What Is a Foundation Wall and How Is It Built?

Consisting of several parts, your home's foundation is the most essential element of its construction. The foundation wall is just one part of the entire system, but its functions, construction methods, and code requirements are many. Whether concrete, block, stone, wood, or reinforced, the foundation wall that holds up your home must excel for the rest of the structure to last. 

What Is a Foundation Wall?

A foundation wall sits between the home's structural footing and the bottom of the first story, helping support the structure, and is usually made of concrete, stone, or masonry.

A foundation wall plays at least three vital roles that serve the needs of the rest of the house: 

Its first job is to transfer the weight of the house or load from the main structure to the footings that rest below the foundation wall. The footings rest well underground and do the heavy work of anchoring the structure, dispersing its weight, and keeping everything from shifting or sinking into the earth. The weight transfer means the foundation wall must have vertical strength. 

Secondly, the foundation wall holds back the surrounding soil and keeps it from entering the basement or crawl space of the home. The wall must have exceptional horizontal strength to accomplish this task while not sacrificing the vertical strength necessary to hold up the house. Differences in soil types and potential soil disturbance factors dictate how hard your foundation wall must work. 

Finally, your home's foundation wall must keep moisture from entering the basement or crawl space below the house. The wall must be impenetrable to standing water or vapor in the soil around the building. 

Why Proper Foundation Wall Construction Is Important

Foundation wall construction methods and materials vary by location, climate, soil types, and natural disaster potential. Its construction must meet the environment's demands to keep your home standing with its weight properly transferring to the footings. Without proper construction, the supported structure can suffer heavy damage if the foundation wall fails. 

State and local building codes regulate foundation wall construction to ensure the structure is up to the challenge depending on regional situations. The variables include soil types, water presence, weather expectations, and earthquake potential. 

Local structural engineers are often part of the planning and permitting processes regarding foundation wall construction. Because building a home foundation isn't a good idea for a DIY project, you'll also want a qualified local concrete foundation company on your team if you're building a home or addition.

Foundation Wall Types and Thickness

Several house foundation types exist, and except for slab-on-grade foundations, one common element between them is the foundation wall. Foundation walls also come in a few varieties. 

Basement Wall

Basement wall foundation walls are precisely as they sound. Basement walls typically contain some reinforcement, especially when taller than 8 feet. Older basement walls may consist of concrete blocks (CMUs), poured concrete, stone, or wood, while modern construction may use prefabricated concrete panels or insulated concrete forms.  

Basement walls are visible from inside the home and serve as a barrier between the soil and air-conditioned space in the house, whether the basement is finished or bare. The structures are generally as thick as the total width of the home's lumber frame, plus the wall covering and exterior siding. This measurement is typically at least 8 inches.  

Stem Wall

Stem walls are another type of foundation wall that transfer the home's weight to the footings. Stem walls are shorter versions of foundation walls that make up the crawl space walls below a house. These structures may include reinforcement or not and be vented or unvented to control moisture. 

Stem walls are at least partially visible from outside the home and in the crawl space and are typically 8 to 10 inches thick, depending on the home's construction style. Stem walls usually consist of poured concrete or CMU construction, but stone and lumber stem walls are common in older structures. 

Pier Foundation

While technically not a foundation wall, pier foundations also transfer weight from the home structure to a footing. However, piers are taller than they are wide and don't form a wall shape. Pier foundations often consist of CMUs with a thickness that meets predetermined building code specifications. 

You may find pier foundations under backyard sheds or other structures. However, you're more likely to see them in crawl spaces directly under a load-bearing wall or beam, supporting long spans between stem walls. 

Foundation Wall Problems

Foundation walls can suffer several problems due to inadequate construction, poor drainage, shifting soil, nearby construction, natural disaster, or a changing environment. While sometimes not an urgent issue, cracks in the wall, sticking doors or windows, or damp smells are typically the first sign of a potential foundation wall problem. More severe symptoms of trouble include bowing walls, extensive cracks, visible water infiltration, mold, or sagging floors.

Foundation Wall Repairs

Should you suspect a problem with your home's foundation walls, calling a local foundation repair expert is your first course of action. While foundation repair costs can get expensive quickly if left unattended, catching and professionally repairing problems early can save a lot of cash and frustration.