Composite Manhole Covers & Frames
Composite manhole covers and frames — UV-stable, corrosion-proof, and up to 70% lighter than cast iron. Round sizes from 17” to 44”. · 35 products
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About Composite Manhole Covers & Frames
When Composite Is the Right Call
If you’ve watched a cast iron cover rust through in three years at a coastal site or a chemical plant, you already know why composite exists. The materials resist UV degradation, saltwater corrosion, and chemical exposure that would destroy metal covers — and they do it at a fraction of the weight.
That lighter weight isn’t just about convenience. It means fewer lifting injuries for maintenance crews, easier installation without heavy equipment, and reduced shipping costs on large orders.
When to Choose Composite vs. Cast Iron
Choose composite when: The site has salt exposure (coastal), chemical exposure (industrial), prolonged UV (outdoor, unsheltered), or where the lighter weight matters for crew safety. Also the right choice for monitoring well covers that don’t need to handle vehicle loads.
Choose cast iron when: The cover will bear vehicle traffic, is in a roadway, or needs maximum load-bearing capacity.
Locking Options
- Cam-lock — Quarter-turn locking mechanism. Faster than bolts, provides tamper resistance without tools.
- Lay-in — Standard drop-in for easy access.
- Lid-only — Replacement lids available if your existing frame is in good condition.
Available Sizes
Round composite covers from 17” to 44” diameter. Frame depths from 5” to 19”. Lid-only options available for frame-only replacements. Call (866) 514-3684 for help matching sizes to your installation.
Related Categories
- Cast Iron Covers — For load-bearing, vehicle-traffic applications
- Manhole Accessories
- All Manholes
Frequently asked questions
What is a composite manhole cover?
A composite manhole cover is molded from fiber-reinforced polymer resin instead of cast metal. The result is a cover up to 70% lighter than cast iron that won't corrode in salt or chemical exposure, is UV-stable outdoors, and has no scrap value — so it isn't a theft target. Our composite line runs from roughly 10” to 44” round, in lay-in, cam-lock, and lid-only configurations.
How much does a composite manhole cover cost?
Composite covers and frames in this collection range from about $323 to just over $3,000. Smaller-diameter lids sit at the low end, while large 39”–44” frame-and-cover assemblies occupy the top of the range. Lid-only replacements cost meaningfully less than complete frame-and-cover sets, so if your existing frame is in good condition, replacing just the lid is the economical route.
What is the best material for manhole covers?
It depends on the exposure. Cast iron remains the best choice for roadways and anywhere vehicles cross — nothing matches its load capacity per dollar. Composite wins in corrosive settings: coastal salt spray, chemical facilities, wastewater sites, and unsheltered UV exposure that destroys metal covers. It also wins where crew safety matters, since a cover that weighs a fraction as much means fewer lifting injuries during routine access.
What is a fiberglass manhole cover?
Fiberglass-reinforced plastic (FRP) is one of the most common composite constructions, so "fiberglass cover" and "composite cover" usually describe the same class of product: a polymer resin matrix reinforced with glass fiber. The construction delivers corrosion immunity and light weight that cast metal can't. If a project spec calls for FRP or fiberglass, the composite covers in this collection generally satisfy it — check the product page to confirm the specific rating you need.
Are composite covers strong enough for vehicle traffic?
Composite covers are rated for their specific load applications, but they're generally not specified for heavy vehicle traffic. For roadway installations, cast iron is the standard. Composite is ideal for pedestrian areas, monitoring wells, and protected utility access where corrosion resistance and lighter weight matter more than maximum load capacity.
Do composite covers fade in the sun?
Our composite covers are UV-stabilized to resist fading and material degradation from prolonged sun exposure. This is one of their key advantages over coated metal covers in outdoor, unsheltered installations — there's no paint or coating to chalk, peel, or rust through, and the color runs through the material rather than sitting on the surface.
Can I buy just a replacement lid?
Yes. We carry lid-only options for most composite cover sizes. If your existing frame is in good condition and properly seated, you can replace just the lid without disturbing the frame installation — a faster, cheaper fix than excavating and resetting a complete frame-and-cover assembly. Match the lid to your frame's clear opening diameter and seat style before ordering.