A covered slip is not a lake house with a hull under it. Ameren’s permitting page says permits will not be issued for houses or other habitable structures. Appendix B then lists the details people try anyway. The revision checked for this page is June 30, 2025.
Not allowed
- Habitable structures on the dock.
- Temporary or permanent enclosures used for living, entertainment, gathering, or similar uses.
- Sunshades or fabric installed to create an enclosure, even if they roll up.
- Toilets, showers, and any device that could put liquid or solid waste in the lake.
- Kitchen appliances, garbage disposals, dishwashers, water heaters, and sinks. The exception Ameren writes is a sink used only for cleaning fish.
- Storage that is walled or roofed beyond 80 square feet total per dock. Measure the outside.
Commercial marina ship stores and similar marina uses are a different category, capped at 200 square feet. Fishing enclosures are also capped at 200 square feet, and at least one-third of that floor has to stay open to the water, with no trap door over the opening. Those are not a back door to a guest suite on a residential dock.
What a roof still can be
A roof over the boat is a structure the floats must carry. The minimum roof live load in Appendix B is 11.5 psf, unreduced. Adding that roof to an existing dock is a modification: $550, drawings, and no work until the permit is issued. Describe it on the covered dock form as a cover, not as a room. If someone has drawn a bar, a bed, or a full bath, it will not survive review, and building it anyway is how a $2,000 enforcement fee starts.
Neighboring docks with older rooms are not a variance. Ameren permits the application in front of it.