We own a house on a steep hillside in Southern California with a vented, dirt crawlspace. We noticed efflorescence on the foundation walls in our vented dirt floor crawlspace, but there’s no mold present. Living areas directly over crawlspace have had high humidity, so we ended installing footing drains around most of house, waterproofing exterior of foundation walls, concrete swales, ensuring roof rainwater drains properly, etc... After all this work, we didn’t notice much difference in crawlspace humidity, so my final step was to install a 20 mil vapor barrier extending about 12 inches up foundation walls. Since doing this, I’ve noticed increased dampness on foundation walls with significantly more efflorescence where vapor barrier plastic ends, which I attribute to the fact that there will naturally be more dampness under a vapor barrier. Should I have skipped the vapor barrier and increased crawlspace ventilation instead? I’m concerned about foundation integrity with the degree of efflorescence I’m seeing, but I’m pleased that the vapor barrier has completely fixed our humidity issues inside the home. Thanks for any advice.