Asphalt Roofing Shingles - Pro Tips for Installing Them
Asphalt shingles are the most picked roofing material by contractors and homeowners in North America. Old roofs and roof replacements with asphalt shingles should be done by a professional roofing contractor, but if you're a homeowner who has the skills and proper tools to working safely on their roof can tackle this job. If this sounds like you here are a few basic roofing skills from industry pros to make your job easier.
Left to Right, Bottom to Top.
If you ever watched a professional roofing crew in action, you'll notice this is the pattern they will be using. Starting at the bottom left corner of a roof surface, working toward the right and upward from the eave line to the peak. A professional crew, where multiple workers are installing shingles at once, one worker will begin by installing shingles along the eave overhang, while other members of the crew begin to fill in the field, continuing to work from the bottom to the top.
Properly Flash Valleys and Seams
Have a roof leaf? 75% chance that leak is the result of a poorly flashed valley or seams. These are the areas where two roof planes meet, or at chimneys or other roof penetrations, so you want to ensure that you properly install roof flashing in these areas before the start of the shingle installation. Open valleys will be more durable and water-resistant when flashed than any blind alley. (In which the shingles overlap from one plane to the other and cover the valley.) Additionally, aluminum is recommended for all flashings used with asphalt shingles and it should be at least 0.019 inches thick.
Flashing isn't the easiest especially around objects with a lot of bend like a fireplace. So, if you decide to do the work on your roof and there is already flashing already installed, check its condition, if it's in good condition and not leaking try to leave it be. But, most roofing professionals will choose to install new flashings rather than relying on the existing flashings.
One Bundle At A Time
It's a good rule of thumb to always use all the shingles from one bundle before using shingles in the next bundle. The reason behind this is the colors may vary slightly between bundles, so when you use up the bundles one at a time, you avoid having different colors on the roof within the same area. You can minimize the color variations by ensuring all your bundles are all from the same manufacturing "lot".
Check the Roof "Deck"
All good roofing installations depend on the same thing, a solid, firm deck of plywood sheathing or OSB (oriented strand board). Make sure the sheathing is in good shape, and if installing new sheet material, make sure it is approved for roof-decking use. If using plywood, make sure it is labeled CDX, meaning that it is construction grade plywood intended for exterior use. If using OSB, make sure it carries approval from the APA - The Engineered Wood Association.
Install Full Tabs at Valleys or Rake Edges
If you can, install three-tab shingles so that the tabs falling over metal valleys or rake edges at the side of the house are at least 4'' wide. For even better results, use full-size shingles going into a closed valley (one without metal flashing) this will help eliminate nailing too close to the shingles centerline.
Use The Correct Nails And Proper Nailing Technique
The recommended attachment nails are galvanized steel or corrosion-resistant roofing nails. If you decide against galvanized, make sure that the chosen nails are used for the purpose to secure asphalt shingles to roof decking. Unsure, you can verify with local building code requirements and recommendations from the manufacturer.
At a minimum, asphalt shingles can be attached with just four nails for each shingle, but if installing in an area prone to high winds, six nails should be used for each shingle. Asphalt shingles have a nailing line—a line of sealant material intended to bond with the next row of shingles. Your nails should be placed just below this line, not inside it or above it. To reduce the wind lift forces acting over the shingles, do not nail them too high or too low. Never nail through the sealant strip of the shingle as it might affect the water flow over the roof.
Make sure nails are driven straight, not angled so that the sharp edges of the nail heads can cut into the asphalt shingles. Make sure that all fasteners penetrate at least 3 ⁄4 inch into the wood deck or completely through the sheathing.
Multiple Layers of Shingles Isn't Worth the Savings
An old (and out-dated) practice to save a few bucks, just lay a new roof directly over the old shingles without removing the old roofing. Not so fast, rules have changed and that method is now prohibited by code in most areas. A full tear-off of all old shingles is now required, with even most manufacturers implementing it in their warranties- Void if installed over existing shingles. A full tear-off ensures that the roof deck is flat and still in good shape. Remember, any flows, waves, or irregularity in the old roof deck will telegraph through to your new layer of shingles.
Ice & Water Membrane
When installed, an ice and water membrane acts like a double-guard against moisture penetration due to the impermeable rubberized fabric used. We suggest the use of ice and water membrane at the first few feet of the roof deck along eaves and whenever you need to line valleys. Additionally, if you live in an area where you experience freezing temperatures during the winter it's mandatory to put down the membrane where ice dams are a likelihood.
Strong/High Winds Consideration
If you live in parts of the country where you experience high winds, it's always smart to use shingles that have a reinforced nailing strip area on them. These strips increase the shingles' wind uplift-resistance against speeds of up to 110 mph. A good rule of thumb to follow, you'll want to have a minimum of (4) #9 11/2'' hex-head screws when you're installing shingles in high wind risk areas.
Properly Secure Ridge Cap Shingles
Where a ridge is covered with shingles rather than a roof vent, make sure each cap shingle is attached with two nails, one on each side of the peak. Typically, 13/4 to two-inch-long nails are used on the ridge.
Don't forget to do your research, don't jump right into this project. Research the different manufactures and what they offer so you know the best roofing materials for your home and needs. Should you choose a 3-tab shingle or an architectural shingle? Do you have to repair a leak? How much does it cost to install shingles? If you get to the point where the answers to these questions begin to scare you more than the heights do, hiring a professional roofing contractor like Robey Roofing is the way to go.