Finish TradesCâu 216 / 700
Efflorescence (white crystalline deposits) appears on a masonry wall that is scheduled to be painted. What is the BEST way to handle it before coating?
a.Paint directly over it with a thick latex topcoat to hide it
b.Wet the wall thoroughly so the crystals dissolve into the surface
c.Dry-brush or otherwise remove the deposits and correct the moisture source before painting
d.Apply a glossy oil enamel to lock the crystals in place
Giải thích
Efflorescence is salt carried to the surface by moisture; it must be removed (dry brushing or masonry cleaner) and the underlying moisture problem addressed, or it will keep recurring and push paint off. Painting over it, wetting it, or sealing it with enamel does not stop the moisture and the coating will fail.
Luyện miễn phí toàn bộ 700 câu hỏi — không cần đăng ký.
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