Crawl spaces are sometimes found in homes in place of or in addition to basements as a way to elevate them off of the ground which is important in damp areas. They also promote air circulation throughout your home and allow easy access to plumbing and electrical components for the purpose of maintenance and repairs. Crawl spaces play a key role in a home’s structural integrity as they bear the weight of the structure above through the foundation walls and the support columns. There are two basic types of problems that typically occur in crawl spaces. They are inadequate structural support and moisture.

Inadequate structural support can result from settling caused by weak supporting foundation soils or a lack of proper drainage. Both can cause the soil to shift and settle as a result of changes in moisture content and density, causing the supporting beams above to move or sink. No matter how strong the supports are, they can only bear what the soils beneath are able to bear. If the supports sink, then the floor will as well. Inadequate structural support design is a result of improper spacing of existing support columns or posts. If support posts are not properly spaced, then overloading takes place on the girders, or the large beams that serve as main structural members by supporting the floor joists above. Girders transfer the “load” or weight from the floor joists to the crawl space walls and support columns. Overloaded girders will tend to bend and sag, affecting the structural integrity of the crawl space.

Moisture intrusion in a crawl space can be in the form of standing water, condensation, or humidity and has the ability to cause many issues. In addition to the usual problems such as mold, mildew, and musty odors which all affect the air quality in your home, moisture also has the capability of damaging key structural components in your crawl space. When crawl spaces are damp, humid, or have experienced flooding, then they become an ideal environment for rot or damaging insects that feed on organic materials, both of which can weaken and deteriorate the wooden structural members such as the floor joists and girders. Infested or rotten girders will tend to bend or sag, once again affecting the structural integrity of the crawl space.

Jack Posts

Both inadequate structural support and moisture intrusion affect the structural integrity of your crawl space and translate to the living space above in generally the same way. Common signs of this structural support failure will be sloping, sagging, or uneven floors or will result in drywall cracking, usually around windows or door openings. While both of these crawl space issues can be resolved in the same manner with the installation of crawl space support posts or “jack posts”, it is important to note that the moisture and humidity issues will need to be addressed as well, if present, to completely resolve the situation.

Crawl space support jacks can be installed in failing crawl space structures as a permanent stabilization solution. Support jacks are adjustable, high strength steel piers that extend between an engineered concrete footing and the girders, effectively transferring the load from the girders to the concrete footer. A determination will be made as to how many jack posts will be necessary and at what intervals to properly span and support the structure above. A footer pad will first be poured to provide a solid base with the jack post resting on top of it. Each jack post is capable of supporting vertical loads in excess of 10,000 pounds. Hydraulic jacks will be used on either side of the jack post to return the floor to one inch past a level position. Once level, the jack post will be adjusted to the correct height and the girder will be lowered to rest on top of it. Severely damaged girders will need to be replaced or supplemented with sister beams. “Sistering” is simply a means of attaching more lumber or other material to the sides of the girder in order to reinforce it.

In comparison to foundation issues involving frost heave, foundation settlement, or bowing walls, installing crawl space supports is relatively easy, inexpensive, and a permanent solution to reinforcing joists and girders in structurally damaged crawl spaces. At Preferred Basement Solutions, we will take pride in restoring the structural integrity of your crawl space with minimal disturbance to your home!