basis? Go with the pro who knows what they're talking about and what they're doing, it's money that will be well spent.

Now we need to bring politics into this forum? If its so bad, go, get out, we won't notice!

Joseph, you are correct that modern construction materials are scientifically designed. Science is good. It's also essential, because the solid, old-growth lumber that went into houses a century ago is long gone, and it's never coming back.

For the last half-century, though, materials sciences has been used in construction not just to replace materials that we can't get, but also and primarily to make building houses as cheap as possible. As I said above, engineers use powerful computers to design in the absolute minimum strength required to hold up the structure, at the absolute minimum cost and absolute maximum profit for the builder.

Then there's the abominable quality of the traditional dimensional lumber they still use -- soft, weak, warped, cracked, sometimes undersized. I don't know how anyone can build a plumb wall with that junk.

I'm not saying that current construction is defective as such, just that older homes were often built stronger than they probably needed to be. Those old houses can't be replaced. We should treasure them and care for them. To me it's a crime when someone buys a solid old house, knocks it down, sends that good lumber to the landfill, and builds a new Tinkertoy McMansion on the land.

...Could be worse, they could be planning to make and sell a ton of barn doors with the lumber. ;)

"Pre-engineered floor joists, made from wood chips and glue, burn twice as fast as traditional wooden joists and can suddenly collapse from beneath the first responders."

Some local folks were complaining that a new traffic roundabout caused about 50 accidents a year where the former intersection only caused 2 or 3. The difference is now the 50 are just fender benders, the 2 or three were injury or fatalities. Kinda the same thing here. Yes, engineered lumber may be more flammable, but a new home utilizing it is much less likely to catch fire.

Homes are burning much faster, and fires are far more dangerous to firefighters. Less lives are being lost due to smoke detectors and improved firefighting.

Modern Family Homes Are Bigger, Full of 'Fuel'

Thanks to the extra belongings that we cram into our homes and the synthetic materials our things are made of, researchers say, our homes are burning down faster than ever before.

And even beyond the stuff that fills our homes, firefighters say the cheaper, energy-efficient materials used to build our homes can make firefighting even more dangerous.

https://abcnews.go.com/Technology/modern-furnishing-homes-burn-faster/story?id=12806666

"Yes, engineered lumber may be more flammable, but a new home utilizing it is much less likely to catch fire."

Using more flammable materials to build a home makes the home less likely to catch fire? How so?

Glad I have my own sawmill. If I build a house in my retirement it will be held up by 4x4 oak posts. You can't put a nail into them but it won't fall down. :-D

"Using more flammable materials to build a home makes the home less likely to catch fire? How so?"

DavidR:

You have a 100-year-old house built with sawn framing. I have a new home built with more flammable TGIs, but I have fire stopping and insulation in my stud bays, my electrical is up to code, and I have hardwired smoke alarms. Which of us do you think is going to suffer a serious fire sooner, please.