My own crew built the road and I still paid for it twice
Seven lots on 31 acres, new 1,100 foot gravel road to county standard, cul-de-sac bulb at the end. I've built roads for other people for years, so this was supposed to be the part I did well.
The spec called for 8 inches of compacted aggregate base at 95% modified proctor over a prepared subgrade, with density tests every 300 feet. I bought base material from a pit 9 miles away instead of the one I usually use at 22 miles, because the haul saved me about $4 a ton and there were 1,400 tons. I never asked for a gradation on the material. It came in with more fines than I expected, we got rain on day three, and the tests came back at 91 and 92 percent through the first 400 feet. The inspector failed it, correctly.
We undercut 400 feet, hauled the wet material off, brought in the good pit's stone, and reran the tests. That cost $41,300 against a $138,000 road budget, and three weeks.
Then the second hit, which was worse. The county won't record the final plat until stamped as-builts are in. My engineer's office was slammed and took six weeks to produce them. Combined with the road delay, my recording slipped from late March to early June, which put my lot marketing past the spring window in a market where people shop for building lots in April and May. Two lots that I'd priced at $88,000 sold in September and October at $82,000 each. The other five carried into the following year at $1,900 a month of interest.
My own accounting: $41,300 of rework, $12,000 of price concession, roughly $11,000 of extra carry attributable to the slip. Around $64,000 on a deal I'd underwritten at $210,000 of profit.
What I'd do differently: get a sieve analysis on any borrow material before the first truck rolls, and put the as-built delivery date in the engineer's contract with a specific number of business days after final grade, not "promptly." And I'd stop treating recording as an event and treat it as a chain with three parties in it.