September 23, 2023

How to Install Asphalt Shingles

How to Install Asphalt Shingles

A Helpful Guide On How To Shingle a Roof

Learn the basics of installing an asphalt shingle roof

When it comes time to replace your roof, the amount of information available can be overwhelming. Many websites and videos explain in great detail how to tile a roof. This article from the experts at IKO Roofing will help you understand it all by outlining the basic steps and outlining the fundamental purpose of each component of the roofing system. This article is not a substitute for proper live training and IKO recommends that only properly trained professional roofing contractors get involved in roofing.

Here are the basic steps to shingle a roof.

1. The first step in any roofing project is always safety first.
Working at heights above a roof presents fall hazards and other safety concerns. IKO recommends that roofing work be performed by qualified professionals who know the best way to tile a roof and are fully trained in all aspects of roof construction safety. In addition, it is important to review applicable local building codes and ensure that the roof meets all requirements.

2. Understand the physics of how a sloped tile roof works.
Asphalt roofing shingles simply rely on the force of gravity to remove rainwater or melted snow. If the roof tiles and all accessory roof components are arranged and overlapped with this in mind, the roof should successfully shed water. In the dictionary, “tile” is defined as “distribute or arrange in a way that overlaps”. So now let’s look at the sequence of overlapping roof construction components to see how this applies.

3. Cover preparation.
Before installing any roofing material, make sure the roof deck is smooth, properly attached to the roof joists, dry, and free of gaps or holes. Having a clean, flat deck surface will help ensure that the newly tiled roof also looks smooth and flat when finished.

How to Install Asphalt Shingles
4. Work from the bottom up.
We’re not just working from the bottom of the roof, we’re also starting with the lowest layer, in terms of roof components. The asphalt roof shingles are the visible part and the first line of defense against the elements, but what’s under them really counts. The first material installed in the eaves is the drip edge. Literally provides a clean, sharp edge to the start of the roof and protects the bottom edge of the roof deck from water damage by preventing water from “defying gravity” and backing up “up” before exiting the roof.
How to Install Asphalt Shingles

5. Protection of the ice dam on the eaves.
If you live in an area where the weather includes significant cold weather in winter, you would wear boots to protect your feet from ice, sleet, and puddles, right? Well, your roof and the house under it need the same kind of protection that an ice and water shield is designed for. This thin, self-adhesive membrane is the next component and installs over the drip edge. The best way to prevent ice dam formation is to have an adequate vapor barrier in the attic, adequate attic insulation, and complete ventilation; however, an ice protection membrane is a smart component of the roofing system and is likely to be required by your local building code in cold climates. This ice and water membrane is typically applied to overhang 1/4 ″ -3/4 ″ eaves. To be fully effective, it must extend to the ceiling to a point at least 24 ″ within the vertical extent of the inside side of the wall. At this time, all roof valleys should also be covered with a membrane of ice and water. Why an ice and water protector? Because these membranes work on the principle that their rubberized asphalt coating seals around the shanks of overlapping shingle fasteners, adding an additional degree of protection against water spillage.
How to Install Asphalt Shingles

6. Subfloor for general protection of the secondary roof.
Next it’s time for the roof subfloor, which can be an asphalt-saturated felt or a synthetic roof subfloor. Both offer you quiet protection under shingles. While asphalt shingles will be the main water-repellent roof layer, installing a roof subfloor has many benefits. The felt is laid in horizontal rows, overlapping the eaves ice and water shield at 4 “and the flashing valley membrane at 6”. Note: If your home is in a region where an ice and water shield is not required, begin the installation of the subfloor at the eaves, protruding from the drip edge 1/4 “- 3/4”. Remember that drip edge we installed at the bottom of the roof? By raising the sloping edges of the roof (called “rakes”), it is placed on top of the underlayment. Although this appears to contradict the principle of overlap, installing the drip edge over the subfloor in the rakes creates a clean roof edge and provides the subfloor attachment with increased resistance to wind uplift. Also, any wind-driven rain blowing at the edge of the slope would cross the top lip of the drip edge and be placed on top of the subfloor rather than under the subfloor where it could cause a problem.

7. Covering the joints and valleys.
If a roof is to leak, it will most likely occur where the shingle layer is penetrated, interrupted, or meets a wall. These are the special areas that require flashing – an extra layer of water-repellent material to help water run downhill. Valleys can be open or closed; open valleys are not covered with tiles, closed valleys are. If your roof will have open valleys, which IKO recommends, now is when the valleys need to be lined with a wide, corrosion resistant metal preform. Closed valleys are completed during shingle installation. For longer roof performance, IKO highly recommends open metal valleys. Complete the underlayment and flashing application prior to applying roof shingles. The recommended flashing material is 28 gauge galvanized metal or equivalent non-staining corrosion resistant material (check local codes). Center a 914 mm (36 ″) wide strip of ice and water protective membrane in the valley. The product is temporarily fixed along one edge. Carefully remove the backing and put it in place, smoothing out any wrinkles. Start working from the eaves, allowing additional pieces to overlap by at least 150 mm (6 ″). Remove temporary nails. Center a minimum 28 gauge galvanized / prefinished metal valley siding 24 ″ wide and minimum 28 gauge in the valley, and secure with only enough nails to hold it in place, nailing only the edges. Overlap each piece of metal by at least 150mm (6 ″) and use asphalt plastic cement under each overlap section. Draw two chalk lines across the entire valley, 150 mm (6 ″) apart at the top 75 mm (3 ″) on each side of the valley and increasing the width 3 mm (1/8 ″) by every 300 mm (12 ″) Towards the bottom up to a maximum of 200 mm (8 ″). When shingles are being applied, lay them over the valley flashing, trim the ends to the chalk line, and nail the shingles at least 50mm (2 ″) back from the chalk line. Cut a 50 mm (2 ″) triangle in the top corner to direct the water down the valley and embed the valley end of each shingle in a 75 mm (3 ″) band of plastic asphalt cement. Flashing around plumbing chimneys and attic vents is critical because they are the most common roof penetrations. Also install metal flashing where shingles meet walls or chimneys. Ice and water protective membranes work well for flashing and help protect around skylights, dormers, turbines, and other tricky roof areas. Apply flashing materials in conjunction with the shingle installation procedure, with the flashing and shingles arranged to work together to protect around the joint areas.

There are two simple rules to follow:

  • Each flashing should overlap the one underneath by at least 3 ″ (75 mm), but should not be visible under the top overlap of the shingle.
  • Insert each step flashing into a 75 mm (3 ″) wide asphalt plastic cement application and nail in place. Next, the end of each shingle that overlaps a step flashing should also be well embedded in plastic cement.

Metal step flashing pieces are rectangular in shape and style, approximately 10 ″ (250mm) long and at least 2 ″ (50mm) wider than the face of the shingle being used. For example, when using metal flashing with shingles with a typical exposure of 143mm (5 5/8 ″) (such as traditional 3-tab shingles), the flashing size will be 250mm x 200mm (10 ″ x 8 ″ ). The 250 mm (10 ″) length is folded in half so that 125 mm (5 ″) reaches the wall surface and the other 125 mm (5 ″) extends to the roof deck. Note: Other sizes of step flashing are also acceptable. For IKO’s Cambridge shingle, with its largest exposure of 5 7/8 ″, a 10 ″ x 8 ″ flashing piece is still adequate, as the 8 ″ dimension is still at least 2 ″ larger than the dimension exposure of the tile. However, when displaying Crowne Slate, with its much larger display at 10 “, the flashing piece should be 10” x 12 “.

To install the flashing piece in the first row, place it over the end of the starter strip. Position so that the flange of the end tile covers it completely. Secure the horizontal flange to the roof deck with two nails. Do not fasten the flashing to the vertical wall. This will allow the flashing to move independently of any differential expansion and contraction that may occur between the roof deck and the wall. Place the second step flashing piece over the end shingle in the first course by placing it 143 mm (5 5/8 ″) above the bottom edge of the exposed asphalt shingle.

Make sure the tab on the second row shingle covers it completely. Secure the horizontal flange to the ceiling. The second and successive rows will continue with the end tiles illuminated as in the previous rows.

8. Shingles in the “field” of the roof.
Once everything that goes under the shingles has been properly prepared and installed, it is finally time to learn how to tile a roof. Regardless of what type or style of asphalt shingle you have chosen, the process is basically the same as mentioned above – it starts at the bottom and overlaps as you go through and up the roof. First, before field shingles are laid (“field” refers to the large extent of the roof within the confines of the eaves, ridges, and rakes), it is important to install a preparatory course of initial shingles that are manufactured specifically for that purpose. . But even if you design your own on site by cutting standard shingles to size, they both serve critical functions in the roof eave. They provide a sealant bond point for the first course of shingles and provide protection against water at shingle joints as well as cutouts. Professional contractors often recommend and use start strips along sloping edges to get a ruler from which all field trips can begin. In addition, these starter strips improve the wind resistance of the roof system on the rake. It is essential to follow the manufacturer’s instructions for the specific roof tile because not all tiles have the same exposure (the part of the tile that is visible once installed), offset (the lateral distance between joints in successive rows sometimes called ‘ staggering ‘or’ edge-to-edge ‘) and / or nailing. Problems can arise if the shingles receive too much or too little exposure or are not offset with the proper dimension in successive rows (rows of shingles). You need to drive nails in the proper location and drive them flush with the shingle, but not cut through it. Nailing the shingles correctly is critical to the wind resistance of the roof system. Proper nail placement is also a requirement for shingle limited warranty coverage. If you have chosen closed valleys, they are completed as the rows of shingles approach and cross the valley. The most common closed valley is a “closed cut” valley, where shingles are installed across the entire roof area on one side of the valley first, with each row of shingles extending at least 12 ″ across the center line of the valley. . As shingles are installed in the adjoining roof area, the end of each course of shingles is trimmed (cut) 2 ″ behind the center line of the valley.

9. The hip and ridge caps.
You’ve nailed the last tile on the field and you can see the finish line from here. Well done! In this case, the finish line is the hip and crest. When you install field shingles to the top of the roof, you can’t just “fold” them over the top. Instead, individual ridge tiles are used to straddle the ridge and dump water down any slope. There are several ridge tiles available on the market, but once again the procedure for installing them is based on the same fundamental principle of overlap. For the hips, start at the bottom and work uphill. Since the ridges are in a horizontal plane, the upward slope principle does not apply, so ridge shingles are typically installed like this: start at the end of the ridge opposite the prevailing wind direction, for optimal wind resistance of the ridge. On hip roofs, it is also acceptable to install the ridge caps starting at each end of the ridge, with the last piece installed in the middle of the ridge. The last piece of the ridge cap should be nailed in place, and since this will be the only spot on the roof where the nails will be directly exposed, the nail heads should be sealed and covered with a suitable roofing asphalt cement. Always remember to use longer nails for the ridge shingles. Because the nails must penetrate the ridge caps and the last row of roof shingles below, you will need longer nails to fully penetrate through them to the roof deck.