My roof doesn’t leak, but I know it’s old. How do I know if it’s time for a new roof?
The first thing to consider is the age of the roof. Generally speaking, any roof installed before 1990 should be assessed by a professional. Back then most asphalt shingle roofs were completed with 15- or 20-year shingles and, quite simply, their time is up.
Warning Signs and What They Mean
- Black Stains: These are usually not stains at all. The tiny stone granules that make up the top protective layer of the shingle have worn off, exposing the asphalt mat material below.
- Lifting: Moisture problems in the attic space due to poor ventilation can slowly corrode the nails that fasten the shingles to the roof deck. As the nails deteriorate they become less resistant to expansion and contraction in the roof substrate, and slowly work their way back out, pushing up the shingle above.
- Thickening: If you have a roof composed of “3-tab” – non-architectural shingles – they should look thin, flat and uniform. If the shingle looks thick at the bottom edge it is because the asphalt and fiberglass mats are delaminating with age.
The edge of the shingle shouldn’t be much more than 1/16th of an inch thick. That way it is something you can occasionally detect with some certainty from the ground. The delaminating process leads to the eventual “curling” of the shingle material.
- Curling: Severely aged shingles will eventually reach the curl point. The shingle tabs will curl away from the sun at the edges, which forces the middle of the shingle up so the roof almost looks bubbly in spots. It also makes the spacing between the shingles look wider. Shingles in this condition are very brittle, and impact from any debris will break them. Eventually they will curl to the point of breaking on their own.
- Splitting or Cracking: This is usually an indicator of an old roof and too many layers of shingles. The Mass State Building Code allows for up to 2 layers of shingles on a roof. Part of the risk of multiple shingle layers is that when all of the layers have passed their prime, you are left with a thick mat of dried out material, so it loses some of its natural ability to flex with the movement of the structure.
- When the structure shifts, the shingles split and crack, sometimes through the whole length of the roof.
The best approach to your roof is to be practical. If you know it is old and you are going to have to replace it in a few years, you should strongly consider getting it done sooner rather than later. The cost to fix water damage and a new roof later will run a lot higher than a new roof now!