There are some clear signs that your roof needs full replacement. In some cases, repair will not suffice. You would end up spending more, over time, to repair a roof than simply to cut your losses and buy a full new roof.
Here are eight such signs:
You have moss growth
Moss keeps moisture on the surface of the roof. This can damage the granules of the shingles, particularly if you live in a less temperate climate, where freezing and thawing are natural parts of your existence. You can brush away the moss, which helps with its cheap and damaged-looking appearance, but it will just grow back.
The growth of moss can cause lasting damage to your whole roof, and it is very difficult to get rid of.
You have dark streaks
These dark streaks are usually a sign of airborne algae. While not as serious as moss, when it comes to the long-term life of your roof, you none the less want to get rid of these streaks.
To get rid of these streaks, you can spray a half-half bleach-and-water blend onto your roof. Be very careful, though, to protect the landscaping below from the bleach as it flows off of your roof and gutters. Also, use a low-volume hose to spray your roof, as otherwise you will knock off the little granules that are protecting your shingles.
Your roof would be old enough to drink alcohol
Roofs seldom last more than 20 years. Newer shingles are produced for longer lives and greater ability to endure harsh weather and rough seasons, but nonetheless your roof may just be suffering from the effects of old age. If your roof does not have sufficient ventilation, then your shingles are likely in trouble anyhow.
Your shingles are cracked
Those cracks mean your shingles have outlived their usefulness. The fact that fissures are breaking out across the shingles means that moisture can get into the interior your roof. This could be causing your attic to rot and mildew. Those cracks indicate a serious health hazard.
Your shingles are balding
Those bald spots you might see on your shingles mean that granules are falling off. Those little granules are there as a protective measure, and they are helping your shingles survive. If the granules go, then the shingles are exposed to all sorts of possible deterioration.
The rest of the neighborhood is changing
The houses in your neighborhood were likely built around the same time. If your neighbors are getting new roofs, then it is a solid sign that your roof is ready for replacement.
The edges are curling up
As shingles age, their edges curl up. Also, the shingle taps can round off, and start pulling up from the surface of the roof. If those edges are curling, then your shingles are separating from the roof, and if that is happening, it is time for a new roof.
If your roof is sagging, then the roof as a whole could be approaching collapse. You do not want to have a giant hole in your roof — but that is what that droop could be showing you. It means moisture could be collecting, and the boards that are the structural basis of your roof’s infrastructure are rotting away.