Crawlspaces: Are They Right For Your New Home?

When you are planning to build a new home, you probably have thought a lot about the home's exterior, number of bathrooms, paint colors, and maybe even the type of shingles on the roof. However, perhaps the best place to begin is at the bottom: your new home's foundation. In many parts of the country, crawlspaces are the conventional choice; however, you need to consider why a crawlspace might be best for you, not necessarily for someone else. Here is what you should know about choosing to build your home with a crawlspace:

Crawlspaces--an introduction

If you aren't familiar with crawlspaces, the easiest way to visualize them as a very short basement. Typically no more than two to three feet high, crawlspaces provide a gap between the ground and your home's joists and subflooring. Concrete walls, resting upon sturdy concrete footings, line the perimeter of the crawlspace. In turn, your home's entire structure rests on top of the concrete walls. Some parts of the crawlspace can be built into the ground depending on the location of the home.

Many homes, particularly older ones, were constructed with crawlspaces that have dirt floors. In addition, some homes have ventilated crawlspaces, while others do not. Both of these factors are important in your decision-making process should you decide to build a home with a crawlspace, as you will see below.

Advantages and disadvantages of crawlspaces

When considering whether or not to build your home with a crawlspace, you need to know the pros and cons:


  • Accessibility - crawlspaces offer homeowners an advantage over slab foundations in that ductwork, plumbing, electrical and communication lines can be routed through this space. If a pipe develops a leak within or beneath a slab, then it will be very difficult and expensive to access the pipe. In addition, it is a fairly simple matter to add new wiring or plumbing in crawlspaces.
  • Storage - crawlspaces provide a homeowner additional room to store household items. Crawlspaces are particularly good for items that may need shelter, such as lawn care equipment, grills, lawn and patio furniture and other warm-weather items.
  • Shelter - a portion of a home's crawlspace can be converted into a storm shelter for persons that live in areas prone to severe weather.


  • Expense - crawlspaces typically add five to ten thousand dollars to the building costs of a new home as compared to slab construction.
  • Maintenance - a crawlspace will require periodic maintenance to protect your home. This includes inspections for pests, mold, and structural integrity as well as fixes for any damage caused by these problems.
  • Potential flooding - crawlspaces that are improperly built can be flooded by rising water, including moisture that lies beneath the surface of the soil. Flooding can create serious mold, pest or even structural problems, if it isn't promptly handled.

Good building practices for crawlspaces

If you decide to incorporate a crawlspace into your new home, you should be sure that your builder adheres to good building practices. Don't cut corners on your crawlspace; even though it is an area seldom seen by many homeowners, its importance to your home and its occupants should never be underestimated. Here is what you want in a crawlspace:

  • Use concrete to seal the ground - even though you can have a home built with an unfinished crawlspace, it is a bad idea to do so for these reasons:
    • Allows easy access for pests - rats, mice, termites, and carpenter ants are opportunistic pests that dig and will find their way into your crawlspace. Rodents chew on wiring and plumbing components and can spread disease, while termites and ants can damage joists and other critical load-bearing structures.
    • Permits radon gas to pass - in some parts of the country, radon gas can be a problematic. Radon gas is a naturally-occurring carcinogen capable of causing lung cancer; it enters homes through the soil and vulnerable construction points.

By sealing the ground with concrete, your home will much better protected from pests and radon gas. You should discuss options for thicknesses and other considerations with your contractor.

  • Create an airtight environment - the ventilation of crawlspaces has been controversial over time; both "ventilate" and "do not ventilate" have been strongly advocated, and home construction over the years reflects both positions. However, it is conclusive that the "do not ventilate" position is superior. Due to the fact that crawlspaces are cooler than the surrounding air during the summer, the warm, moist air that enters will cause condensation. As the condensation consistently keeps the pipes, insulation, and other structural components wet, it creates a perfect habitat for mold growth. Mold is dangerous due to the toxins it can release into your home's airflow, and some mold can also damage your wood by causing dry rot.