Crawl Spaces

Homes with crawl spaces are certainly among the least favourite for Home Inspectors. Under these floors though we find water supply pipes, drains, water shut offs, electrical, heating and ventilation, as well as much of the visible structure of the home. Inspecting crawl spaces is important in a home inspection to give clients a good report on a home.


What is a Crawl Space?

Our wood framed homes need to be kept above the soil in order to prevent ground water and insects from damaging our homes. To accomplish this, we typically pour concrete foundations which have walls that rise above the soil grade level which the wood home then sits on. A crawl space is the free area under the home where it has been lifted above the soil grade. It can also be defined as a short basement as typically when costs, ground water levels, and soil conditions allow, the foundation and excavated area under the home would be full story deep creating a full sized basement.


Types of Crawl Spaces

  • Dirt Crawl Space - Many older homes had crawl spaces which were unfinished with the home sitting above dirt while the homes walls sat on concrete or block foundations. Insulation may have been placed under the floor boards. We have learning in building sciences since this was common that the ground will release large amounts of humidity into both the crawl space and the home promoting rot and mold growth. Water could transfer into the home by condensing on warm surfaces or penetrate the home as vapour. Air vents added to the crawl space walls may not be as useful as desired as when heat rises in homes, it can pull cool air in these vents which only encourages the moist air in the crawl space to rise into the home. Dirt crawl spaces are also very uncomfortable to be in so they are inspected very infrequently potentially leaving major home issues unchecked. While dirt crawl spaces can be remediated into conditioned spaces, this is an expensive process and damage to the home may already exist. Dirt crawl spaces should be avoided by home buyers.
  • Conditioned/Encapsulated Crawl Spaces - An encapsulated crawl space is treated more like an interior area of the home. The area is ‘conditioned’ meaning heat and ventilation from the main home is circulated through the space with insulation in the floor and walls. The dirt floor has been replaced with moisture barriers, insulation, and concrete or occasionally moisture barriers, insulation, and a ballast like gravel. Having conditioned air circulating through the crawl space prevents condensation and vapour from causing rot and mold issues in the home. The moisture barriers and finish also keep the area dry and make it accessible for regular access and inspection. The biggest issue for home inspectors in conditioned crawl spaces is visible access as home owners often use this space for storage (which is fine).


What Do Home Inspectors Look for in Crawl Spaces?

Crawl spaces are excellent for visibility to many of the main house systems. Wiring, plumbing, gas lines, and structure are all visible for evaluation. Crawl spaces also often have main water turn offs and waste clean outs. Home inspectors in earthquake zones can also look for seismic shear walls or other seismic upgrades.


While a good home inspection requires inspection of these areas in the crawl space, it is up to the home inspector to determine if it is safe to enter the area. Standing water is very dangerous as it may contain contaminants, bacteria, or even electrical charges. Exposed nails and screws can cause personal injuries. Low pipes or wires may be damaged by inspectors moving past. There is also a question of personal safety if something went wrong while the inspector was in the crawl space, could they get out safely. At Solid State Inspections, we require an access to be at least 24” x 24” and will only fully traverse a crawl space in areas where there is at least 3 feet of clearance. These standards are set for inspector safety in case we need to be rescued by emergency personnel.


How Should Crawl Spaces Effect Home Buyers?

Crawl spaces are one of the common foundation types for homes and when properly built are excellent to own. Dirt crawl spaces should be avoided in favor of fully encapsulated crawl spaces. Crawl spaces with very low clearances or small accesses should also be avoided as this confinement will make regular access and inspection rare which could result in damaging system failures being unnoticed for long periods of time. If you live in an earthquake zone, crawl spaces are also an excellent location to determine if your homes resistance to seismic events. While a home inspector cannot tell you how large an event the home can withstand, they should be able to identify if any attempts have been made to make the home resistant to seismic damage.


Final Thoughts

If you own a home with a crawl space and have not been in it in years or are looking at buying a home with a crawl space, have your local home inspector give you an assessment of the structure and mechanicals of this space. Spending a little money now on regular maintenance could save you thousands of dollars in the future and will help you know your home is safe and solid.


By James Bell - Owner/Operator of Solid State Inspections Inc.