The toughest part of roof replacement is stripping off the old shingles and loading new bundles of shingles. As I’ve mentioned in a previous post, old shingles and roofing material must be stripped before installing the new materials. An asphalt shingle roof must be installed on a clean flat surface to help maintain endurance. Every old nail must be nailed down flat or pulled (I prefer pulled). Every gap must be covered over and every lump on the roof’s decking must be flattened out. When inspecting your old roof, note that anywhere you have a lump in the shingles, the shingle granules will have been displaced. For this reason, the old roof must be stripped. Don’t let anyone tell you otherwise.
Before you begin to strip the old shingles, make sure your debris collection bin is close enough to the house to be able to throw the old material into it easily. Place tarps on each side of the bin to catch material that always seems to miss. Also, place tarps below the bottom eaves to collect debris that will inevitably fall, particularly on flower beds and lawns, which are not easy to sweep. A lot of nails will fall onto the lawn and you won’t be able to find them all without a tarp to catch them. You can buy a magnetic nail catcher. They are fairly inexpensive, but they don’t do flower beds well.
Next, get your ladder set up securely. Anchor it down securely on both the top and the bottom. Make sure there at least 3 rungs above the edge of the roof before you secure it. You don’t want to have to bend over the edge of the roof to get onto the ladder from the top.
Once you’re on the roof, place your fall protection anchors about a foot down from the ridge opposite the side of the roof you intend to start on. Secure the anchors with at least six 3” screws into solid wood, which usually means a roof truss. Once your fall protection is installed and everyone is secure, you can start stripping the old shingles. Strip the side of the roof farthest away from the garbage bin first.
As in all things, there is a hard way to do things and there is an easy way to do things. First timers usually begin ripping shingles without much strategy. But a little strategy can make the task much simpler and quicker.
Start by tearing off the cap along the ridge. Take your ripping tool and lift all the nails before you lift the cap. They’ll be somewhat glued together and are easy to pick up in groups of 5 or 6, stacking them as you go along and throwing them into the bin. Avoid throwing them around and picking them up a second time.
When you look at your old shingle’s installation pattern, you’ll likely notice that they are in a stepped angular pattern. They may be angled upward from left to right (installed by a left handed roofer), but usually they angle upward from right to the left which indicates they were installed by a right handed roofer. This means they started installing their shingles in a stepped pattern in the bottom left hand corner of the roof. In this case, you want to start stripping them off at the opposite corner of the roof, the top right, so that you are not working against the pattern.
From the top right corner, I’ll usually start pushing my ripper under the fourth or fifth row down, right along the very right hand edge of the roof. With my left hand, I gently, without ripping the shingles, lift the old shingles while loosening nails. The idea is to pull up all the nails but leave them attached to the shingles without breaking them up. You end up with 4 – 5 shingles held together intact, making it easier to pick up. Move over to the next row of steps and do the same thing. You can pick this piece up and throw it onto the last cluster that you pulled up. Now you have small pile of old shingles, still intact, making it much easier to pick up and throw in the bin.
Starting at the top of each consecutive stepped row, remove small manageable clusters. While a couple of people continue stripping, another person could be picking it all up and throwing it into the bin. If the stacks are placed fairly intact, the person picking them up can do it by simply sliding a spade under the stack and lifting. This goes pretty quick, as long as the piles are already made up by the people who are stripping and the debris isn’t too badly scattered about. The whole point is to reduce the amount of time shingles have to be handled. If you have to collect and stack after it’s been stripped, it will add another 50% to the time it takes to tear off the old shingles.
The same thing goes for pulling the nails while lifting the shingles. Be deliberate and do it once to minimize the amount of time you have to go back and pull nails that you’ve missed. It makes sweeping the roof afterwards much less difficult as well. There will always be a few nails left, but try to minimize it as much as possible.
Very often you will find rotted plywood on the roof deck. This will need to be replaced with new plywood. You don’t have to replace entire sheets of plywood. I will typically pre-cut the new plywood large enough to replace the rotted area. Then I’ll trace out the rotted area to cut out with the new pre-cut piece. Make sure your pre-cut piece is wide enough to be supported by the trusses. Trusses are usually spaced with 2 foot centers. In this case I would pre-cut my plywood in multiplies of 2 foot squares depending on the size of the rot. Remember, when installing plywood, to keep the grain of the plywood perpendicular to your supporting structure. If your plywood runs parallel to it, it has less strength and will sag.
If there is going to be rot, it usually occurs along the bottom edge of the roof and is usually pretty extensive. Most of the time the rot is less than 16 inches wide. In this case, I chalk a line along the length of the rot, 16 inches up from the bottom edge. I then run a circular saw on the chalk-line, along the length of the rot, and remove the old plywood. I cut my new plywood into 16 inch by 8 foot lengths to replace the old. In this way, there is no need to replace the entire plywood sheath.
Loading the roof with the new shingles can occur before you strip the roof. If you do that. you will want to place all the bundles on the side of the roof closest to the garbage bin. The reason for this is that you will want to shingle the side of the roof that is farthest away first so that you are avoiding foot traffic and dragging garbage across newly installed shingles.
The other option is to strip the entire roof first and then load your shingles. But remember, whatever you strip off will have to be covered with roofing paper as a temporary barrier to the elements before you load the roof and before you may have to leave the roof bare for the night.
Whenever you load a roof, you need to be mindful of the amount of weight you are putting in any one spot. A bundle of shingles weighs about 80 pounds. I typically stack my shingles in small piles of 6 bundles about a foot down from the ridge evenly spread along its length. This distributes the weight nicely and makes them easily accessible when installation gets underway.