What is the need for belly board???

[msmodular]

Why is belly board necessary? My parents home is a site built post and beam home that was built in the 1950's and there is no belly board under it; it doesn't have any poly on the ground either. The only homes I know that have belly board are manufactured homes and manufacuterd modular homes (like mine). There are thousands of post and beam houses that have nothing between the floor and the soil that have held up and remain plumb for decades with no problems. Belly board adds to the headache of finding responsible repair people who will re-seal it and in finding people who want to begin the job at all.

[David Oxhandler]

The belly board has nothing to do with the home being plumb and level.  It serves to support the insulation that is under the floor.  This  makes the home much more energy efficient than one with nothing between the floor and the soil,  Also  the plumbing that runs thru the floors is on the warm side of the insulation to help protect from freezing in winter. The BB also is a vapor barrier that prevents moisture from settling in the floor space and becoming mold.   It is good that you recognize that it takes a responsible contractor to restore your home back to original condition after any repairs.  Yes it can be a headache finding  one but you wouldn't want to settle for one that was less than responsible.   Removing and replacing Belly bd is not a difficult task if you can get under the home comfortably If you do replace the insulation you remove with brand new rolled insulation. Once you replace any insulation that any have fallen out  you can purchase rolled vapor barrier material (Bottom Board) install it from below, stapling it to the bottom of the floor joist so it supports the insulation. You can find bottom board products at The Mobile Home Parts Store For details about installing insulation and important safety tips see How to Install Fiberglass Insulation and Crawl Space Insulation, from the U.S. Dept of Energy.