A crawlspace is a shallow and uninhabitable area, usually between the soil and the first floor of the home. Crawlspaces usually provide access to the electrical, plumbing and heating, ventilation and air conditioning (HVAC) systems located below the first floor. Crawlspaces are an essential part of the home inspection process. We regularly find WDO issues, plumbing leaks, water intrusion, and structural issues. Frankly, crawlspace inspections are not fun due to awkward entrances, tight spaces, airborne inhalants, mold, mice, rats, snakes, hazardous dust and spiders like the Hobo Spider, Brown Recluse and Black Widow.
The following general guidelines are required in new homes:
- Minimum access opening is 18 inches by 24 inches.
- Minimum access opening if mechanical equipment (i.e. if an HVAC system is located in the crawlspace) is 30 inches by 30 inches.
- Minimum clearance between the soil and joists is 18 inches and 12 inches between the soil and beams.
- Minimum ventilation every 150 square feet of floor space, requires a one square foot ventilation opening.
Crawlspaces are common problem areas, usually due to poor design and/or construction. Fortunately, in many cases simple corrective measures can greatly improve the condition of the crawlspace. Some common crawlspace issues are:
- Inadequate ventilation and/or insulation.
- Rotted wood components or Mold due to condensation.
- Lack of moisture barrier on ground.
- Inadequate clearance between wood components and the ground.
- Wet crawlspace.
- Inadequate framing and support.
The best way to protect against mould, mildew, and wood rot in a crawlspace is to ensure it is well ventilated and dry.