Determining if you have a foundation problem with your home or other building is determined mostly by using your eyes and just good common sense. If you are starting to see cracks in interior drywall, windows that won’t close or open, doors that suddenly seem out of kilter or other abnormal things around the home your foundation may be the culprit.
If you do a little investigative looking, finding problems can be quite easy if they are actually present. Finding a sticky window or door does not mean your foundation is bad. It may be nothing more than humidity, loose hinges or a window that needs a spring adjustment. If you find all of sudden there are a great many items with a problem then it is time to look around. Drywall cracking is a pretty good sign that the building is settling and there should be a reason why. If it is a brand new building you may expect to see a few very minor settlement cracks. Slight cracks over doorways or window corners may be caused by wood shrinkage as well. Anything beyond these minor defects should cause some added concern.
Starting on the buildings exterior, slowly walk the perimeter and take a real good look at the exposed portion of the foundation walls. If you see cracks in the wall, inward or outward bowing, sunken soils against the wall, cracks in the brick face or bowed siding for example, these are all causes for concern. Make a note of the locations and proceed to the inside of the basement.
Go to the locations you noted outside and see what is happening on the inside. Inwardly bowed walls means there is ground or water pressure being exerted against the wall on the outside. A severely bowed wall can collapse causing severe structural failure. Small very thin cracks may be nothing more than normal concrete shrinkage as the concrete dried. Using a pencil, draw a line horizontally across the crack and large enough to see easily later on. Keep checking the crack from time to time to see if the pencil mark as moved and the two sides of crack line no longer match up. If the lines are now separated vertically, it indicates that the foundation is moving. If you see a larger crack, bigger than an eighth of an inch wide, this may mean severe movement has occurred. A structural engineer or architect should be called to inspect and advise if a repair is necessary.
Bowing of any wall is a problem. The wall may have been insufficient in design to carry the loads placed on it or it at least indicates outside forces are being placed against the wall above the design limits. Poor back filling procedures, large rocks or stumps being placed in the back fill against the wall are all reasons for wall bowing. An eighth inch out of plumb is more than likely the workmanship but is acceptable. I have seen walls two inches out of plumb in eight feet. That is bad news. In most cases the outside would need to be excavated to determine the problem and the wall be replaced. Another often overlooked cause of wall bowing is excess water pressure against the wall. Ground springs, improper grading, missing gutters and downspouts can all add huge amounts of water against a foundation wall. Again use your eyes. Footing drains which should carry away that water can become clogged with silt, be crushed during back filling work or have the open air end of the drain pipe plugged with dirt or grass. Look for the footing drain pipe outlet and make sure it is clear of all debris.
Loose basement lolly columns, gaps between the buildings sill plate and the top of the foundation wall or other things that may seem odd probably are. Talk to an pro to make sure your building is safe and sound.
Pete
Your Friendly Building Inspector
http://www.Wagsys.com
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