It’s that time in your home’s life that fortunately only comes around once every 20 to 25 years or so…roof replacement time! Or maybe it’s time to tackle a big task with a shorter life span, like painting the house.

Either way, for projects at this scale you wisely skip the DIY approach and instead find yourself in the market for a contractor.

Let’s take roof replacement as an example. The roofer contractor you’ve zeroed in on came with a great recommendation from a friend, supported by an attractive portfolio and sharp online presence. Is he insured? Of course! You sign a contract, pick out the shingles and are ready to go, right? Not so fast.

Even though your contractor has proof of insurance and you carry homeowner’s insurance, you could still face a coverage gap and corresponding risk, plus the potential of higher premiums should you have to file a claim on your policy because of a peril related to your roofing project.

To close the gap and eliminate all potential pitfalls, make sure your roofer at the very least adds you as an “additional insured” to his general liability policy before you sign the contract. It’s easy and cost efficient for him to do so and the right move for both of you.

When you’re added as an additional insured, it means the insurance carrier underwriting the policy extends its coverage to you for a certain term. There are many reasons for why this can come in quite handy. Consider these two examples:

Your contractor is in your attic checking the roof sheeting. It’s dark and he accidently falls through a hole in the floor and gets hurt. If you are named as an additional insured, you’re protected against a lawsuit because his policy coverage for accidents such as this now applies to you as well. However, as part of the contract between you and the roofer, it’s important to include a “waiver of subrogation” clause, which would prevent the contractor’s insurer from pursuing your insurance company (or you) for costs related to any worker’s compensation claim that may be filed. No claims filed against your policy means your premiums stay in check.

Another important clause to your additional insured policy is “completed operations” coverage, which essentially means the coverage survives the end of the job. Let’s suppose the roof is complete and the contractor has cleaned up and gone on to his next job. The following day, a UPS driver is walking up your driveway to deliver a package and steps on an overlooked roofing nail, causing an injury. The driver sues, but since this was the fault of the roofing company AND you had additional insured with completed operations coverage, the roofer’s insurance carrier is still yours in this case and will handle the litigation and any payout. You are liability free and again, your homeowner’s insurance stays untouched.

Additional insured clauses are an easy way to protect yourself when contractors are working on your home. They are commonly used and take almost no time to secure, so make sure you insist on one for your next home improvement project.