Opinions on $12,450 Crawlspace Encapsulation Quote. We just got a quote for $12,450 for our 1500 sf crawl space that includes 20 mil Clean Space liner over dirt and up block walls, 175 linear ft perimeter drainage piping, 2 sump pumps, and one dehumidifier...all installed in about 12 hours (1 1/2 day job). Does this seem like a fair/realistic quote?