Outdoor fountains are often made from durable concrete or moulded 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 centre.
Clean the surface of the outdoor fountain with a scrub brush and concrete cleaner to remove loose debris, grease and dirt. Rinse the concrete fountain with a power washer to remove all of the suds and dirt. Clean terra cotta fountains with any degreasing cleaner. Power washers may be too strong for terra cotta fountains; rinse terra cotta fountains with a water hose instead. Allow the clean fountains to dry completely.
Stir the sealer in liquid containers, shake sealers in spray cans 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. 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. Omit this step and skip to Step 4 if you are applying the sealer with a paint brush.
Dip the paint brush into the sealer and apply a light coat onto surface of the fountain reservoir. 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 using your choice of application methods. Wipe off excess terra cotta sealer. Allow the sealer to dry completely.
You should not seal newly constructed concrete or terra cotta fountains immediately. Wait for one week before sealing new concrete and at least 72 hours before sealing new terra cotta. The material must have time to cure properly or the sealant will not stick to the surface.