8 things a structural engineer checks in a foundation inspection

A structural engineer conducting a foundation inspection home visit evaluates the physical condition of your foundation to identify failures and recommend repairs. They examine how soil, moisture and building materials interact under the weight of the house. A thorough check maps the exact points of failure and outlines a specific fix. This can help you avoid buying repairs you do not need.

1. Crack patterns in foundation walls

An engineer studies the width, direction and location of every crack to separate normal concrete curing from active structural movement. Vertical cracks may be shrinkage, but only an engineer can tell whether a crack is harmless. Horizontal cracks are usually associated with a bowing wall, so have them evaluated promptly.

Stair-step cracks in block walls can follow the mortar joints and can come from wall movement, settlement or shrinkage. The engineer records gap sizes to determine which settling cracks are normal and which require a structural fix.

2. Bowing or leaning walls measured against a straight line

Wet soil can push against basement or crawl space walls. This pressure can push concrete block or poured walls inward. An engineer checks for bowing using a laser level or a plumb line dropped from the top of the wall.

To know exactly how far out of plumb the wall has moved, Mequon, Wisconsin's foundation standards measure wall deflection by averaging the measurements at both corners and comparing them with the center. Repair choices depend on how far the wall has moved, and your engineer and local building department decide what is allowed.

3. Floor levels across the house

A sagging floor can show an engineer where a foundation may be moving. They walk the main floor with a level or similar tool to map high and low spots. The engineer looks for sudden dips or a continuous slope toward one side of the house. A noticeable drop can point to a settling footing or a rotting sill plate below.

Mapping the floor elevations reveals hidden problems like sinking central beams or dipping perimeter foundation walls. The engineer draws a floor plan and marks the elevation changes in fractions of an inch. This grid provides a baseline to judge if the house is still moving during future checks.

4. Doors, windows and framing above the foundation

When the concrete foundation shifts, the wood framing resting on it twists. The engineer checks the operation of interior doors and the alignment of windows. Doors that stick or swing open on their own can indicate a shift in the floor below. A foundation drop can pull the header out of level and jam the door against the jamb.

Gaps between the baseboards and the floor can also point to a sagging joist. The engineer looks for diagonal cracks in the drywall radiating from the top corners of window and door frames. These upper clues help trace the problem down to the exact section of the slab, crawl space or basement causing the trouble. Damage in the living room can trace back to a footing problem in the basement.

5. Posts, beams and footings below the floors

In a basement or crawl space, the floor joists sit on a central beam and the outer sill plate. The engineer inspects these supports for rust, wood rot and proper bearing. A steel lally column might look solid but have a rusted base where it touches the damp floor. Wooden posts can absorb moisture and compress, dropping the beam and sagging the floor above.

The engineer also checks the footings under each post. A heavy point load needs a wide pad of concrete spreading the weight into solid earth. In older homes, posts resting directly on a thin concrete slab can punch through the concrete. The engineer determines if the existing footings are wide and deep enough to carry the house without sinking.

6. Grading, gutters and drainage around the house

An engineer walks the exterior perimeter to see where rain goes after it hits the roof. The ground should slope away from the foundation to carry surface water into the yard. Gutters must catch roof runoff and direct it through downspouts well away from the walls.

If water pools against the siding, water pressure can force water inside and soften the soil. The EPA advises keeping gutters clean and the ground sloped away from the foundation. Fixing a cracked wall without fixing the yard drainage can let the problem return, and the engineer may recommend regrading.

7. Crawl space or basement moisture

Dampness can rot wood framing and weaken mortar joints. The engineer checks for water stains, standing water and efflorescence, which leaves a white, chalky powder where water evaporates. Dark stains on the rim joist or the sill plate can point to condensation or a slow leak. Too much moisture in the air can also damage structural wood by feeding mold and rot.

The EPA advises keeping indoor relative humidity below 60 percent, ideally between 30 and 50 percent. A damp dirt floor in a crawl space can add water vapor to the house. Consistent high humidity may call for steps to seal and insulate the space, and your engineer or a licensed pro can advise on moisture control such as a dehumidifier before framing repairs.

8. Signs of past repairs and how they have held

Many older houses have seen some foundation work over the decades. The engineer evaluates any existing wall anchors, steel beams, carbon fiber straps or epoxy injections to see if a past repair is failing. Wall anchors with plates in the yard are one repair for bowing walls and need engineering and a permit. The original installer might have chosen the wrong method for the property.

An epoxy injection repairs a crack, but a bowing wall may need more. New cracks forming next to an old patch can mean the foundation is still moving. The engineer uses this repair history to understand the forces acting on the house. If previous owners installed carbon fiber straps and the wall still deflects, a simple interior fix may not hold.

Choosing an independent structural engineer

A sales pitch from a repair contractor is not an objective structural evaluation. You want an independent professional who sells only their technical opinion and does not perform construction work. NCEES says its Principles and Practice of Engineering exam, the PE exam, is designed for engineers with at least four years of post college work experience. Licensing rules vary by state, so check your state licensing board to confirm the engineer holds a current license.

Prepare for the inspection by clearing access points:

• Empty the closets leading to the crawl space hatch.
• Move boxes away from basement walls.
• Locate any past foundation repair warranties or permits.

Expect a formal written report after the inspection. Mequon, Wisconsin's foundation standards define site specific engineering as analysis by a registered professional engineer or architect to document site conditions and give repair recommendations. A report typically maps the damage and explains the cause. Foundation repair may need a permit, so ask your own building department what it requires, and give the report to licensed contractors for competing bids.