Weather, property grade changes cause foundation movement
The foundation of your home supports and stabilizes the entire structure. But it’s not a fixed component of your home. Water, weather, soil conditions and building materials all play important roles in the integrity of a foundation and can contribute to foundation movement. When AmeriSpec Omaha and Lincoln inspects your foundation, we look at six main areas of concern.
1. The grade of the property.
As we arrive on the property, we look at the grade of the property. Is it the low house on the street? Is a negative or positive grade present? Is adequate drainage present for the property for the front of the home? We can identify these issues usually before we even get out of our vehicle. If negative drainage is present, we make a mental note to inspect for possible underground drainage systems during the home inspection.
Negative slope can also create the bowl affect. Picture a large hole in the ground. place a structure in the hole, then place loose fill up against the foundation. The undisturbed earth is compacted more than the loose fill, creating this effect.
Is the foundation poured walls? Block? Crawl space? Slab construction? Or possibly even wood construction? No matter what type of foundation walls are present, we look at the front porch for a possible negative slope. We also check for negative slope at the foundation grading, and inspect the gutters and downspouts for possible negative slopes, damage and missing areas.
We also look to see if gutter extenders are present. Along with the gutters, we check to see if large or mature trees are present to see if their branches and/or debris can block gutters. Mature tree roots will also affect the foundation if located to closely to the structure. All of these issues can and will have an effect on the foundation, regardless of foundation type. These areas can also generally be identified before entering into the home.
Ideally, the grading around the home would have a consistent moisture content to keep equal pressure on the home year-round. In northern climates like ours, it is not possible. But it is important that homeowners not let this area get too wet or too dry. Dried-out areas crack and make open paths to the foundation. When this happens, water can be allowed into the foundation and footing areas.
3. Property is located at a possible street creep location.
These areas are generally at T-intersections, cul-de-sacs, and at curves in the road or street — anywhere concrete has a negative slope toward the foundation.
Concrete will shift over time. If a driveway is attached to a house or garage that abuts a street that is located at one of these areas, that is when street creep happens.
Street creep can be identified by the expansion joints being compressed, missing expansion joints, no cuts in the concrete, raised or cracked driveways and/or garage floors. In some extreme instances this condition will crack the foundation, regardless of construction type. It is very important to identify this problem prior to buying a home. If caught early enough, it can be a relatively inexpensive repair. It involves cutting the concrete to relieve pressure and adding expansion joints at these areas.
4. Main/upper floor foundation movement issues.
AmeriSpec Omaha and Lincoln inspectors look for these signs of foundation movement:
- Cracks in the walls and ceilings.
- Broken thermopane windows.
- Raised or damaged flooring.
- Gaps present in wood flooring in old or new homes.
- Doors or windows that do not open or close properly.
- The upper edge of a door or window is not level.
5. Basement walls.
In the basement, we look to see if walls are finished or unfinished. On finished walls that are poured or block, we look for cracking or loose drywall and wall covering. If there are foundation issues in a basement, ceilings will crack. Tiled ceilings will also move.
Also during the basement inspection, we identify any moisture-damaged areas, especially at the corners of the rooms near the floor areas. We look at the basement windows and window trim for any bowing. We also look at the basement floor, because movement at the floor can sometimes be related to foundation movement, especially in older homes.
For unfinished walls/crawl spaces that are block or poured concrete, we look at the frost line for movement. The frost line is generally 18 to 24 inches below grade. This is the most common area for cracking. If movement is present, we place a 4-foot level centered on the crack. If there is 1/2 inch or more movement at the top or bottom, then repairs are necessary. All cracks need to be sealed, ideally at the exterior, to prevent moisture penetration.
Also during a basement foundation inspection, we look to see if the sill plate is uniform across the top of the basement wall. If movement is present, the corners will be uniform, but the center will have moved inward. This is possible to see in all foundation types. If sill plate movement is observed, we check for cracking at the corners and possibly wall shear in homes that have block foundations or crawl spaces. Wall shear results when the second row of blocks shifts away from the first row of blocks. (The first row is held in place by the basement floor.) Repairs are always necessary if wall shear is present.
For slab foundations, AmeriSpec looks for movement or heaving in the home’s floors. Gaps will also be present where the floor meets the walls. Free floating slabs with movement are very noticeable to a home buyer. If this issue has compromised the footing with cracks/gaps, repairs will be needed. Expansive cracking can be repaired by grinding the concrete or sealing cracks with self-leveling compounds. Removal or repouring may be needed in some instances.
6. Exterior foundation.
When AmeriSpec looks at the exterior foundation, we look at the corners, then at the middle of each individual wall. If the bottom edge of the exterior covering (wood, vinyl, metal or a composite) is not uniform along this area, then foundation movement is generally present. All exterior foundation cracks should be sealed. In brick homes, AmeriSpec looks for cracks or movement at all corners of windows, doors and garage doors. We also look at the area where the foundation meets the lower sill plate, as well as shear or cracking from one basement window to the next. If movement is seen in basement walls, repairs will need to be made. All areas should be re-tuck pointed to help prevent future issues. Footing reinforcements may also be necessary.
Drainage, house placement on the lot, neighborhood grade, street location, guttering, vegetation, property maintenance and drainage systems including sump pumps are all equally important items for an inspector to identify during a home inspection. These items can and will cause foundation issues. AmeriSpec inspectors are trained and certified in identifying these issues. For more information or to set up an inspection, please call us at (402) 393-3696.