How to cut down on sealer consumption with very absorbent surfaces
Some batches of Mexican tiles, sandstones, and other very porous types of materials turn out to be far more absorbent than is usually the case with typical batches. That does not mean there is anything wrong with the surfacing. It only means that these can vary from batch to batch. When this is encountered and you find that you are sealing significantly less square footage than the guidelines indicate - here is how to cut down on the gallonage needed and still do a good job.
This applies only to sealers classified as "penetrating", not to the coating types.
What you are doing with these sealers is some degree of "filling" the porosity in the surfacing with the "solids" portion of the sealer. The "solids" are the permanent component of the liquid that remains after it dries.
This filling needs to be done to strengthen very porous surfacing, but you do not have to keep pouring sealer into it in one application. The filling process does not need to extend below 1/8" unless there are structural weaknesses below that level and you want the sealer to improve that situation. There is a technique to make this more efficient. Do not apply thinly in an effort to use less sealer as that only results in a low quality job. Instead, try this:
This technique will use less gallons than if you keep pouring in sealer liquid trying to build gloss.
- Apply a puddle one time that is heavy and saturates into the surface. Do not keep applying sealer and trying to build gloss at this point. You may have uneven or no gloss, but that will be improved later.
- Wait 12 hours or more. The idea is to let that first well penetrated application cure before applying a second. This creates hardened material to support the next application.
- Apply the second application the same as the first and wait 12 hours or more for the next.
- Continue until you have the finish you want.