You glance out at your window well and notice orange streaks spreading across the metal. Maybe the rust is just on the surface, or maybe the well is already bowing and flaking. Either way, your first instinct is probably to find a quick fix. A liner sounds like the obvious answer, but before you go that route, it is worth understanding what is actually causing the rust and whether a liner can genuinely solve the problem.
The Real Reason Your Window Well Is Rusting
Surface rust from rain and humidity gets a lot of the blame, but the most common cause of window well corrosion in Colorado has nothing to do with weather. It is electrolysis.
When a metal window well is anchored to a concrete foundation, it can make contact with the steel rebar embedded inside that concrete. That connection creates what engineers call a galvanic corrosion cell. Essentially, a low-resistance electrical circuit forms between the dissimilar metals, and the window well becomes the sacrificial component. The metal slowly deteriorates from within, often starting on the exterior side pressed against the soil, where it is completely out of sight.
This is a documented problem. QualCorr Engineering, a firm specializing in corrosion testing, investigated premature window well failures for a consortium of Colorado home builders and confirmed that galvanic corrosion cells form when wells are inadvertently shorted to foundation rebar during installation. By the time rust becomes visible from inside your basement, the structural deterioration has typically been underway for years.
Moisture and drainage failures accelerate the process. Poor drainage keeps the soil around your window well perpetually saturated. Blocked gutters, heavy snowmelt, and Colorado’s clay-heavy soils all contribute to standing moisture against the metal. Soil acidity adds another layer of corrosive pressure. The rust you see inside the well is usually the last stage of a process that began on the outside, invisible, long before it caught your attention.
Freeze-thaw cycles finish the job. Colorado’s dramatic temperature swings force water in the surrounding soil to expand and contract repeatedly through the winter. That movement breaks down the seal between the well and the foundation wall, opening gaps where water infiltrates freely and speeds up corrosion further.
So Can a Liner Fix It?
This is the question most homeowners ask, and the honest answer is no.
A window well liner is essentially a shaped insert, typically plastic or polycarbonate, placed inside a rusted well to cover the deteriorated metal and give it a cleaner appearance. For a well with very minor surface rust and no structural compromise, a liner can provide some temporary protection. But in most cases, it is a cosmetic solution applied to a structural problem.
Here is why liners fall short:
They cover the rust without stopping it. Oxidation continues behind the liner. The corrosion cell created by contact with foundation rebar does not care whether a plastic insert is in the way. The metal keeps degrading, and the well continues to weaken.
They can trap moisture and speed up deterioration. The gap between a liner and the existing steel creates a confined, damp space with poor airflow. That environment can actually accelerate the corrosion it was meant to slow down.
They do not address the root cause. Whether the underlying issue is electrolysis, failed drainage, a compromised seal, or a combination of all three, a liner does nothing to resolve any of it. When a structurally weakened well eventually collapses or allows water into your basement, removing the liner just reveals the damage that was building underneath.
Liners are not without value in every situation. If your well is structurally sound and the rust is genuinely superficial, a liner may buy you additional time. But they should be understood as a temporary measure, not a repair.
What Actually Solves the Problem?
When a window well has reached the point where rust is visible from the interior, the most reliable solution is replacement with a system designed to prevent the galvanic corrosion cell from forming in the first place.
Window Well Solutions uses a patented mounting system that eliminates direct contact between the metal well and the concrete foundation. By ensuring electrical insulation between the well and any grounding electrodes or rebar in the foundation, the corrosion cell never develops. Combined with proper drainage installation, water-tight sealing using a compressed gasket system rather than standard caulk, and custom sizing for your specific opening, a properly installed replacement well addresses every factor driving the rust.
A liner covers the symptom. A correct installation removes the cause.
Frequently Asked Questions:
How can I tell if my window well rust is a structural problem or just surface-level?
Surface rust is typically limited to spots or streaks and has not penetrated through the metal. Structural rust involves flaking, pitting, bowing, or soft spots where the metal has corroded through. If the well is pulling away from the foundation or showing gaps at the seal, replacement is the appropriate next step rather than a liner.
Is electrolysis really that common in Colorado window wells?
It is more common than most homeowners realize. Updated building codes that require ufer grounds as part of electrical grounding have increased the frequency of the problem in newer construction. The window well anchors to the foundation, makes contact with rebar, and the corrosion cell forms during installation before the home is even occupied.
Will a liner void any warranty on my window well?
That depends on the manufacturer and the installation. Some warranties are voided by modifications, including aftermarket liners. Check your documentation before installing a liner over an existing well.
How long does a rusted window well take to fail after rust becomes visible?
There is no fixed timeline, but visible interior rust typically means the exterior has been corroding for some time already. Depending on moisture levels, soil conditions, and whether electrolysis is involved, a well that looks moderately rusted could be structurally compromised sooner than expected.
Does window well replacement require a permit in Fort Collins?
In most cases, a straight replacement of an existing window well does not require a permit. However, if the work involves changes to the egress window opening or drainage system, permitting may apply. A professional installer can walk you through what applies to your specific project.
Ready to Stop Covering the Problem and Actually Fix It?
If your window well is showing signs of rust, do not wait for the damage to reach your basement. At Window Well Solutions, we serve homeowners throughout Fort Collins and the Front Range, including Severance, Longmont, Thornton, Wellington, Loveland, Berthoud, Broomfield, Johnstown, Westminster, Brighton, and Denver. We also offer specific solutions such as Denver Rusty Window Well Replacement, Arvada Window Well Replacement, Erie Window Well Replacement, Greeley Window Well Replacement, Lafayette Window Well Replacement, and Louisville Window Well Replacement. Our custom window well replacements are built to handle Colorado’s climate. Our patented installation system eliminates the galvanic corrosion that causes most window well failures, and every replacement includes proper drainage and a long-term watertight seal.
Contact Window Well Solutions today for a free estimate and find out what a lasting replacement looks like for your home.