Penetrating vs. Coating
Note: Penetrating type sealers are also known as "impregnators", "encapsulators", "penetrants". A coating type sealer is a "film former".

Generally, the following is true but may or may not make any difference to your choice of sealers. All the sealers do what they are supposed to do and should be chosen by the characteristics best suited to the job criteria.

Penetrating Sealers:

• Less prone to peeling due to bond below the surface, not just on top.
• Able to build a barrier to stop efflorescence.
• Can strengthen soft surfacing (if the solids portion is of the type to do that).
• Can fill small cracks (if the solids portion is of the type to do that).
• Can stop lime pops on Mexican tile (if the solids portion is of the type to do that).

Coating Sealers:

• Depend on the raw surface cleanliness and strength for good bond.

Note:
Sometimes, despite your diligent research and the best of intentions of your suppliers salesperson, you might have been given the wrong information. Therefore, no matter how confident you are, whether first time user or seasoned professional, it just makes good sense to patch test a small area and evaluate the results in a few hours before doing a large area.

Most Aldon sealers have more than one area they can be used in any project. Check sealer information on the web site.