I love a cottage porch with a pretty sky blue painted ceiling. I actually just learned recently the true purpose of the Haint blue ceiling from reading a post by Laura Casey Interiors. Here is a quote from her post:
"According to Louisiana legend, a “haint” is a spirit or a ghost. The blue paint represents water through which evil spirits cannot pass. Some say a blue porch ceiling helps extend daylight as dusk begins to fall, and others still believe that it helps keep bugs away. When the tradition began, bugs were deterred by the lye in paint – today many theorize that insects do not nest on blue ceilings because they think the blue paint is the sky."
I have always admired a blue porch ceiling. The blue ceiling gives a little unexpected pop of color and adds authenticity to a porch. I first noticed it on the porch ceilings of the historic houses in Charleson, South Carolina and always thought it was just a tradition that started in Charleston. I should have known there was a good story behind the trend.