Removing and replacing one or two asphalt shingles can be done easier than you think with following some proper safety precautions and using these step by step instructions.
First, any time you're getting up on the roof you need to practice roof safety.
Wear protective eyewear, heavy-duty gloves, and gripping boots appropriate for walking on sloped roofs. Preferably, you may also need to install roof jacks to have something to stand on, and harnesses to protect yourself. And never do roof work alone.
How you access the roof will depend upon the roof itself and the location of the damage.
Always use a secure, sturdy ladder when climbing up on the roof, and have a helper secure it at the base. When walking on the roof, always walk slowly and secure your footing before taking another step.
If you're just trying to assess the damage and replace a few damaged shingles, it might seem like overkill to install roof jacks and harnesses, but depending on the complexity and the height of your roof, it might be the safest option. Roof work isn't something to rush.
Assess The Damage
Find the damaged area of shingles and determine how many new shingles you'll need and the extent of the damage underneath. Look at the corners on the shingles surrounding the affected area.
Check the area for damage to the moisture barrier or flashing and signs of seepage.
If the surrounding shingles aren't doing the work of keeping moisture out, you'll need to replace everything in the general area around the damaged shingle(s).
In some cases, it might be better to replace all the shingles from a roof in bad need of repairs instead of spot repairing. If the shingles in the area surrounding the damage are old, brittle, and dry, it’s probably not worth taking the care to re-secure them to the roof.
Cracked or split shingles may be repaired without removing them,(only a temporary fix until new shingles can be installed) provided they're still in relatively good condition.
Removing shingles in cooler weather
Asphalt and asphalt sealant will heat up and become softer in hot weather, making it moldable and more difficult to remove. It's a lot easier to remove shingles that are cooled down and slightly more rigid than very flexible ones, so try to do the work of removing them first thing in the morning, before the sun has heated upon them all day.
Wetting the shingles to cool them down before removal, if you must work in the heat, is also an option, but now that is introducing a safety concern.
Loosen the adhesive under the tabs two rows above the damage
Removing shingles on the roof is usually done with a roofing crow bar, a hay fork , or rake-sized scraper. The trick is getting under and carefully prying up shingles, separating the adhesive and revealing the nails of the shingles underneath.
A good rule of thumb is to remove at least five tabs in the second row above the damaged "3-tab" shingle. Pull up enough shingles to reveal the nails of all the damaged shingles that need removed below.
The end seams should be lined-up about a foot off to one side of the damaged one. In other words, you'll want to make sure that you pull off shingles in a radius around the damaged portion, to make sure you get everything.
Loosen the exposed nails
Slide your flat pry-bar under the shingles around the damaged portion. Work around the nail, pulling it up. Carefully lift each surrounding tab about 45 to 60 degrees. Go very slowly, but pry firmly, and try not to crack or break them. If the surrounding shingles are in good shape, you can reattach them when you're finished replacing the damaged shingles, saving you money and effort.
Work your way progressively closer to the damage. Lift the tabs in the first row above the damaged shingle and withdraw the loosened nails from that shingle with the pry-bar by using the same process.
Loosen and remove the damaged shingles
Loosen the adhesive underneath the tabs of the damaged shingle, then pull them free and discard. If the shingles are severely damaged, don't try to salvage them. Just remove them and replace them with new shingles of a similar style to the rest of the shingles on the roof.
Continue removing the damaged shingles until you've cleared out the shingles that will need replaced. It'll be easier to remove everything before you replacing them.
To replace shingles, you'll obviously need new shingles to replace the ones you remove and the materials necessary to secure. To complete the job properly, you'll need:
Replacement shingles. Buy more than you'll need at the roofing distributor. You should be able to count up how many damaged shingles will need replacement and buy accordingly. It's good to have replacements on hand.
Shingle cement or adhesive. Some shingles come with adhesive strips pre-installed, making this unnecessary. If you buy Non-factory applied sealant shingles (these are rare), though, you might need to purchase additional adhesive to secure them to the roof before nailing them. It's a good idea to buy it to secure other loose shingles anyway.
Roofing nails. To secure them, you'll need roofing nails, which are heavy-duty, and about two or three inches long.
Install the new shingle
Place a new shingle in the same position as the shingle you removed. Follow shingle nailing instructions that you purchase, or use the other shingles on the roof as a guide.
Reseal under edges of all three shingles
Lift each tab slightly on the shingles as you install them, and apply a 1" (2.5 cm) diameter spot of shingle cement under each tab or every 12 inches or so. Press edges down into the cement firmly and secure the shingle into place. Continue installing shingles and securing them with adhesive accordingly, until you've installed all the damaged shingles along the row.
After you've finished the damage portion, you can start working your way back up the roof, renailing the loose shingles into place, as long as they're in good shape, and using the adhesive to secure them back onto the roof.
Secure other loose & unsealed shingles while you're at it
While you're up there working, it's a good idea to keep an eye out for other areas that look like they may become problematic in the future. Keep an eye out for other badly weathered or unsealed shingles that might be further problems later. Using your adhesive, lift the tabs gently and re-secure them.
A Step by Step Video
We know all of this is a lot to take in and remember if you never removed shingle before, so we attached an excellent video by Gary Jones that is available on youtube and link below.
Watch it several times and performing this small job will be a lot easier.