Debate over the causes of “spots"
Long ongoing debate over the causes of “spot etching” or “spots” or “pock marks” in plaster pools.
WHAT: Long ongoing debate over the causes of “spot etching” or “spots” or “pock marks” in plaster
pools. Both groups believe they hold the key to the answers. While disagreeing on the causes, both
parties agree that it is not the plaster itself, otherwise the problem would be even more widespread.
(**Plaster has to be mixed within a range of standards, resulting in different mixtures (some good/some
not so good). The only fix is re-plaster... acid washing will not remove the spots).)
WHO: At the heart of the debate we have the National Plasterers Council vs. onBalance. NPC believes
that bad water chemistry, or “aggressive water” as it is also known, is the culprit behind the spots.
onBalance, on the other hand, believes that the problem lies with poor workmanship on the part of
the plaster applicators especially the use of excessive amount of water to smooth/trowel the plaster.
Kim Skinner, from onBalance says: “It is excessive amount of water and re-troweling that leads to white
spotting”. As far as who is affected, well it is the industry as a whole (builders, plasterers, mgt. co’s, sales
stores, supply houses, etc.).
WHY: Well, this very large problem creates many subsequent problems. It can damage relationships
between professionals or even on the personal level with the client.
WHERE: This problem occurs nationwide and quite often.
WHEN: Spot etching first reeled its ugly head in the late 1960s and has progressively gotten worse up to
the present.
