Water Washed Soil From a New Footing in Naples. Now What?
Updated: 4 days ago
A builder in Naples was partway through a new one-story block house when surface water ran along the foundation, carried the soil away, and left the edge of the footing showing at several corners of the building. That is how the contractor reported it, and the photos showed it. The builder's grading contractor backfilled the low spots, but Collier County wanted an engineer's letter before it would schedule any more inspections.
The builder sent us the survey, the permitted plans and a set of photos and asked for help. We were not the engineer who designed the house (the engineer of record), and the letter would not change the permitted design. The question was narrow: is the foundation still sound, and is the soil beside it doing its job?
What the site visit found
An independent Florida professional engineer working with our office went out to the house.
On site he walked portions of the perimeter, paying attention to the corners where the washout happened, and hand-probed the backfill (the soil put back against the footing). It was firm. He found no soft or loose spots and no voids along the edge of the footing. The exposed concrete of the footing and the block walls above it showed no cracks, no movement and no other visible sign of settlement.
He also found that a good part of what looked like washout was not missing soil at all. It was concrete that had leaked out from under the forms during the pour and hardened next to the footing. In photos, that leaked concrete can be mistaken for washout.
His conclusion, in the signed and sealed letter: the condition was consistent with surface erosion of the soil beside the footing during construction, not with a loss of support under the house, and in his professional opinion the foundation had not been structurally affected. In his opinion, with the backfill compacted and a short list of work finished, the soil along the foundation will provide adequate support for the foundation as permitted.
The letter went to the builder the same day as the visit, ready to submit to the County.
Why the County cared, and what the paperwork showed
A footing carries the house down into the soil under it. If water removes enough soil from beside and beneath the edge of a footing, the footing can lose support and settle. That is why an inspector may stop and ask for an engineer when footings are exposed. On this job, Collier County did.
The builder also had paperwork on how the building pad was built. The pad had been filled and compacted in lifts (layers) and tested before the slab was poured. The density reports, a measure of how tightly the soil was packed, showed both lifts at 95.6% to 96.1% of maximum density against a 95% minimum. Those tests were done before the washout, so they say nothing about the new backfill. They report that the pad under the house met the required density before the slab went down. The hand-probing separately checked the new backfill at the edges.
The house sits on a monolithic slab, meaning the floor slab and the thickened footing at its edge are poured as one piece. The thickened edge is the part the water uncovered.
What to do if water uncovers your footing
Take photos before anyone touches it. Wide shots that show where on the building it is, and close-ups of the footing edge. The engineer needs to see what the washout looked like, not just the backfill.
Find your pad paperwork. The fill compaction (density) reports, the foundation survey and the permitted foundation plan. On this job the engineer reviewed all of them along with the photos.
Compact the backfill, do not just dump it.
Do not pour or cover anything new against the area until someone has looked at it. Once it is buried, nobody can see it.
Fix the water, not just the hole. Grade away from the house and get sod or erosion control down on the bare spots, which helps keep the next storm from doing the same thing.
Call an engineer early. On this job the County would not schedule more inspections until it had a signed engineer's letter. You can reach us through our Naples structural engineer page or the contact page.
FAQ
Does a washed-out footing mean my foundation is damaged?
Not by itself. In this case the engineer's finding was that the condition was consistent with soil eroding beside the footing, not a loss of support under the house, and the visible footing and walls showed no cracks or settlement. The only way to know on your house is to have it looked at and probed.
Do I need the engineer who designed my house?
Not on this job. Our office was not the engineer of record for the house. The letter said so plainly and did not change the permitted design. If you are unsure, ask your building department what it will accept.
What will the County accept?
That is the Building Official's call, every time. A good letter states what was observed, what documents were reviewed, what work is still required, and what the engineer's opinion is, with its limits spelled out. What the contractor reported and the engineer did not see is labeled that way.
Will the engineer dig or test the soil?
Not on this one. This visit was a look and a hand-probe along the footing, plus a review of the pad compaction reports and the survey. No excavation, coring or lab testing was done. We work across Southwest Florida, including Fort Myers and Naples.
Questions about a footing, a washout or an inspection hold? Call Michael D. Stewart, P.E. at 239.292.7670.
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