A few years back, I came up with an idea for a book on how to buy older houses, in response to a publisher's listing on a website that advertised freelance opportunities for real estate writers.

With so many of these books on the market, however, I had to come up with an idea that was fresh and different, so I proposed turning old-house buying into a game, along the lines of Monopoly, but not so close that I'd be violating any copyright.

My idea was that a player wouldn't be allowed to buy a house, or reach Square One, unless he or she could first demonstrated the knowledge and drive that would allow the player to handle any challenge the house threw at him or her.

The proposal actually drew a somewhat favorable response from the acquisitions editor for the publisher. The problem was that someone else had gotten his proposal to the publisher first, a contract had been signed, and I was told to try again another day.

The approach, while unusual, wasn't realistic, because how could I prevent someone from doing what I had already done not once, but twice. In both cases, people warned me that I was getting in over my head. It took me a while to learn to swim, but not before I came close to drowning a few times.

Would I do it again? Not at 55, but if I were 30 years younger, I would, but I would be much smarter about it. I would spend two or three years educating myself, talking to real estate agents, builders and remodeling contractors, reading everything I could get my hands on, attending neighborhood meetings, talking to old-house owners.

Armed with buckets of knowledge, I'd start looking at houses for sale, not having to depend entirely on the opinions of professionals who, as it turns out, may be totally clueless.

Like the roofing contractor whose employees covered a downspout that handled water from my roof and two adjacent houses. When I complained that water was pouring into the next-door neighbor's mailbox during heavy rains, he came up and installed raised flashing at the corner of the roof, completely ignoring the fact that the downspout had been closed.

Flashing is important, but not as important as unblocking a downspout.

That's something I would have never been able to figure out from a book. You need to spend some time on a roof before you can begin to make sense of it, and what you should come away with is the realization that the health of the roof is critical to the health of the house.

If your roof is sick, making it well should be at the top of your list.

The signs of an ailing roof are fairly obvious when you know what to look for. If there are mismatched shingle or globs of roof cement, you know the roof has been repaired at some point. If the roof is lumpy, there are probably several layers of roofing material, and stripping off those extra layers and starting fresh is the way to go.

If the ridge of the roof looks less than straight, it is an indication that the building has or is settling. If there are interior cracks, it is good bet that the house has settled, and that you need a structural engineer to determine how severe the problem is.

If you can't afford to repair major structural problems, you shouldn't buy the house.

What is the roof made of? If the roof is made of asphalt shingles, curled or worn shingles are a sign that replacement is in order. Asphalt shingles tend to last about 25 years under normal weather conditions.

Wood shingles last about 30 years. If the edges of the shingles appear worn, it may be time to replace them.

Slate lasts 75 to 100 years. Slate roofs tend to be the most expensive, and fewer roofers are dealing with the material, so it might not be easy to replace the roof. Some roofing manufacturers have come up with asphalt shingles that look like slate, and that may be a viable option for you.

Some roofers patch slate with roofing cement. That is only a temporary fix. Once the slate begins cracking, it is time to replace it.

Metal roofs can last about 50 years, but they need to be regularly maintained. There are special paints made for metal roofs that should be applied regularly and following the paint manufacturer's recommendations.

Whatever your roof is made of, it needs to be maintained properly. Remember, leaks don't go away on their own. They just get worse.