To continue with the home maintenance series, the next section that I evaluate on an inspection is the structure. This deals with mainly the foundation wall, floor slab, Joist, Beams, posts, basement stairs, etc., basically the members that support the home generally from the basement, but sometimes there’s only a crawlspace.
Most people don’t think of these items needing maintenance but a stone foundation most
definitely does. Annual inspection of limestone and mortar joints is recommended to identify areas of movement and/or areas of moisture intrusion. Moisture passing through foundation walls, mortar, or concrete will likely leave behind a chalky white residue called efflorescence. This is basically salts that the water absorbs from these materials. When the area dries this substance is left behind. Excessive moisture intrusion on a limestone foundation can lead to the breakdown of the stone and mortar joints. Re-pointing of select areas may be necessary as an ongoing maintenance item.
Block walls can have some of the same concerns. Any cracked mortar joints should be re-pointed as necessary. Stair-step and horizontal cracking with any differentiation may be a structural concern and should be evaluated by a qualified foundation specialist or a structural engineer.
The next item I look at is the framing, including the beams, posts, Joist, and stair framing. In my area wood destroying organism damage is common. This damage is usually found in the joist and beams. Sometimes powder post beetle and termite damage can be found on the posts. Keeping a clean dry basement is the best defense. While I do not do pest inspections, I can, and do identify areas of damage that is consistent with WDO damage. After I identify these areas of damage I look for any splitting or inappropriate notching of floor joist. Joist are not supposed to be altered in the middle one-third of the span. The bottom of the joist tension and the bottom is in compression and will fail (split) if altered inappropriately. No notching or holes can be located in this area.
The next item is the concrete floor slab and flooring system. Generally this is just checked for cracking and signs of settlement. The floor can tell you the area that moisture seepage has come from through staining as well. An examination of the base of the posts and any partition walls can also lead you to whether or not there was any past seepage or moisture wicking into these materials through capillary action.
And last, but certainly not least are the connections and overall construction of the stairs. Often times, I find that the bearing of the stringers is inadequate, also with 2 x 12
stringers over-cutting is a concern as this can cause splitting and result in failure of the member. Proper tread depths and open risers is also a common defect. Most older homes do not meet all of the requirements for safe staircases. Care should be taken when it comes to the stairs, handrails, and guardrails see this post for more info on that. Regular monitoring of the wood members for any splitting and moisture damage is also recommended.
It doesn’t take much time to perform the structural portion of the inspection, but it is an important aspect of the home inspection. Without an adequate, sound foundation, the biggest investment of your life may need 10’s of thousands of dollars in repairs or worse. One of the single most important aspects of this area is moisture control, and don’t alter structural members without consulting someone who is well versed in the design of your system. These items are only a few of the important aspects of a structural inspection. If you believe you have an issue with your foundation or support system, it is best to call in qualified professional to evaluate your situation.
Aaron M. Zuehlke is the owner and inspector at Zuehlke Inspection Service, LLC, a full-service home inspection company serving Southern Wisconsin. Specializing in Home inspection, Radon Testing, Mold Testing/inspection and Residential Thermal Imaging. He can be reached by email at Aaron@Zuehlkeinspections.com or by calling the office at 608-931-7485.