This is one for the professionals. I would bring one in to look at it. And I agree with you, if at all structurally possible, keep the bay window. It's beautiful! Good Luck.

Time to call a professional(or two). Your window appears to have be cobbled on to the house. Are you also saying the basement joists are involved?! Hey, Ironwood - get a load of this !!(bad pun, sorry)

@studio10001: here is a photo of what the floor looks like from the basement where it's heaving.

Well. there's no real issue showing from below, if there is one( behind that insulation look OK? ).Your subfloor looks like it is still attached, not heaving, and the shallow split could have been there. If your husband isn't construction-savvy, I'd get someone to assess in person sooner rather than later.

Your house is "settling"
[I am assuming you do not live in a sinkhole prone area]

My granny experienced the same problem.
It was corrected by reinforcing the beams below the subfloor and then "jacking up" the house
at the low point.

Her home is concrete block [with stucco]. She first noted the problem when a crack appeared
in the plaster above a door at the front of the house.

That was 50 yrs ago.

Maybe. But that shouldn't be causing the window to pull away from the house.

The basement wall has cracks also.

I am referring to what is under the basement - the foundation of the house.

There is erosion or subsidence that must be addressed.

And I would conclude it extends outside the structures footprint.

Please take a picture of the joist at each end of the bay window opening above........I suspect along with your husband that the bay window has not been properly anchored. The outward forces of the window sagging maybe exerting an upward force on the first couple of joist that are running parallel with the bay window. In essence the forces are turning against the stringer joist and I suspect these forces are being transferred to the to closest parallel joist via the cross bracing.

I suspect the bay window was not part of the original framing, as the proper floor frame is not evident in your picture......

Check your floor levelness, by placing a 6' level down on the floor perpendicular to the bay window. Put one end of it a the base of the bay window wall. If you have any heaving in the floor, as evident by the level being able to rock over a specific point or the other end is off the floor........that pretty well confirms that yes you do have some heaving in the floor system and I suspect that it's the bay window that is the root of the problem.

It's not unfix-able, but it's not going to be cheap either.

I would strongly suggest you get a good contractor to come look at it on the site and be prepared.

Sorry, I didn't notice the other pictures you had.........and I was correct. This was added on at some time after the original construction. Your husband is correct. it's not properly anchored and the sagging or falling off the wall has transferred the forces via a turning moment and the result is the heaving.........I'm willing to bet when you put the level down on the floor you're going to find it.

Call a good contractor who will do it right this time..... and I would do it pretty quick.

Thanks, S. Thomas Kutch! I have checked the floor upstairs with a level and there is definite heaving parallel to the window. We also suspect the window was installed some time after the house was constructed and we don't think it was done properly. I wasn't sure if this was something we could figure out ourselves or not. My husband has been a roofer for 5 years and a drywall finisher for 3 years. He's quite handy around the house but this is starting to seem like a bigger project than we can handle. We just couldn't figure out the best way to secure the window with the other ones underneath it.

(The longer explanation of "cobbled"). Sorry this is happening and hope for the best for you.

Aja.... where are you seeing cracks in the foundation walls......? I see a crack in the dry wall below the window and I see what appear to be some dry wall joints in the basement (appears to be unfinished),, but I don't see anything that would indicated a settling foundation.........not from these photos.

Heather, there are a number of ways to solve the problem.......unfortunately, none of them are simply and will require opening up the wall and/or the floor. This is one of the problems that really needs to investigated on site for the proper solution.........it might be that the window can be re-hung using some cable supports at the top or it might be that the best solution is cantilevered joist below the window...........it's hard to give you the best solution without doing some investigating demo work to see what exactly you have to work with...........you need a good one site framing contractor's input here.

S. Thomas Kutch.

Not foundation wall but basement wall.

Is this usual?

[You see I live in Hillsborough County, where a sinkhole opened up last week below a bedroom and swallowed a poor man in the middle of the night. The search had to be abandoned due to the instability of the house.
The insurance inspector had checked out the home only a few weeks before.
So we are taught to be constantly vigilant in spotting cracks, doors that stick, etc.]

And granny lives in Pinellas and is unaffected.

Bay windows normally have a cable system attached to the seat board, running up inside the two mull posts and attached behind the bay window's roof to the house's sheathing. If you can remove the panel outside under the window you might see two bolts. If not the cable may not have been installed or has loosened up. If you see the bolts, put a wrench on it to tighten the cable.

S. Thomas Kutch,

I hope you understand why this subject scares the wits out of me

I will stop now commenting.

Aja, I understand.... I grew up in Florida and the unfortunate realities are that Florida sits on a layer of carbonate type rock.... this is the commonly referred to as the Florida Aquifer. Unfortunately, when you have a dropping water table (which you have in Florida) and you get an overabundance of surface rain and the resulting run off...........you're bound to get sink holes. The next time you're flying over Florida take a notice of all the round lakes you'll see........they're everywhere. The majority of which are nothing more than old sink holes..........

However, I'm pretty sure that this isn't the issue here, nor is a settling foundation as much as it's just a shoddy installation of the bay window.........the good news it's fixable. The bad news it will take some demo work and someone who can investigate the problem from top to bottom and knows how to fix it....and I doubt it will be cheap.

USF did a study prior to the development of Disney World to assess its future impact on the state.

I attended USF and I have studied the report.

A few things stand out

✔ the build up of the I-4 corridor and the strain on our natural resources,
✔ the depletion of the aquifer,
✔ the "death" of the Everglades

You will of course note that "sinkhole alley" now extends into Hillsborough County, much further south
than ever before.

Thanks for the input everyone! I appreciate the concern Aja and thank you as well! I'm very sure our foundation is sound. We live in the Canadian prairies far from and swampy or wet areas and this house was built in the 70's so it's had plenty of time to settle in. :P
I think this was a shoddy window installation. And thank you for mentioning the cables! I had never considered that. Im certain there's none in place but now I will definitely look into doing that properly.

Heather, I'm not sure about Real Estate laws there but once you know what needs to be done to remedy the situation, talk with your realtor about it. You may have a claim against the seller.

Good advice by S. Thomas Kutch! Yes Heather, no worries about sinkholes in the prairies. Are you in Alberta, Saskatchewan or Manitoba?

Heather, go to a store that sells bay windows and you should see how the cable system is installed. Sometimes the cable is included with a bay or sold separately, should cost about $20.