You’ve just finished cutting and installing your new natural stone tiles. What next? Time to grout the spaces between the tiles, right? Wrong! Before you even start thinking of what kind of aggregates will go into your grout, you’ll first of all need to seal your stone tile surface to prevent the grouting process from affecting your stone surface. The reasons and proper process for sealing stone tile surfaces before grouting are discussed in detail in the next sections; along with a brief discussion on sealing grout lines.
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Do you need to seal stone tile before grouting?
Yes- it’s necessary to seal raw stone tiles before grouting- to prevent the grout from sticking to your tile surface. All-natural stone surfaces- whether polished, honed, or antiquated- are permeable; and sealing before grouting helps cover up the pores and protect the flooring.
Since grouting is a messy process, you’ll end up with some grout on your tiles. You’ll want them sealed when that happens, as grout on an unsealed tile surface can discolor the stone surface. This happens when tiny grout particles, which are usually difficult to remove, penetrate the porous natural stone surface.
How to seal stone tile before grouting
To properly seal your stone-tile flooring before grouting, we recommend following the general two-step procedure detailed below:
Clean the tile surface
First off, you’ll need to clean off any debris or mortar leftover from the tile-installation process. To properly do this, use a commercial stone tile cleaner that will effectively eliminate all surface residue. Simply mopping the flooring with water and a mop will not cut it! With a basic mop-job, you’re likely to leave behind small dust particles that will end up locked in within the tiles’ micro-pores once the sealant has been applied. This usually results in an unsightly, smeared appearance.
You’ll also need to ensure that all residual moisture from the cutting stage of the installation process dries out before you begin sealing your stone flooring. Residual moisture may also come from the tile adhesive applied during tile installation. Applying a sealer to a tile surface that’s still laden with residual moisture will most likely result in patchy coloration that’s usually an eyesore.
Seal the surface
After cleaning the surface, use a soft pad or sponge roller to apply your stone tile sealant, but stop once the surface can’t absorb any more. This is usually after about twenty minutes. Also, ensure to buff away any excess sealant before the surface dries up. Depending on how porous your particular type of stone tiles are, you may have to apply multiple coats of sealant.
How long should tile sealer dry before grouting?
After sealing and buffing your natural stone floor, give the sealer about three hours to completely dry up before grouting. Though- most commercial sealants usually dry up about one hour after application. You should also avoid cleaning the surface for up to 72-hours.
Can you use a stone sealer on grout?
Tile grout lines should preferably be sealed using grout sealer and not a stone-tile sealant. There are two types of grout sealers, as discussed below:
Penetrating Grout Sealers
These are water-based and easily penetrate the porous, cement-based grout. Penetrating sealers are the best choice for grout protection in bathroom and kitchen areas where the floor is often wet.
Membrane-forming Grout Sealers
Also referred to as surface grout sealers, these types of grout sealants coat the grout surface to keep of water penetration. Surface sealers are great for coating grout lines on unglazed, natural stone surfaces. They aren’t recommended for use in coating bathroom grout lines- however- as they prevent evaporation of moisture trapped beneath the grout.
After choosing your preferred tile grout sealer, you can apply it by either pain-rolling or spraying it along the grout lines. With paint-rolling, it’s easier to ensure that the sealer stays closer to the grout lines, without smearing the tiles. Spraying- on the other hand- is more likely to leave your stone tiles stained, and will most likely require a thorough- cleaning effort from you to get the stains out. Spraying may also leave some areas along the grout lines not covered by the sealant as required.
North American Tile Cleaning Organization: Tile and Grout Sealing.