Halloween is around the corner, so perhaps this is a good time for a hair-raising statistic:

According to researchers at Marshall & Swift/Boeckh, 64% of homes in America are underinsured by an average of 27%. Yikes!

The importance of this problem becomes fairly clear when you think about the devastation experienced recently by many homeowners in Florida. You simply can't afford to be underinsured. If your home is destroyed and you don't recoup enough to rebuild or replace it, you're in deep doo-doo.

The problem is actually an ironic one, since the insurance industry only stands to gain by having people properly insured. Higher coverage means higher premiums, after all.

So how did it come to this? Who or what is to blame for this sorry state of affairs? Here are some candidates:

  • Homeowners themselves. Odds are, you know what your home is worth, roughly speaking. Are you covered for that amount? If you've added on a room or have had some extensive remodeling done, did you upgrade your insurance to cover the increased value?

  • Building material costs. The prices of wood, steel, and other commodities have been skyrocketing in the last year or so. If you're a do-it-yourselfer who frequents places such as Home Depot (NYSE:HD) or Lowe's (NYSE:LOW), you've likely noticed some significant price changes. These mean that old estimates of how much it would cost to rebuild your home may no longer be accurate.

  • The insurance industry. Not all agents know how to properly value a home. And some, in the interest of getting your business, may even knowingly lowball your coverage.

Ray Martin at CBSMarketWatch.com notes that "Every homeowner needs to know that the old-fashioned 'guaranteed replacement coverage' that provided homeowners peace of mind that their home would be replaced regardless of the rebuilding costs is quickly becoming a thing of the past. Most homeowners policies sold today are called 'extended replacement coverage' or 'specified additional amount of insurance,' which only provides coverage up to the dwelling limits specified in the policy plus an additional amount of up to 20 to 30% -- and not a penny more."

Learn more about insurance in our Insurance Center -- it's not the most exciting topic, but you can save yourself and your loved ones a lot of trouble and money by making sure you have the coverages you need. See what advice and experiences Fools are sharing on our Insurance discussion board, too -- we're offering a free trial of all our boards right now.

And learn more about home issues in our Building/Maintaining a Home discussion board, where many Fools share their experiences. Also, check out our Home Center, which features tips on buying or refinancing a home, and special mortgage rates, too.

Longtime Fool contributor Selena Maranjian owns shares of Home Depot.