What you see vs. what you can’t see

A damaged foundation yields several clues as to what’s happening, although it’s impossible to be right 100% of the time without seeing everything. Structural engineering becomes a branch of forensic science, good thing we have NCIS to guide us. Just kidding.

I receive lots of calls from clients who who want to know what’s happening to their house. Sometimes it’s for a pending sale, sometimes it’s for a refinance. Sometimes it’s just a homeowner who hopes their house isn’t collapsing. And some people prefer to stay in denial and not know, which is understandable. Foundation repairs can become traumatic events and who needs more drama?

Like any logic puzzle, we need to know how foundations work and what causes them to start failing. Once that is understood, then we need to know what the signs are that point to the root cause of the issues. Once the root cause of the foundation damage is addressed, then and only then is it appropriate to do repairs. What’s the point of repairing the symptom without the cure?

Foundations are simple creatures, just a monolith of concrete which transfers the weight of the building to the soil. The weight of the building is broken up into dead loads (materials) and live load (stuff moving around, or variable loads like snow on a roof). The soil has a rating for how much load it can succesfully manage, based on either adopted standards or testing from a geotech company. The foundations are typically block or cast concrete construction, reinforced with steel (rebar) and sitting on a footer (a wider chunk of concrete poured directly on the soil). The foundations go deep enough that they are below the “frost line”, or minimum depth where freezing rarely occurs. The foundation typically has a drainage sytem surrounding it to pump water away from the building.

So what happens that gets everyone up in a fuss? Cracks, water damage (efflorescense), cracks, bowing walls, cracks, water infiltration, cracks, tilting walls and of course cracks.

Cracks are indications of movement, the trick is to try and figure out what moved, which direction and why. In my experience, poor rain water management is responsible for 90+% of foundation issues. Either poor soil grading (water flowing towards, not away from the building), clogged gutters, clogged downspouts or damaged drain tile can be a source of too much water or insufficient drainage. This creates water pressure (commonly referred to as “hydrostatic pressure”) and foundation movement.

Other sources can be tree roots too close to the house, non-compacted soil under the foundation (we see this a lot in home additions), shifting concrete slabs pushing into the foundation, poorly designed and installed auxiliary structures like decks (putting piers too close to full basements), collapsing soil, expansive soil, rising water tables, etc.

In my opinion, almost anything that was built can be fixed. Foundation walls can be reinforced, sometimes they can be pushed back into place. Sinking foundations can be jacked back up, cracks can be sealed, water infiltration can be managed, and in extreme cases foundations rebuilt. Supplementary beams can be installed, and lots of other creative ideas are available that can save on the extreme expense of a foundation rebuild. But there is almost always a solution. In a future blog I’ll descibe what “almost” means (hint - sometimes there is no economical or practical solution).

In the next blog, or the blog after the next blog, I will be describing the types of cracks and what they indictate. There are many factors at work with failing foundations and good old fashioned logic and investigative work will yield the right cause. And once the cause is fixed, the remediation can begin. See you on the next blog!