Composite terraced window wells: built-in steps, no rust clock, and what they cost installed here

A composite terraced window well is a molded polymer shell with a stepped back wall, and it solves three problems a corrugated steel well leaves open: it does not rust, it is stiffer against the push of expansive clay, and the steps are built into it. In Fort Collins those three things matter more than the marketing does, because the soil here is clay over the Pierre Shale and most bedroom wells are deep enough to need a code exit. Installed as a replacement, the well portion sits in the upper half of $1,100 to $3,300; in a full egress install it adds roughly 15 to 30 percent over steel inside the $3,800 to $7,000 range.

What it is

A one-piece or stacked molded shell, usually in an earth or stone tone, wide enough and deep enough to meet the 36-inch, 9-square-foot egress minimum with the tiers included. The back wall steps back in two to four terraces. Each terrace is a step up and out, and a ledge that can hold gravel or a plant. The flanges bolt to the foundation like a steel well. A fitted cover or grate sits on the rim.

The thing to understand is that the terraces consume projection. A terraced well is wider and deeper in plan than a steel well serving the same window, because the 36 inches of clear projection has to exist below the first step. That means a bigger dig, which is part of the price.

Where it earns its money on Front Range clay

Deep bedroom wells. Fort Collins and Larimer County both work to a 30-inch frost depth, and a basement sill within 44 inches of the floor puts most egress wells past the 44-inch line where a ladder or steps is required. Steps molded into the well are easier to climb, easier to inspect, and do not bolt through a shell that will rust around the bolts.
Wells seen from a finished room. If you are spending on a basement bedroom conversion, the well is the view from that bedroom. Terraces with gravel and a plant on them look like a garden. Corrugated steel does not.
Wet sites. A CSU study found roughly 10 percent of Fort Collins-area parcels at risk of high groundwater, most of them along the Poudre. A well that will be damp between storms should not be steel.
Soil push. The Colorado Geological Survey says the clays under populated Colorado can swell up to 20 percent by volume and exert up to 30,000 pounds per square foot. A molded shell with ribs and terraces carries that better than light-gauge corrugation. The caving well page shows what happens to steel that could not.

Where steel is the better buy

Shallow wells. Under 44 inches, no ladder or steps is required, and the terraces are decoration you are paying to dig a bigger hole for.
Utility windows. A laundry room does not need a garden view.
Tight sites. A terraced well’s larger footprint may not fit between a foundation and a property line, a sidewalk, or an air-conditioning pad. Steel with a compact ladder does.
A budget that has to cover drainage. If choosing composite means cutting the gravel column, choose steel and keep the column. Drainage is the part that decides whether either well works.

Pricing in this market

Scope	Range
Composite terraced well replacement, existing opening, with drainage column	upper half of $1,100 to $3,300
Full egress install with a composite well	$3,800 to $7,000, toward the upper half
Fitted cover or grate for a composite well	$175 to $650
Drainage rebuild under an existing well	$350 to $1,100
Fort Collins permit, passed through at cost	typically $150 to $300
Colorado engineer’s letter for a new or altered foundation opening	$300 to $700

The pricing page has every line, and the well cost calculator has a composite option that applies the premium for you.

How we install it

Same rules as any well here, because the soil does not care what the shell is made of. Excavate below the finished well bottom. Filter fabric and clean washed rock as a column that connects to the foundation drain where the house has one, which the City of Fort Collins guide requires of new wells, or to a deep dry well where it does not. Set the well on that column, flanges anchored into sound concrete, rock behind the shell rather than the clay that came out of the hole. Verify the terraces against the city’s stepped-option drawing: 18 inches maximum rise, 5 inches minimum run, 12 inches minimum width, 30 inches at the base, and 36 inches of clear projection at the centerline of the window. Grade away from the house, extend the downspout, fit the cover. Then follow CSU Extension’s advice for homes on expansive clay: keep irrigation off the foundation and let the terraces hold gravel or xeric plants, not a sprinkler zone.

The honest comparison

Composite is worth the premium on a deep bedroom well you will look at every day, on a wet site, and on a lot where the clay has already bent one steel well. It is not worth it on a shallow utility well or when it comes at the expense of drainage. The galvanized steel page covers the value case, the engineered kit page covers the case where the buck, window, and well should be one assembly, and the free on-site measure is where we tell you which your hole needs. We install all three across Fort Collins, Timnath, and Berthoud.

Frequently Asked Questions

What is a terraced window well?

A molded composite or polymer well whose back wall is stepped in tiers rather than a straight shell. The tiers double as the code steps out of the well and as planter ledges, so a deep egress well reads as a garden feature from inside the bedroom instead of a steel pit. The steps are what make it a code exit.

What does a composite well cost installed in Fort Collins?

The well portion sits in the upper half of the $1,100 to $3,300 replacement range, and roughly 15 to 30 percent above a galvanized well of the same size in a full egress install. The difference buys a well with no rust clock, more stiffness against clay, and steps instead of a bolt-on ladder.

Do the tiers count as the code steps?

They are designed to. The City of Fort Collins guide shows a stepped option with an 18-inch maximum rise, a 5-inch minimum run, a 12-inch minimum width, and 30 inches minimum at the well base. We verify the as-installed geometry on site, because the requirement applies to what is in your yard, not to a catalog page.

Does composite solve the clay problem?

It solves the rust half of it. A composite shell does not corrode standing in a wet well, and it is stiffer than light-gauge steel against soil push. It does not solve drainage. A composite well set on native clay with no gravel column still floods, and still puts water against your window.