If you would like to finish the inside of a shed, you have a pair of options, depending on the composition of the structure. If the shed is made of wood, you can enhance its appearance by finishing it with the appropriate stain. If the shed is metallic, your only real option is to finish the interior of the structure with paint. Unfortunately, metal is ill-suited for adhesion and will not accept a new finish unless you pretreat it with a special base coating. Know the proper materials to use and the appropriate ways to employ them, or you will end up with eventual shedding.
Dust the interior shed walls with a broom.
Put on a respirator.
Protects areas you do not want finished by covering them with dust sheets and painter's tape.
Coat wooden shed walls with latex primer using a roller equipped with a nap cover. Use a galvanised metal etching primer if the shed walls are made of metal. Use a 3- to 4-inch paintbrush engineered for water-based coatings to apply primer to areas inaccessible to the roller. Wait four hours for the primer to dry.
Wash the painting tools with water.
Coat the primed shed walls with semigloss or gloss latex paint using the clean roller. Use the clean paintbrush to paint areas inaccessible to the roller. Wait two hours for the paint to dry. Add an additional coat if you have poor coverage.
Apply an oil-based stain to wooden shed walls using a roller equipped with a shed-free cover. Use a 3- to 4-inch paintbrush engineered for oil-based coatings to apply stain to areas inaccessible to the roller. Wait four hours for the stain to dry.
Wash your tools with white spirit.
Apply a protective coat of wood sealer to the stained shed interior using the clean paintbrush. Wait three hours for the sealer to dry.
Don't use a flat or satin latex paint on the interior of a shed, as these coatings are not resistant to stains and abrasions. Don't use an ordinary latex or oil-based primer on metallic shed interiors or the finish will flake.