Fort Collins Concrete Curbing

Curbing day looks nothing like a normal concrete job. No forms go up the day before. No truck backs into the yard and swings a chute. What shows up is a trailer, a small extruding machine that rides along the bed line, and a mix so stiff it holds its shape the second it leaves the hopper. If you've only watched a slab get poured, this will seem like a different trade.

We run curb through yards all over Fort Collins, from compact lots near Old Town where the beds hug the house to the wider landscapes around Fossil Creek and Registry Ridge. The install itself is usually one day. Here's exactly how that day goes, so nothing about it surprises you.

Layout is the part you get a vote on

We start with a garden hose. Laid on the ground, it shows the shape of the run better than any drawing, and you can nudge it until the curve reads right from the porch and from the street. That's the moment to speak up. Once the machine starts extruding, the line is set, and changing it means cutting concrete out.

After the hose comes paint, then a sod cutter or trencher opening a narrow strip along the whole run. The soil in that strip gets graded and packed. Curb is heavy enough to need firm ground under it, and narrow enough that a soft spot shows up as a dip within a couple of years. We watch for sprinkler heads and drip line as we go, because irrigation almost always runs exactly where a bed edge belongs.

The sequence on install day

• Hose line laid, adjusted with you, then marked in paint
• Strip cut and trenched along the marked line
• Subgrade graded and compacted the length of the run
• Stiff, low-slump mix batched on site and fed into the machine
• Machine walked along the line, extruding the profile in one piece
• Radiuses hand-shaped where the machine can't turn tight enough
• Contraction joints tooled every few feet while the concrete is green
• Color and texture worked in on the runs where you chose them
• Curing compound sprayed the same day, tools and spoil cleared out

What gets cleared before the machine rolls

Why the mix looks wrong, and what happens after we leave

People watch the hopper and get nervous. The material coming out looks like damp sand rather than the soupy gray they expect, and that's the point: a curb has nothing holding its shape but itself, so the mix has to stand up the instant the machine passes. Same cement, same aggregate, far less water. It also dries fast on a hot windy afternoon, which is why curing compound goes on right behind the crew instead of at the end of the day.

Joints matter more here than on most flatwork. A curb is a long, thin, unreinforced ribbon, and at the north end of the range the freeze and thaw swings work on it hard all winter. So we tool contraction joints every few feet. The run will shrink and it will move, and those joints give it seams to do it along. A run with no joints cracks anyway, randomly, and those cracks widen every season.

Then it's yours. Keep sprinklers off it for a day, hold the rock and mulch back until we say go, and let nobody drive across it for a week. Season-wise, April into October works, with fall a favorite because beds are cut back and the machine has clean sight lines. We stop once the ground quits taking compaction, since frozen subgrade under a narrow curb is a run that lifts by March.

The runs we get called out to fix are almost never cracked from cold. They failed where somebody skipped the trench and set curb on loose topsoil. Ten minutes of compaction per section is the whole trick.Straight from the crew