Asphalt shingles although flexible in warm weather often incur damage during cold winter months during snow or rain storms. The reason for this is because the tar in the shingle hardens and the fiberglass backing becomes ridged and cracks.
If you are watchful of your roof early fall inspections can help you find any loose ends of shingles which can be reattached with roofing cement or pure silicone. However once the shingle has cracked and broken trying to piece it back together is some what of a losing game.
Probably the most difficult part about replacing shingles on a roof that is more then 3 or 4 years old is finding a batch of new shingles that will match your roof. If you thought ahead you asked your roofer to save you a pack of matching shingles that were left over when the job was performed. If not then you should take a piece of shingle with you to your supply center for color matching when you pick up your replacement shingles.
To replace the shingle you only need a few simple tools.
A long flat prybar not a crow bar for reaching under the shingle to remove the nails.
4 inch putty knife
A heavy duty utility knife
Small box of 2 inch roofing nails
Caulk Gun and Tube of Roofing Cement
A ladder to get up on the roof
The most important thing about this job is safety. If you have not been up on your roof for a while you are likely to feel a little uneasy however by moving slowly and only caring tools in one hand while the other hand is free to grip the roof surface you should feel a little more at ease.
It is also important to wear grippy sneakers and clothing that is not bulky. If it is a little chilly out it is better to work without your jacket then to struggle on the roof surface.
If you are working on a extremely pitched roof surface you can use a ladder attachment to hook a second extension ladder over the roof peak and use a safety harness with a line attached with specifically rated anchor mounts.
Removing the old shingle
Shingles are installed with a 50% overlap this means when remove the old damaged shingle you will need to remove the nails that hold it to the roof and the nails that hold the shingle above it to the roof.
The first thing you want to do is use your putty knife to break the bead of asphalt sealer that holds the front edge of the broken shingle to the roof. Make sure you do not damage the surface of the good shingle below it.
Now do the same thing to the tabs on the shingles above the damaged one you are removing.
To remove the nails on the broken shingle force your flat prybar up under the shingle to pry out the nails. Nails are located at the edges about one inch in and above each notch of the shingle tab.
At this point you may be able to remove the damaged shingle. If not you will need to force your prybar up under the shingles above the one you are removing and remove any nails holding the bad shingle in.
Once the bad shingle is loose you can remove it and match it to your new replacement shingle. The shingles should be the same size unless the one you are replacing was cut when it was installed.
If the new shingle needs to be cut lay the old shingle over the new one and cut lightly through the back of the shingle about half way. Do not penetrate any shingles on your roof you only need to cut into it half way. Then you can bend the shingle at your cut line and it should break on the line pretty easily. If not then use your utility knife to complete the job.
Installing the new shingle
When you nail in your new shingle you want to start with the lowest one first and work your way up the roof.
Insert the shingle and line it up with the edges of its neighbors then place a nail above each tab notch and one on each end.
Now reinstall the nails that you had to remove from the shingles above.
To complete your work you want to place a 1/4 inch bead of roofing cement under any tab that is loose.
Replacing shingles should be performed when the weather is above 60F but if necessary the work can be performed at any time as long as you take proper safety precautions.
If you do not feel comfortable working on your roof call a professional. Never take chances on a snowy or icy roof. Professionals with experience working in these conditions every day can perform the work safely.