Academy/Maintenance Fundamentals
Retaining walls
How to read a bulge, a crack, or an uneven settle correctly, and who is responsible for the wall in the first place.
A retaining wall usually fails slowly, from water pressure building up behind it, not all at once. Watch for bulging, cracking, or settlement that's worse in one spot than another. Any of these three signs is a trigger to call a structural or geotechnical engineer now, not to guess at severity yourself or wait for next year's walk-through.
What a bulge or an uneven settle is telling you
As part of your regular grounds walk-through, look at the face and top of every retaining wall for two specific signs. Bulging or bowing along the wall's face is a stress indicator, evidence the wall is being pushed harder than it was built to resist. Settlement is more nuanced: if the whole wall has sunk evenly along its length, that is generally a low risk to structural stability. If one section has dropped while the rest hasn't moved, known as differential settlement, that is a serious risk indicator and should not wait for the next scheduled inspection. Criterium Engineers' HOA-focused inspection checklist uses exactly this distinction to separate cosmetic wear from structural risk.
Why drainage is usually the real cause
Most retaining wall failures do not start with the wall itself, they start with water that has nowhere to go. When the soil behind a wall stays saturated instead of draining away, it builds up hydrostatic pressure, a sideways force pushing on the wall from behind. Inadequate drainage and the hydrostatic pressure it causes is one of the most common root causes of retaining wall failure, alongside problems with the foundation bearing on the soil below. Checking that a wall's drainage system, whatever form it takes on your property, is clear and functioning is one of the few things a board or maintenance staff can meaningfully verify without calling an engineer. Skipping that check does not just risk a bigger repair bill later; APPA links deferred maintenance directly to safety liability, not only cost.
Whose wall is it, and does it belong in the reserve study
Two separate questions live under one wall. First: who is responsible for maintaining it? That depends on your CC&Rs and any recorded easements, not on this lesson: some retaining walls are the association's common-area responsibility, others belong to the adjoining owner. Check your governing documents and plat map before assuming either way.
Second: does it belong in the reserve study? A component only qualifies for reserve funding if it clears four tests described by the National Reserve Study Standards: the association must be financially responsible for it, it must have a limited useful life, that remaining life must be predictable, and its cost must clear the association's own minimum threshold. A structural retaining wall the association is obligated to maintain can still be correctly missing from the reserve study, for example if its remaining life cannot be predicted the way a roof's or a water heater's can. Being off the reserve list does not take it off the maintenance list.
Check yourself
Answer before you read the explanation, recalling it is what makes it stick.
One 40-foot section of a retaining wall has settled three inches while the rest of the wall hasn't moved at all. What should the board do first?
A retaining wall has settled evenly along its entire length, with no bulging, cracking, or leaning. How should the board treat this on its own?
Soil behind a retaining wall stays saturated because its drain outlets are clogged. What is this most likely to cause over time?
Sources
- A Retaining Wall Inspection Checklist for Your HOA, Criterium Engineers
- Deferred Capital Renewal and Deferred Maintenance, APPA
- National Reserve Study Standards, explained, Association Reserves
Maintenance Fundamentals
See how a missed drainage check like this becomes a bigger bill in Deferred maintenance.
Who is responsible for a given retaining wall, association or adjoining owner, and whether that wall qualifies for reserve funding, depends on your CC&Rs, any recorded easements, and your own reserve study's criteria.