Repairing A Shingle Roof - How To Replace Asphalt Roof Shingles
When the shingle roof needs repairing
So you had a windstorm last night and found a few shingles in your yard - looking up you see that you need to replace some of your old asphalt roof shingles (asphalt is the normal shingle type used on most homes).
Not to worry - replacing shingles on your roof, repairing a little wind or tree limb damage is not a huge deal and is well within the home handyman's capabilities. It requires only a few tools, found in most homeowners tool kits, and a little time.
Don't put off this minor task too long though - missing or damaged shingles can well end up turning a perfectly good roof into a major leaking roof repair, including repairs to damaged floors or ceilings below. It isn't worth it.
Tools for replacing roof shingles
A fairly wide, flat pry bar will be extremely useful. Something around 12 or 18 inches long and perhaps 2 inches wide. A razor knife (boxcutter) or other sharp knife may be necessary if the damaged shingle is on the edge of the roof.
A hammer will be necessary to drive new nails, along with a handful of roofing nails. These are not normal nails, but have an extra large head.
Depending on weather, some form of heat may be helpful as well. Existing shingles must be carefully bent out of the way, and cold shingles can and will snap under the pressure. A common bernzamatic torch would do the job if used carefully; in the photos used for this roof repair a large propane weed burner was planned for heating cold shingles. It turned out not to be necessary - temperatures were in the mid thirty degree F range and the shingles bent nicely. It was used as a final step, however, to help immediately seal new shingles down to old ones.
A ladder or other access will, of course, be necessary to get onto the roof.
Removing the damaged shingles
When shingles are blown off or damaged it is only the bottom half of a shingle that is typically damaged. What you see on a roof is only half of each shingle; the other half is tucked up and under the next higher shingle. In order to replace a shingle, then, the upper half must be removed first.
To do this, carefully insert the pry bar between the existing upper shingle still in good repair and the damaged one, working them apart. Take care here; it is quite easy to tear the shingle still in good repair, which will mean that it, too, must be replaced.
With the upper layer free, work the pry bar under the damaged shingle, prying upward until it is free of any nails or staples. Again, take considerable care not to damage good shingles during the process.
Slide whatever is left of the damaged shingle out. Drive protruding nails or staples into the roof until they are flush; you don't want them holding the new shingle higher than it should be. These nails or staples could be removed rather than driving them flat; some of the shingles replaced on this job were up under the ridge cap and difficult to reach with a hammer and they were simply removed.
Removing damaged roof shingles
Replacing the damaged roof shingle
With the area prepared, slide the new shingle into place. Line up the bottom of the shingle with adjacent shingles to each side. The new shingle will not quite fill the gap between the shingles on either side; equalize the gaps between shingles side to side. You may find that the shingle needs lifted slightly to slide over staples, nails or the next shingle; slide a hand up under it and carefully lift slightly.
Very carefully roll up the shingle just above the replacement until the tar line is well exposed as this is where the nails should be driven in. Drive 2 nails on each tab, or 6 nails per shingle. The nails, if driven through that tar line, will hold both the new shingle and the one beneath it.
Allow the upper, rolled up, shingle to relax back into place, helping with a little hand pressure. As shown in the photo, it is a good idea if possible to apply a little heat to help melt the tar and seal the new shingle to the older existing one underneath it.
The job shown needed replacement of 4 shingles, plus one that was damaged in the process of "unsticking" it from the broken one, for a total of 5 shingles. It took about an hour to do the task; a small amount of effort to protect the investment of your home.
© 2011 Dan Harmon
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