Can brick pavers be sealed?

The Brick Industry Association's Technical Note 6A, “Colorless Coatings for Brick Masonry,” dated August 2008, carries this line in its summary: “Application is not recommended on newly constructed brick veneer or cavity walls or on new or existing pavements using clay pavers.” The note's abstract scopes it to above-grade brick masonry, so a document written mainly about walls still names clay paver pavements by name.

Both halves belong in the same breath: the date, the scope, and the bullet. The note is not new, and it is not a paving manual. But when it reaches pavements it does not hedge, and it adds that “coatings applied to floors or pavements are subject to conditions different from those in brick walls.”

It is also explicit about who it speaks for. The note says “Clay brick masonry has physical and chemical properties that are different from stone, concrete or concrete masonry,” and that its recommendations “are applicable only to clay brick masonry.” That boundary is why the next question comes before any product.

In Florida the name brick pavers does not settle the material: Tremron, a Florida paver maker, uses it for concrete units specified to ASTM C936.

A concrete unit is covered by the concrete paver documents, where sealers are optional and chosen for their reasons, as set out under whether pavers need to be sealed at all. Telling fired clay from concrete sold as brick, and the cleaning rulebook each follows, is covered under clay brick versus concrete pavers for cleaning.

Reclaimed brick raises a harder version of the question, because a brickyard that has closed cannot be consulted; that case is under sealing reclaimed Chicago brick.

BIA does not deny the appeal. “Another common reason for using a colorless coating is to achieve a darker, wet or glossy appearance,” the note says, the finish the paver trade calls the wet look, and it grants that “By reducing the amount of water absorbed by brickwork, colorless coatings may help reduce staining and efflorescence.”

Then comes the cost. “If staining or efflorescence occur on masonry treated with a colorless coating, the stains and salts may be difficult or impossible to remove.” The white salt deposit in question is efflorescence, and under a coating it can be locked in rather than kept out.

The second cost is moisture. BIA says a film-forming product's ability to exclude water from the outside also slows evaporation of water within the masonry, and can result in clouding and spalling if the source of moisture is not addressed. That is why the note says to use only breathable coatings, with a water vapor permeability of 0.98 or greater as measured by ASTM E96, anti-graffiti products excepted.

Two more lines narrow the case. BIA says “water repellents are not a permanent solution and will require reapplication,” and that a repellent coating is not necessary to achieve water resistance in brickwork under normal exposures where material selection, detailing, construction and maintenance were done properly. Whether a darker color is worth a sealer on concrete units is a separate question, taken up under whether dark pavers need sealing. Clay brick's cleaning limits, pressure and acid included, are in the table under the cleaning rulebook for clay brick pavers.

Technical Note 6A's summary sets three conditions for anyone who goes ahead.

• “Consult the brick manufacturer prior to the selection of a coating.”
• “Select only coatings intended for use on clay brickwork.”
• “For paving, consider the effects of coating on pavement slip resistance and the abrasion resistance of the coating.”

Each condition names a party. The brick maker speaks for the brick. The coating maker speaks for its product, including how it behaves underfoot and how it wears, and no general figure for slip resistance on a coated brick pavement is printed here. The note itself, August 2008 and written for above-grade masonry, is where the brick association's position on the pavement question is written.