Ameren Missouri allows only approved encapsulated flotation on Lake of the Ozarks. The specifications are in Appendix B, section 7.4, revised June 30, 2025. The manufacturer names are published on Ameren’s dock requirements page. This page copies both so you can talk to a builder with the right vocabulary. It does not certify a product.
The names on Ameren’s page
As checked October 22, 2026, Ameren’s dock requirements page lists:
- Ace Roto-Mold
- Berrho Cable Dry
- Cello Foam / Permafloat / Dockmate, with a note that Dockmate is Overton’s brand of Cello Foam
- Diversified Plastics Inc.
- Eagle Floats by Hendren Plastics
- Formex
- Highland Flotation Systems
- Modular Concrete Docks, LLC
That is eight listings. If a name looks unfamiliar, trust the live Ameren page over this copy. Ameren also says a manufacturer can ask for a waiver by submitting samples and test results, at the manufacturer’s cost. A builder’s “it’s just as good” is not that waiver.
What the float itself must do
- Foam is extruded polystyrene, expanded polystyrene, or a copolymer of polyethylene and polystyrene.
- Density is at least 0.8 pounds per cubic foot, consistent, with beads fused and no voids in the shell.
- Water absorption is less than 3.0 pounds per cubic foot at 7 days on the Hunt Absorption Test, certified by the manufacturer’s literature or by a letter from the company president.
- The encasement is solid polyethylene or a polyurethane coating, watertight, at least 0.125 inches thick. The certification has to guarantee that thickness.
- Warranty of at least eight years against sinking, waterlogging, cracking, peeling, fragmenting, losing beads, and animal damage.
- A punctured float that exposes the foam is replaced immediately.
Ameren can field-test floats and can test manufacturers at the manufacturer’s expense.
How the float is attached
This is the bolt rule people sometimes attribute to boat lifts. In Appendix B it is the flotation attachment rule, section 7.5:
- At least 3/8-inch plated bolts
- Fender washers at least 0.120 inches thick
- Lock nuts
- Attached so the float can be replaced
- Outside J-bolts are prohibited
- Puncturing the shell to hang the float is not allowed without a specific Ameren approval
- The manufacturer’s own attachment method still applies
A boat lift has separate placement rules. Those are in the sizing guide. The bolts above are about keeping the foam on the dock.
Who installs it
Refoaming and any other dock work is done by a certified dock builder or the property owner, and only after a permit is in hand. Waste foam needs a disposal affidavit from the builder. The refoaming page is the quote path. The refoam versus rebuild page is the decision if the frame is as old as the foam.