Can You Seal a Prefinished Countertop?

Prefinished Countertop Types

• Many types of countertops come in prefinished varieties, are ready to install and have finished edges, eliminating the need for finishing and sealing immediately before or following installation. Prefinished countertops available to homeowners and builders include laminate, marble, granite and concrete. Tiles, which are applied to an existing countertop, are also usually prefinished with a surface that's ready for use after installation.

Sealing New Countertops

• Countertops with synthetic or non-porous surfaces don't require any type of sealing. The purpose of sealing is to penetrate the natural pores in the material, preventing water and staining agents from seeping into the countertop and leaving permanent discoloration. If you receive a marble, granite or concrete countertop, you can seal it regardless of whether it's prefinished. This gives added protection and creates a smooth, glossy surface.

Sealing as Maintenance

• Countertops made from porous material need occasional sealing as standard maintenance. The simplest way to decide when to seal a countertop is by placing a small drop of water on the surface and watching to see how long it takes to be absorbed by the surface. If the water seeps in within a few minutes, your countertop is vulnerable to stains. Sealing a new, prefinished countertop should delay the need to apply sealant in the future.

Procedure

• The process for sealing a countertop is the same whether it's a new prefinished surface, an unfinished surface or an old countertop in need of resealing. Sealant, which comes as a thick liquid, can only be applied to a countertop that's clean and dry. Spreading the sealant for even coverage with a brush or roller is important to give the countertop an even, consistent finish. Sealant typically takes several days to fully cure, so consult the manufacturer's instructions for when you can use your counters again.