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Choices in coatings and sealers abound.  Choosing the right product depends on the condition of the surface to be treated and the reason for the treatment.  Understanding these variables and the products available are key factors in selecting the proper remedy. 
Sealers are typically used as protection against moisture infiltration.  There may also be a need to safeguard against discoloration or to allow for ease of surface cleaning.  Still, a coating may be used to mitigate the harmful infiltration of sulfates, chlorides or carbon dioxide. The latter is more prevalent in coastal areas prone to salty sea air. Or after the increased use of deicers during severe weather, such as that experienced over the past winter. Chlorides and sulfates can accelerate corrosion of steel rebar in concrete and metal architectural features in brick masonry.  Penetration of moisture to the steel reinforcing bars results in corrosion of the steel.  This in turn leads to cracking and spalling (separating) of the concrete surrounding it.  Deicing salts not only affect the concrete surfaces they’re used on, but have been known to infiltrate building facades at ground level.   Airborne particulates from such deicing chemicals have been found as far up as five or six floors.  There are specific sealers that can create a barrier against the harmful effects of these chemicals.
 
Environmental conditions should be taken into consideration when choosing a coating treatment.  Rain, heat, cold, freezing and thawing, condensation and ultra-violet light can all play a part.  Sealers need to reduce the amount of moisture penetration while still allowing for the evaporation of any moisture that does get in.  This is referred to as breathability and it can vary widely among different compositions of sealers.  If water becomes trapped in the substrate, weather conditions can lead to a pattern of freezing and thawing.  This repeated process can cause the substrate to crack and flake.  Such a condition can also promote mold growth on the building surface or cause blistering and peeling of the coating itself.  In areas where heavy direct sunlight is a concern there are applications that do not yellow when exposed to ultra-violet light. The quality of a building’s color is thereby maintained.  Pale colored surfaces are especially prone to such discoloring.
 
Still other coatings can protect metal and glass features by reducing leaching.  Leaching occurs when moisture permeates a masonry surface and evaporates back out leaving behind trace elements of alkalis.  Porous precast concrete walls containing aluminum-framed windows can also benefit from such a treatment.  In circumstances such as this it is important to understand the nature of the substrate and how it might interact with various sealers.
 
The success of a coating treatment is also dependent upon the preparation of the host surface.  The removal of existing leached elements, contaminants, aged, ineffective coatings, or prior chemical treatments is important.  An improperly prepared surface can influence the ability of a coating to form a proper bond.  Breathability becomes an issue if sealers are inappropriately layered.

Technicians at Exterior Diagnostic Services are experts at diagnosing problems in building facades and concrete parking decks.  The highly trained and licensed EDS team can be trusted to use state-of-the-art technology and materials to perform appropriate waterproofing and repair projects.