Products & MaterialsQuestion 31 of 100
Why does a rough or porous surface (like bare masonry) reduce a paint's effective spread rate compared to the label value?
a.Rough surfaces repel paint entirely
b.The texture and absorption increase the actual surface area and soak up paint, so a gallon covers fewer square feet
c.Porous surfaces make paint cover more area
d.The label value already accounts for all textures
Explanation
Manufacturers' spread rates assume a smooth, sealed surface, but rough and porous substrates have more actual area and absorb paint, lowering coverage. Estimators reduce the assumed coverage for textured or unsealed surfaces. Priming a porous surface first reduces topcoat absorption.
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