Concrete garden ornaments exposed to wind and weather erode over time, so sealing prevents them from cracking and chipping. The best sealer for a concrete garden ornament depends on your climate because of the freezing and thawing cycles that ornaments may be subjected to. Choose from sealers that penetrate concrete or form a hard coating to prevent chipping and yellowing over time. Summertime is a good time to seal concrete because of moisture considerations.
Select a sealer based on your climate. Penetrating sealers allow the concrete to breathe, while others seal it completely so no water gets in or out. These are in the form of acrylic, polyurethane and epoxies. People who live in climates with frequent freezes in winter should stay away from waterproof sealers. The base of the garden ornament may soak up moisture over the summer and fall, and the moisture inside will freeze and crack the concrete.
Clean the garden ornament with a stiff brush. If the ornament is small, use an old toothbrush. Then use a hose to clean off the ornament and let it dry completely. Summer is a good time of year to seal concrete garden ornaments, because the sun and warmer temperatures will help evaporate any water that seeps inside the ornament.
Place a protective cover on the area the ornament rests on to avoid drips or spills. Read the directions on the can of sealer and make sure you follow them carefully to seal the ornament successfully. Make sure the weather will be dry for several days before starting the project. If the ornament is small enough, you could take it indoors to seal it, then let it dry before taking it outdoors.
Penetrating sealers soak into the concrete, provide good protection from the elements and do not change the appearance of the garden ornament. Film-forming sealers are acrylic, polyurethane and epoxies. Acrylic sealers are the most affordable, easiest to apply, fast drying and block UV rays so the finish will not yellow. Polyurethane sealers are thicker, more durable and cost more. Epoxy sealers are generally not used outdoors because they yellow and do not stand up well to sunshine. (See References 1)
If you seal ornaments indoors, be sure to work in a well-ventilated area.