Most homes in Fairfield County, CT and Westchester County, NY have wood frame structures. This makes sense because wood is available, affordable, and fairly easy to assemble. Additionally, wood frame homes are much easier to add to or alter than stone, concrete, or steel homes.
But what performance should we expect from a wood frame structure over time? What are indications of serious problems?
All wood bends with age. Wood is forced to compress under constant load, deflect from intermittent load, and change shape with variations in temperature and humidity. Movement from these causes is usually not reason for concern.
Similar movement patterns can also occur from weakness developed from termite damage, water damage, or amateurish alterations. Sometimes original built-in defects are ultimately discovered by following up on sagging or cracking.
Progressive deterioration is most important to identify because it can eventually result in structural failure. Be careful with logic like “it has stood for 80 years so it must be strong”. Don’t forget that every building that ever collapsed stood up until it didn’t!
So how do we know if the sags, cracks or bumps are serious?
A home inspector is trained to identify patterns that differ from the norm and can indicate serious lack of structural performance. If the cure is not obvious, they should recommend evaluation by an engineer. If the home inspector is an engineer, they can usually make a prescription on the spot. Sometimes, however, follow-up invasive investigation or mathematical analysis is necessary.