Analyzing basement cracks, shifts

Published on Times Herald on April 4, 2016

In the last couple of articles we have been discussing what I see and what you see when looking at the same area or item in a house. We have referred to this as “double vision.”

In the past articles, we have spent time looking at the exterior of the house, the property, the garage and attic.

Today, lets go down into the basement and see if we still experience “double vision” here.

I always look forward to going down into the basement because usually it tells me more about the house than any other area. If the basement is finished off into a living space, it is more difficult to observe the systems, but on the other hand it tells us about the past owner’s mentality as it relates to making improvements. Finished basements typically are done by someone other than the original builder, often show semi-professional workmanship and they have shortcomings and issues.

In most cases, however, the basement is unfinished, but often it is full of boxes, tools, exercise equipment and old furnishings. Many people enter this area, grab their forehead and say, “Where do I start?” Well, let me give you a tip on how to get started.

Basically, there are five major areas of concern down here. They are; the foundation, wood framing, electrical, heating and plumbing. You want to look at only one system at a time without getting distracted. Today, let us focus on the foundation.

You should walk around the entire perimeter with a flashlight and note any concerns. This area is quite simple. The major areas of concern are abnormal movement or failure and signs of water. When I start looking at the foundation, the first thing I want to know is what the walls are made of. Is it old fieldstone, masonry block or poured concrete? All three have different characteristics. The old fieldstone was most likely installed before there were codes and inspection requirements. Also, due to their age, they may have been around for more abuse from nature and past occupants. These walls are commonly damp, show evidence of past movement, probably have no waterproofing or any drain tiles. Also, any mortar is old and deteriorating in areas.

Masonry block wall concerns on the other hand are not as physically strong as others and have an interior open webbing that allows any water infiltration to move around inside the block. This makes analyzing any leak condition more difficult.

Poured concrete walls are the strongest, are a solid mass and are easier to analyze and repair.

Approximately 90 percent of all foundations have a crack somewhere. The type and size of the crack tells stories. Corner and diagonal cracks are considered more serious. Long horizontal cracks, approximately 4 to 6 feet above the floor, are caused by outside pressure being applied to the wall from a heavily laden soil, usually saturated with water. This condition commonly is caused by improper drainage or roof water overflow.

Years ago, I had an inspector pull a quarter out of his pocket and he tried to slide it into a foundation wall crack. I asked him what he was doing and he said, “If I can get a quarter in there, it’s too wide.” Very simply, the wider the crack, the more concern, but one should also look for or be aware of two directional movement. I always run my fingertips over the crack to see if I can feel a ledge or where one side of the crack is higher. The indication is that the wall is not only separating, but is being pushed in slightly for some reason. I have seen cracks like this caused by the weight of a nearby motor home and once by a fully loaded concrete truck pouring a new driveway next to the house.

Vertical cracks are the most common and a general rule in the industry is that if they are “hairline” in nature and not leaking, don’t worry about them. In general, cracks should be monitored for future movement and there are gauges and rulers available for that task.

Water stains also tell stories. Approximately 75 percent of all basements have or will have water infiltration at one time or another.

Corner dampness is the most common and is caused by outside downspouts that are plugged up or don’t have extensions to discharge the water away from the corner. Leaks around basement windows or window wells often show up because they are not maintained and any outside water is now overflowing. Long continuous stains, where the foundation wall meets the floor or where you see indications that water is coming up through floor cracks, indicates that the outside drain tiles are plugged up or were never installed properly. Many older homes don’t even have drain tiles. This condition often has to be remedied by digging up the outside of the house or installing an interior drain tile system. Both remedies are quite expensive.

If you have poured concrete walls and see round damp spots, they are probably from past leaking “rod holes.” This type of leak is very common, easy to repair from within and is relatively economical. Obviously, these were never properly sealed and they usually come in bunches. If you see one, look for more.

When looking at the foundation, one must also realize that the big steel beams holding up the wood framing are normally held up at the ends by the foundation walls. This bearing point is a high pressure area and often shows some type of stress and even leaks.

I consider the concrete basement floor a part of the foundation system because not only is it a walking surface, but it holds the bottom of the foundation walls from kicking in. So, one must always look at the floor to see if there is any heaving, settling or abnormal cracks.

Finally, remember this. If there are cracks and moisture, which is obviously common from what we have just discussed, the condition can lead to other concerns such as the formation of mold, deterioration of wood framing, rust of structural steel and infestation.

The foundation holds the house up, it is buried down into the earth, is susceptible to nature and all its forces and has more concerns than water infiltration and cracks. I believe that the “double vision” we experience here may be similar, but is more dependent upon focus and clarity.