One layer of shingles is acceptable, two layers are not. A single layer of shingles will look better, last longer, and will not put any unnecessary extra weight on the roof.
One way to combat that issue is to run heating cables inside the gutters and downspouts. Make sure to turn the cables on during snowy, freezing weather so that it will help keep them from freezing and icing over.
There are several clues with the biggest clue being age. If your roof is more than 20 years old, there is a good chance that it is due for replacement. Younger roofs can also fail so it is always a good idea to have your roof inspected once a year. The most common thing to look for is shingles that are lifting, cracked, missing, or curling at the edges.
When you see that the nails in the attic have frosty tips on them that means that there is warm, moist air from inside your house seeping into the attic, and moisture is condensing and freezing on the cold steel nails. You should do something to correct the air seeping issue because it can reduce the effectiveness of your insulation and encourage mold growth.
The dark streaks are a type of algae that lives off the minerals in some types of roof shingles. Algeo thrives most in moisture. Algae do not damage your roof it just does not look the nicest. You can get rid of it using a pump sprayer to wet the roof down with a mix of one part bleach to two parts water.
-Roof Leaks- This is one of the most common roof issues that homeowners face.
- Asphalt Shingles. This is the most common residential roofing material used in the United States. They are economical and easy to install.
-Metal Roofing- both Corrugated and Standing Seam
-Rubber Roofing- Used mostly on flat roofs.
-Wood Shakes & Cedar Shingles
-Ceramic Roof Tiles
A roof valley is formed where two roof slopes meet. Water collects in a valley to flow off the roof. Your choice of valley installation method is critical because when improperly installed, valleys are at risk of serious leaks.
Roof flashing is a flat thin material used to prevent water from entering the openings and cracks of a roof. It is placed underneath the shingles of your roof and redirects the water to another location. Roof flashing is made from metals such as copper, aluminum, stainless steel and galvanized steel.
- Wood Shakes & Shingles: 15-20 Years
-Asphalt Shingles: 10-30 Years
-Slate: 50+ Years
-Tile & Concrete: 50+Years
-Build-Up Roofs: 25-30 Years
-Single-Ply: 30+ Years
Moss holds moisture against the shingles and will ultimately shorten their life span. If your shingles are in good shape, you can make a 50-50 mixture of bleach and water and spray it onto the roof, wait 15 minutes after you have saturated it, and then rinse it clean. You should complete this process from the ground because wetting the moss-covered roof will create a very slippery roof surface. In the event that your shingles are not in the best condition, it would be best to have the roof replaced.
Felt paper is typically used in most roofing as a release between the two materials, wood, and asphalt. It also provided some lightweight protection in the event that a shingle would blow off.