Hi all,
We have an almost 200 year old house in south Alabama.  It was built on brick piers and someone created an unvented crawl space with cmu block between the piers at some point a long while ago (although they left the porch crawl space open to the main house crawl space but we recently install a wall between the porch and main house crawl spaces to separate them).
The house has plaster walls and no insulation and original (or very old at least) doors/windows.  It has new ductless mini splits for heat/air that work well.
The house is not used often and the mini splits are not on when the house is unoccupied.  We have some slight mold issues in a central stairwell but the crawl space is dry and has no mold and no water problems, no rot, no termite activity.
We have no plans to insulate but we are working to airseal and improve air quality and solve critter problems in an attempt to improve basic comfort.
We cleaned the crawl space dirt floor and are planning to install a vapor barrier.  We got a reasonable quote to encapsulate (20 mil at floor, 12 mil at walls, foam at the rim joist (with space for termite inspection), dehumidifier, and new crawl space door.  I’m inclined to have the crawl encapsulated b/c I think it will help with the critter problems and generally improve the air quality/air seal and help with humidity issues which would increase comfort.
Do you all agree with my inclination?  Or are we potentially creating new problems?  Is encapsulation overkill?  Does the dehumidifier need to be connected to a ducted HVAC system to work well or should it be ducted to the outside or can it just stand alone.  Thoughts?
I read Martin Holladay’s article on building an unveneted crawl space and Allison Bailes article on 5 ways to deal with crawl space air but I’m worried that this house is a little different since it is used so little and the HVAC runs so little and it will likely never be properly insulated.
Thank you for any advice/info you can share.
Jennifer