Outdoor fountains are often made from durable concrete or molded terra cotta. By nature, both concrete and terra cotta are absorbent materials which means that water can seep through the surface if the fountains are not sealed. Sealing concrete or terra cotta fountains is not complicated but it is a necessary aspect of fountain construction. Select the appropriate sealer for the surface of your fountain at your local garden supply center.
Clean the surface of the outdoor fountain with a scrub brush and concrete cleaner to remove loose debris, grease and dirt. Rinse a concrete fountain with a power washer to remove all of the suds and dirt. Clean a terra cotta fountain with a degreasing cleaner and rinse it with a water hose. Allow the clean to dry completely.
Stir the sealer according to the manufacturer's instructions. Add liquid sealers to a spray applicator or pour them in a small bucket for brush applications.
Apply spray concrete or terra cotta sealer to the inside and outside surface of the fountain reservoir. You can do this by spraying, or you can use a paintbrush.
Hold the spray applicator between 6 and 8 inches from the surface of the fountain reservoir. Depress the spray lever and move the spray can or spray nozzle in a smooth left to right motion until the entire surface is covered. Wipe off excess terra cotta sealer with a soft cloth. Allow the sealer to dry.
Dip a paint brush into the sealer and apply a light coat onto surface of the fountain reservoir, if you decide to brush the sealer. Continue to wet the brush with the sealer and apply it to the fountain until you cover the surface.Wipe off excess terra cotta sealer with a soft cloth. Allow the sealer to dry.
Add a second coat of sealer to the outdoor fountain reservoir. Wipe off excess terra cotta sealer. Allow the sealer to dry completely.