Step three: Get building permits
Some jobs require building permits, particularly if the structure of your home will be changed. In these instances, work must adhere to building codes. Your city or county government can tell you whether your project is under this category. If so, have the contractor apply for the permits. Once the job is done, a building inspector will inspect the work, says Carolyn Gorman, a vice president with the Insurance Information Institute.

If the work fails the inspection, the contractor is liable and has to make adjustments. Incompetent builders can have a tremendous effect on your home's coverage. If you add a room to your home and it does not meet building codes, your insurer could refuse to cover it.

Step four: Estimate the project's worth
Every home improvement project need not warrant a change to your home insurance policy. If you buy a new refrigerator, change one or two appliances or upgrade one of the bathrooms, there's probably no need to make revisions. "But any time you're investing more than $25,000 back into the value of your home, your insurance company should really be on notice of that change," says Standring. If unsure, err on the side of caution and check with your agent anyway.

Step five: Review your policy
Once the project is complete, your insurer can help you determine how much value the work has added. This information is crucial: You want the homeowners policy to reflect the new, upgraded value of your home. Say your home is insured for $200,000. Add an expensive addition but fail to revise the policy, and it's like the work didn't happen. If your house burns down, what proof do you have of any improvement work?

"When it's time to rebuild, your insurer is not going to give you any more than $200,000 because that is the policy limit," says Gorman. There is an exception to this rule. If you have an extended replacement cost policy, it pays a certain percentage -- generally 20 percent to 25 percent -- over the limit to rebuild your house. While such a policy would cover minor renovations, you will no longer be adequately covered if you increase the value of your home by more than 25 percent through the improvements you've made.