Let’s suppose you’re buying a house. Your home inspector says the roof’s shingles need to be replaced. However, the seller says this isn’t necessary because the roof doesn’t leak and never has. He says he’s not replacing shingles as long as the roof still sheds water. Who’s right? What should be done?

First, there are two main techniques for evaluating a roof. One is to objectively determine the physical condition of the material of the roof. The other is to find a subjective answer to whether the roof actually leaks.

Your inspector will do what good professional roofing contractors do and check the physical condition of the roof. If the roof is deteriorating and decomposing, your inspector will routinely recommend replacement, regardless of whether there is evidence of leakage.

The more pragmatic approach of asking whether the roof leaks doesn’t really deal with the issue. To assume the roof won’t leak now or in the future is wishful thinking. It demonstrates misguided hope and an unwillingness to face the fact that costly repairs or replacement are in order. It’s not a good idea to rely on old shingles just because they’ve done their job to this point.

The real question is whether an old roof should stay in place until water damage in the home makes replacement an absolute must. Those warning signs of wear shouldn’t be ignored. Doing so exposes walls, ceilings, and furniture to needless water damage.

In case this seems like strong medicine, think of it this way. You wouldn’t want your car mechanic to overlook brake problems just because you’re still able to stop your car. If that were the case, an accident with potentially serious or fatal consequences would happen sooner or later.

Imagine going to the doctor and being told you have high blood pressure. You didn’t know there was a problem, but your doctor explains your condition and prescribes medication and gives you guidelines to minimize the risk of heart attack or stroke later. It’s the same kind of situation when a home inspector notes the condition of an older or damaged roof. Heeding warning signs and taking steps to correct the problem now prevents trouble later.

What should you do when you and the seller still can’t agree on what to do about the roof? A licensed roofing contractor should be called in to professionally and objectively evaluate the roof’s condition. Final resolution of the problem should be based on the following considerations:

* The true condition of the roof

* The effect of a deteriorated roof on the value of the property

* The motivation of the seller to complete the sale

Remember this. Even if replacing the roof is called for, the seller is still not obligated to replace it. Whether the roof gets replaced before the sale depends on the terms of the purchase contract.

If the seller remains adamant about not repairing or replacing the roof, you may need to seriously reconsider whether you’ll purchase the home. Perhaps the seller’s attitude and actions indicate other unforeseen problems with the home after it’s been sold. This is a significant example of how crucial a home inspector’s evaluation is to your home buying decision.