Installing asphalt shingles isn’t the most pleasant job in the world, but it’s a relatively simple one. And once you tackle a few rows you’ll get the hang of it pretty quick.
The following tips will focus only on a standard gable roof as it’s by far the most straightforward type of roof to shingle. Hip roofs and roofs containing dormers are a little trickier and should probably be left to those who have experience in that particular line of work.
I’ll start off by stating my belief in teamwork and putting a system in play. Ideally, you want a three man team with two on the roof installing and one on the ground “gumming” the shingles (applying plastic cement) and then running them up the ladder or scaffolding.
You don’t absolutely need three people, but it’s advisable to have at least one person with you. Seeing as how working on a roof can be dangerous, having another person on hand ensures that you have someone to witness any potential accidents and to take the proper course of action in the event of one occurring.
The first step is to determine the square footage of the roof. To calculate this, measure of the length and the width of one side of your gable roof and then multiply those two measurements together. The resultant number is that side’s square footage. Repeat this process for the other side of the roof and then add those two totals together to determine the roof’s overall square footage.
You then want to supply this number to your local building supply center so they can calculate exactly how many “squares” you’ll need. A square is equal to 100 square feet of coverage and is a term by which amounts of shingles are quantified.
As shingles come in different sizes, a square of any particular type can vary. Just remember that no matter what size or shape of shingle is being used, a square will always equal 100 square feet of coverage.
Any reputable business will be able to readily calculate the amount of shingles you’ll need, even taking standard wastage and ridge caps into account.
Ridge caps are sections of shingles that you cut yourself and that are used to cover the ridge or peak of your roof.
To cut ridge caps, place a shingle on a workbench with the tabs facing your body. You then make a couple of roughly 30 degree cuts in the upper half of the shingle for each tab, resulting in a total of 6 cuts that in the end will give you 3 ridge caps per shingle.
The building center will also calculate how many nails you will need and recommend what type to use. But as a quick tip, you’ll need about 3 lbs of nails for each square of shingles. The needed amount of plastic cement will be included as well.
Next, and contrary to popular belief, you don’t actually need to install an underlay of felt before the shingles go on. The purpose of this underlay is to essentially serve as a second layer of protection against leakage. Yet if your shingles are properly installed you shouldn’t have to worry about outright leakage anyway. Besides, the felt will be riddled with holes from the nails. So in the end, it provides little to no protection.
While covering your entire roof with felt is generally considered to be superfluous these days, it is standard procedure to apply a self-adhesive membrane more commonly known as ice guard around the perimeter of your roof to protect against long term water damage. Make sure to add ice guard to the material quote and if you want to save a few bucks, to leave the felt off.
If you are re-shingling a roof it’s perfectly acceptable to install shingles directly over any existing material, provided of course that there are no more than 3 layers of previously laid roofing. In any case, it is recommended that you actually strip the roof instead of taking the aforementioned shortcut. Asphalt shingles last on average anywhere between 15 and 20 years. This is a lot of time for structural degradation to occur, especially since roofing materials and standards couldn’t have possibly been as good 20 years ago as they are today. So by stripping the roof you get an opportunity to assess any accrued damage and to make any necessary repairs.
When stripping your roof it’s advisable to use what’s known as a roofer’s spade. These gems resemble a square top shovel, but have a notched blade up front and an attached fulcrum on the underside, all designed to make the prying up of shingles an easy task.
To avoid an incredible mess, rent a dumpster and have it delivered on site and within tossing distance of the roof. This way you can basically toss or shovel the scrap shingles directly into the dumpster as you go.
When all shingles and accompanying materials have been removed, give the roof a final inspection for any nails you may have missed. Now it’s time for the ice guard. These rolls of waterproof membrane come in boxes with installation instructions included. Simply follow the directions and you’ll be fine.
While the two guys on the roof are installing the membrane, the ground man should begin applying plastic cement to the shingle tabs to ensure they will stick down after they are installed. To do this you’ll need a workbench and a small trowel. Place a shingle upside down with the tabs facing away from your body. Use your trowel to scoop plastic cement from its container and then apply a thin layer around the edges of each tab. For example, if you start from the left you come up the left side, then across the top, then down the right side, then swoop down and around the factory cut and up the left side of the next tab and so on. Remember to stay above the factory adhesive strip and to stay about one eighth of an inch away from the edges to avoid plastic cement being squished out as the shingle is being installed.
When your first shingle has been gummed, move it aside and gum another one in the same fashion. Then you place the second shingle directly on the first one, gummed sides facing each other. Repeat this process until you have a comfortable stack to carry. Then you shoulder the stack and run them up to the roof to be installed. Your aim in this job will be to keep the two men on the roof supplied as they install.
The first course of shingles goes on dry (no plastic cement) and with the tabs pointing up towards the peak. They should extend out over the eave about three eighths of an inch. Place four nails in each shingle, staying roughly half an inch away from all edges and avoiding the factory tar strip by staying under it. When you get to the edges of the roof, make sure the shingles extend three eighths out over there as well.
The next course of shingles is wet (with plastic cement) and is installed with the tabs pointing down. Determine the center of the roof and center the first shingle on that point, making sure that your tabs are flush with the shingle directly beneath. Nail this shingle as previously mentioned, only this time nail slightly above the tar strip as opposed to below it. Install the entire row as described, making sure to stay flush with the starter strip on both the eave and roof edges.
Start your next course in the same place, but cut off half a tab to stagger your joins. The course following this one will start with a full shingle and the process repeats itself until you reach the peak.
There is no need to strike chalk lines so long as your first course is straight. Asphalt shingles have small tabs on either side that you fold back so that they hook into the shingle beneath them in the appropriate place.
On your last course you should cut your shingles flush with their side of the ridge.
Follow all previous steps to shingle the other side of the roof. With your last course on that side, allow shingles to overlap the ridge and then fold them and nail the ends down on the other side.
Next you cut the needed amount of ridge caps as previously described. Gum the ridge caps in the same way you would a full shingle. The first ridge cap to be installed is cut like the others except that it is cut straight and not on an angle. To install you simply center the actual tab on the ridge, flush it with the other shingles on the roof edge and place two nails on the cut side where the next ridge cap will overlap and hide them. Repeat this process with all other caps until the ridge has been sealed.
If you encounter a chimney, simply nail aluminum flashing around the perimeter and then seal it with plastic cement. Then you shingle it over as you get to it, cutting accordingly.
The same goes for vent pipes, except you can purchase what’s known as a collar, which consists of an aluminum base (flashing) with a rubber gasket that fits and seals the pipe down near the roof. To install you nail and seal the flashing with plastic cement as you would normally do and again, shingle it over as you get to it, cutting accordingly.