How to Re-shingle a Roof
The most important being SAFETY FIRST!
Always let someone know when you go up on the roof to repair things or have a helper up there with you. Make sure that you have a sturdy ladder that is secured at the top as well as the bottom before climbing up. Do not wear loose clothing, and do wear heavy duty rubber sole shoes with non slip grip on them. Put up extra footing supports such as 2x4's to prevent slipping as well. Make sure that the tools you will be using are in reach, and make sure to clear the roof of debris and unused objects.
Steps to re-shingling a roof
1. Lay down the roofing felt; make sure the felt overlaps the preceding course by at least 2' to provide good weatherproofing protection. Start at the edge of the eaves and extend up to the roof ridge.
2. Mark the vertical center of the roof across the whole roof with a chalk line. Do this with a chalk line. Then find the center of the roof along the bottom edge of the roof and make a chalk line to install a starter strip. To make a starter strip cut the tabs off the shingles and use the shingles to form a starter strip. This strip should project out over the eaves and the gable end by about 5/8".
3. Again locate the exact center of the roof on the starter strip and mark it with a horizontal chalk line. Make horizontal chalk line all the way up the roof every five inches. Make vertical chalk lines all the way across the roof every six inches.
4. Center the first shingle on the chalk line directly on top of the starter strip and nail it into position. Use four nails in each shingle. Do not drive them in at an angle, always be straight on. The nails should be 5 5/8" up from the bottom of the shingle.
5. Continue to lay shingles making sure the top edge is with the horizontal chalk line and the ends are with the vertical chalk lines to create the proper six inch offset. Do this for the entire roof.
6. When you get to ridges or the ends of the roof trim the shingles. The shingles around the ridge should be cut to 12x12inches. Center each ridge-cap shingle over the ridge and nail it down with two nails.
Then you are finally done. This is a big job so make sure that the weather will be nice for a few days in a row while you do this because it will take more than one day for total re-shingling.