Why does it matter?


One of the most common defects we discover when inspecting homes is dirty crawlspaces. It’s a dark, crowded space under your home, so isn’t it what a crawlspace is supposed to look like?

Actually, it’s a problem that is often overlooked.

Everything from moisture to radon gases can make it into the living space through spaces and gaps around penetrations made by plumbing, electrical wiring, heating ductwork and more! There are simple ways to help improve the quality of the air in your home and prolong the life of the structure.



How can it be made better?


Here is a list of goals when it comes to improving the crawlspace of your home:

  • Improved air quality
  • Improved energy efficiency
  • Elimination of pest harborage
  • Prolonging the life of the structure


What do we look for?

When conducting a home inspection, Building Code Pro will always attempt to make physical access to the crawlspace.  In some homes we encounter that the access point to the crawlspace is too small t

o safely access without an elevated risk of entrapment. If that is the case, we still find ways to capture images and information, but the small entrance is deemed a deficiency. If we can’t get in there, chances are pretty good no one else has been there for a long time. What’s lurking under there?!

When we do get access to the underfloor space, we like to see homes having a vapor barrier over the bare earth and insulation properly installed on the underside of the floor.



What is the best insulation to apply to the subfloor of my house?


If you are building from scratch, there is a lot of evidence to suggest that the best course of action is to insulate the entire crawlspace and treat it like conditioned space. This is costly and can lead to problems if attempted on an existing structure.

The lowest hanging fruit for the improvement of efficiency and indoor air quality is luckily also the cheapest improvement. Caulking! Put on a pair of overalls and get a good quality respirator and have at it! Identify all the gaps in the flooring, all penetrations (wiring, plumbing, and mechanical) and make sure that they are sealed properly.

The next next improvement on the “low hanging fruit” category is a vapor barrier. A vapor barrier is a non-permeable material that does not allow for vapors or moisture to pass. A good way to know for sure is to buy a vapor barrier that is designed to block radon. If it does that, it will also keep out moisture. Install it such that there is at least 6 inches of overlap at seams, and seal the seams with an approved adhesive. Also, make sure the vapor barrier extends up the sides of foundation walls WITHOUT covering any crawl space vents.



Where to place a vapor barrier varies from climate to climate, but in the North Bay of California, it is best to lay it directly on the soil.



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