Understanding a Structural Inspection

by | Feb 22, 2022

The structural portion of the home inspection is ongoing vigilance. These observations are happening in the background during the entire duration of the physical and visual inspection of the property and structure. 

Reasons for a Structural Inspection 

Structural damage or defects could come in the form of improper building methods from poor construction practices and/or low-grade or defective building materials. Outside forces could also play a role in structural decay such as wood-destroying insects, pests such as rodents, or exposure to moisture. These observations are made throughout the inspection whilst in the process of completing the visual inspections on all areas of the home, both inside and outside.

When it comes to construction practices, the inspector is looking for good mechanical connections between materials. Mechanical connections are in reference to the hardware and fasteners used during construction. In some cases, the wrong fasteners or strappings are used, which could allow building materials to detach from one another which would result in a structural failure if not caught early enough. In other cases, there can be an objection from a builder or contractor because they feel that the hardware they used is good enough. In these cases, it is the inspector’s job to remind the objector this is a “best practices” inspection. Often, the one who objects wants the inspector to site building code on his or her findings, but this is not the job of the inspector. The inspector is solely looking out for the client’s (oftentimes the buyer of a property) best interest. Heath and safety are paramount.

Common Concerns Found During a Structural Inspection

Should a structural error or observation be of interest to the inspector, there may be signs around the house that there is something not quite right with the structure, whether that be from the initial time of construction or an action a current or past occupant has done to the structure. Some observations that have been made in the past have been when an older structure that was built over a crawlspace originally has had the soil below the structure dugout in an effort to create a basement post-construction. This idea rarely works as intended due to the shortsightedness of the person who has decided to remove this soil. With the supportive soils reduced below a building, the foundation can shift due to a shift in the unretained soils below the foundation or pier pads. As gravity pulls down on an object above the soil line, the pressure downward radiates outward at a perfect 45-degree angle. Once a void is developed inside the 45-degree downward angle, the pressure from above can shift soils due to a lack of support from adjacent soils being removed. The soils can cascade downward loosely and the structure above effectively sinks. Cracks in interior plaster walls will develop, doors will fall out of plumb and operate poorly hitting the jambs or floors when operated, windows could be stuck in the position they were in when the movement occurred or glass could crack. These examples are all noticed by the inspector even before he or she enters the crawlspace below the house.

Another common structural issue is when a bathroom is remodeled. Often times the remodeler will change the position of the tub or change the tub into a shower. Once this fixture’s position is changed, the drain may line up directly over a floor joist. To get the plumbing drain to set properly may require the floor joist below to be cut. This action, without proper supports added below, will result in the settlement of the floor as the joists below are no longer secured in a structural position. In the interest of getting the job done, getting paid, and moving on to the next project, the person responsible may, sadly, just ignore the structural stability and cover it up. A bathroom and its fixtures add a lot of dead weight to the floor and supportive joists below. In time the surface will fall out of plumb and the floor may start to slope and/or bounce due to the damaged structural floor joist.

These are simply two of the most common structural concerns this inspector has observed. There are more observations that have been made on a daily basis, and the one thing they all have in common is that their symptoms were observed inside the house before the inspector ever laid eyes on the damages below. This is not to say whenever a potential buyer walks into a house and notices some wall cracks or floor slopes, that the structure is bad, but the observations need to be reviewed further to see if they can be repaired within an acceptable budget.

Wood Destroying Organisms 

Wood destroying organisms can also play a part in structural stability. Insects that eat wood leave behind a trace known as “frass”. Frass is the wood debris that insects develop either through digestion or just the waste left behind after they have bored through the wood. Not all wood-destroying insects eat the wood they are cutting through, but just like a saw leaves behind sawdust, insects leave behind piles of frass. Carpenter ants are the most common wood-destroying insect in the Pacific Northwest, but we will also occasionally see termites and their tubular travel structures as well as wood-boring beetles. All three of these insect examples require the wood to have a moisture level of 20% or higher. This is why moisture intrusion or poor ventilation is a concern to an inspector during an inspection. A good inspector understands moisture content and how moisture can enter into or below a structure.

Get a Structural Inspection with Octopus Home Inspections

If you’re in the Portland Metro area (Oregon) and looking for a quality home inspector, contact Octopus Home Inspections. Octopus Home Inspections is committed to upholding a strong code of ethics, including professionalism and integrity. Our home inspections are extremely thorough, fairly priced, detailed, and accurate. We provide each client with a comprehensive written report, document our observations with numerous color photographs, and offer unlimited follow-up support to ensure any and all concerns you may have are addressed. Check out our google reviews for more information. We look forward to hearing from you.