For what it's worth, I'm a (soon to be licensed) engineer in NJ, with my experience in structures (a.k.a. structural engineer). I am NOT a home inspector, building inspector, code official, etc...all of which serve their own separate purposes, and generally cannot comment on structural issues short of saying "get an engineer" in NJ. I've done my fair share of work with homeowners insurance companies for structural failures, as well as what they call "frivolous claims" (basically a claim someone files to try to claim something happened that didn't really happen). While I don't do too much of that work anymore, I still get plently of calls from homeowners and potential buyers of homes and commercial properties because of potential structural issues.
As far as houses are concerned...water is the enemy. Get it away from the house, make sure your gutters are clean, downspouts are clean and are diverting water away from the house and foundation. Ensure that any and all underground drains/downspouts are operating properly, not cracked/collapsed and draining water to either daylight or a proper pit/drywell. Also make sure the grade around the perimeter of the house is sloped away from the foundation. Surface water from rain or drainage that is allowed to pool near your foundation will impose excessive lateral pressures on your foundation wall within your basement that has a potential to cause the wall to collapse (this happens more often that you may think, at least in NJ). If you have a sump pump, make sure it's working, and the water that it pumps out is diverted away from the foundation as well...otherwise you're just spitting into the wind. Sump pumps should also have a battery backup. Power generally fails during a storm type event that may have excessive rain. If its raining cats and dogs and your sump pump is working overtime to pump all the water out from around your foundation, then the power goes out...you can quickly end up up creek without a paddle. If you dont have a basement, you should still ensure the water is diverted away from the house. You don't want to run the risk of flowing water undermining soil below your foundation, or changing the soil conditions below the foundation.
As far as cracks are concerned... Starting in the basement, vertical/stepped cracks are 'generally' not too much cause or concern. They usually are due to small amounts of settlement that occurred shortly after the house was built, with the following 3 caveats. 1.) There has been no change in loading since the house was built (i.e. No addition above the area where the crack is located), 2.) The soil conditions below the footing have not changed (i.e. no washout of soil below the footing), 3.) The soil was properly compacted prior to the footing being poured. That being said, with all things held equal, settlement cracks usually resolve themselves over time and become a non-issue. However, if settlement continues to progress, then the first item is to figure out why it is occurring. The next item is to figure out how to resolve. Resolving settlement issues is typically a costly process and can involve pouring a newer/larger footing below the existing footing (or lack thereof), installing a small push style piers, installing helical style piers (or perhaps a combination of all three depending on the situation).
Horizontal basement wall cracks are generally cause for immediate concern and can be a safety issue. These type of cracks are generally due to improper design/construction of the basement wall, as well as inadequate drainage of water from behind the wall (see above). These type of cracks can be catastrophic with respect to the house, if left unchecked. They can generally be fixed a number of ways. 1.) Install carbon fiber/kevlar straps on the wall. 2.) Install concrete block pilasters on the wall to brace the wall. 3.) Install steel beams on the wall, vertically, to brace the wall. 4.) rebuilt the wall. Each option increases in cost/time, etc. To that end, these repairs generally involve getting other trades involved to relocate or remove utilities along the wall that may be in the way of the repairs.
Cracks and finishes (drywall/plaster/mouldings/floors) are generally not too much cause for concern, unless they correlate with perhaps a settlement issue or some sort of underlying construction issue. Unfortunately, many times, they only way to find this out is by removing the finishes and checking whats below/behind them.
Sloping floors are sort of similar to cracks in finishes above. However, if the house is old (say 60 years and older) its fairly common to find uneven and sloping floors, as well as outdated construction techniques that will lead to sloping floors, or cracks in finishes. Cracks in basement floor slabs many times are due to temperature shrinkage during concrete curing and/or lack of expansion joints.
Besides those items, water can also lead to damage/rot to the wood structure if left unchecked for an extended period of time. The issue at this point is, the water may enter from the exterior (from the elements) or be due to a leaking water line, drainage line, excessive humidity build-up from dryer vents, bathrooms (hot showers), leaking steam pipes, etc. Some of these items may be VERY apparent, and others not so much.
Generally speaking, if you have access to the attic and roof structure, as well as the unfinished basement and first floor framing, you can get a good idea of the type of care and style of construction that the house was built with.
There's nearly an endless list of issues that may arise with a house, especially from a structural standpoint. Some issues are much more common than others...and A LOT of the time they are water related. The best thing I can tell you is to do your homework. Hire a professional for your own due diligence...make sure you have answers to all of your questions before you pull the trigger.
Feel free to shoot me a PM and I'd be glad to lend any assistance I can from afar!
Hope it helps (and I didn't scare you!)
-Ryan
