Basements, Crawlspaces & Foundation walls

• Foundation walls are constructed out of several materials such as poured concrete, cinder block, stone, and occasionally wood. The most common problem associated with foundation walls is moisture penetration.

Water Penetration:

• Approximately 60 percent of all basements and crawlspaces in this country suffer from some form of below ground wetness. Block foundations are especially vulnerable, with an 80 to 90 percent chance of leakage within the first 20 years”. It is estimated that 98 percent of all foundation walls will leak at some point during their life. It is rare that water penetration will cause structural damage, but a wet basement or crawlspace can be a major inconvenience causing damage to interior finishes, personal items and can lead to mold.
• Moisture problems in a home can be intermittent – leaking after every rain or, occurring only after heavy rain. Still, some homes may only leak during wind driven rains or during a spring thaw. In most cases, the damage that is caused gives no indication of frequency.
• It is estimated that 90 percent of all wet basement and crawlspace problems are caused by surface water (rain or snow) collecting around the building. Before investing thousands of dollars on a waterproofing system, it makes sense to get the water flowing away from the home first.

KEEP YOUR BASEMENT & CRAWLSPACE DRY!

Gutters and downspouts play an important role in diverting water away from the building.

• Clean the gutters and downspouts in the spring and fall (or as needed).
• Make sure that the gutters drain and are sloped towards the downspouts.
• Be sure the downspouts are extended well away from the foundation (4 to 6 feet is usually adequate).
• Improper grading around a home can be another factor in a wet basement. Re-grading the exterior landscaping to direct water away from the building rather than towards it, can be another effective solution to moisture problems. Ideally, the ground should slope down and away from the home at a rate of one inch per foot for the first six feet.
• Periodically inspect the soil around the perimeter of your home making sure that water is sloped away from the foundation.
• Any abnormal slanting, sloping or leaning of your floors, walls, or ceilings should be promptly investigated by a professional Contractor, A Foundation Contractor, or a Structural Engineer.

Any area under a home with less than full headroom is called a crawl space. According to many codes, there must be at least eighteen inches of clearance between the bottom of the floor joists and the ground and twelve inches under beams.Any area under a home with less than full headroom is called a crawl space.

• It is imperative that crawl spaces be kept dry. Crawlspace vents installed in the side of the structure that have been used for years have been found to be ineffective.
• Another practice that has been found to be bad idea is insulation being installed between the floor joists, if moisture gets into the crawlspace it will inevitably end up between the insulation and the structure resulting in mold and possible structural damage.
• The crawl space floor should be protected against moisture entry with a vapor barrier. Heavy plastic sheeting or concrete are common materials used.
• Today it is also highly recommended to insulate the walls and heat the area in the winter, if properly sealed and insulated, the heat has only one place to go, and that’s up to warm the floors, not to mention it help to keep pipes from bursting in sub-zero temps.

NOTE: The building science concerning crawlspaces has changed over the years, keeping in mind that the crawlspace is part of the house, and that what is in the crawlspace, is in the house as well.

• Best practices today recommend crawlspaces to be encapsulated with insulated walls, and that the air be conditioned.
• If the crawlspace is adjacent to a basement, keep any access points between the basement and the crawlspace open to allow air to flow between the two spaces.
• Keep these areas clean, dry and it’s good practice to periodically inspect the crawl space for signs of moisture or plumbing leaks.

Beams – The purpose of a support beam is to carry the weight of the floor and walls horizontally to the foundation or columns.

• Typical materials for support beams are steel, wood, or laminated plywood. Steel beams can be much stronger than wood and are much more resistant to rot, insect, and mechanical damage.
• Steel beams should rest on steel or masonry columns.
• The newer, laminated plywood beams can be stronger than the solid wood type. These beams are lighter and less expensive than steel beams.
• Wood beams can rest on wood columns.

Support Columns – The purpose of a support column is to carry the weight of a beam down to a footing.

• Typical materials for support columns are steel, brick, concrete block or wood.
• Every support column should have a concrete footing underneath.
• Periodically inspect wood beams or columns for moisture damage, pest infestation or warping (especially in crawl spaces).

Regardless of their construction, walls crack because they are overloaded or because the structure has settled or heaved. Vertical and angled cracks are usually caused by settlement or heaving. Horizontal cracks are more likely to be load induced or caused by side pressure.
Note: Hairline surface cracks that do not pierce the wall and are not accompanied by displacement are usually not structural in nature and should be distinguished from the cracks discussed here.

Vertical Cracks:

• If a wall has an upwards overload adjacent to a downwards overload, it may crack vertically so that one side rises or sinks with respect to the other. Vertical cracks are usually caused by settlement, compaction, or soil eroding under the footing. Overloading from above can occur when framing members fail forcing loads to areas that were not designed for them. Similar cracks can also be caused by overloads from below, such as frost or hydraulic expansion of the soil.

Angled Cracks:

• When up and down loads are applied so the forces are offset from one another, cracks are likely to occur at an angle. Cracks of this type may be found when there is a major discontinuity in the soil or if a building is built on expansive clays.

Horizontal Cracks:

• When a wall is overloaded from the outside, as from frost, soil pressure, or improper back-fill, it may bow inward and crack horizontally. In a block wall, the crack is usually in a mortar joint and is wider on the inner face. An additional cause of horizontal cracking may be settlement of the foundation. If a foundation is laid on top of unstable soil, the wall which lacks the proper support could drop resulting in a horizontal crack without vertical displacement of the wall surface.

Note: Surface effects such as poor grading or improperly located downspouts can increase the amount of water pushing against the basement wall.

Catastrophic Failures:

• Walls are strongest in compression. As a result, they prevent a catastrophic failure which occurs from vertical loading in the absence of a horizontal component. Failure generally occurs when a horizontal component of the load causes the center of gravity of the wall to move beyond its base. The center of gravity is the midpoint of the mass of he wall. Unless it is specifically constrained, an object will overturn if its center of gravity moves outside its base.

Signs of Possible Foundation Failures Include:

• Horizontal cracking
• Wall out of plumb
• Excessive bowing inward or outward
• Large vertical cracks (usually in excess of 1/4 inch).

If a tree isn’t the proper distance away from a house It’s roots can get out of control and clog sewer and water lines or cause cracks and damage to the foundation.

If a tree causes damage to the foundation of your home, you’ll need to call in a professional. The tree may have to be removed before the foundation is repaired. That’s why it’s important to do your homework. Determine how big a tree can grow, and how far the root structure can spread to avoid problems spouting up down the road. Here are some general tips to help prevent a potential root problem.

• Plant trees at least 10 feet away from the house, depending on how big the tree and roots will grow.
• Don’t plant trees above or near sewer or water lines.
• Consult with a structural engineer if you believe tree roots have damaged your foundation.
• If tree roots are inching closer to your foundation, consider installing a root barricade made of thick Plexiglas. It’s buried deep in the ground and can stem the roots from attacking your house.

Note: The Information contained within this website is for informational purposes only. Kevin M. Leonard & The Ohio Home Inspections Company always recommends that a qualified expert be consulted in the area of concern.