The Fundamentals of Asphalt Shingle Roofing
Asphalt shingles installation is the most popular roofing method in North America, covering approximately 80% of residential roofs. If you’re considering installing them yourself, here’s what you need to know:
| Quick Guide: Asphalt Shingles Installation |
|---|
| 1. Safety First: Use harness, non-slip shoes, and proper ladder setup |
| 2. Materials Needed: Shingles (3 bundles per 100 sq ft), underlayment, drip edge, roofing nails |
| 3. Preparation: Clean roof deck, install drip edge at eaves, apply underlayment |
| 4. Installation: Start with starter strips, then work bottom-up with proper overlap |
| 5. Nailing Pattern: 4 nails per shingle (6 in high-wind areas) just below adhesive strip |
Installing asphalt shingles correctly is crucial for ensuring your roof remains watertight and durable for its expected 20-30 year lifespan. While DIY installation can save an average of $5,300 in labor costs, it requires careful attention to detail and safety precautions.
The process involves preparing the roof deck, installing underlayment and drip edges, and then carefully placing overlapping rows of shingles from the bottom up. Proper nailing technique is essential – each shingle typically requires four nails placed just below the adhesive strip.
Weather matters: Plan your installation during mild, dry weather with temperatures between 40-85°F. This ensures proper adhesion of the shingle sealing strips and safer working conditions.
I’m Carlos Yzaguirre, President of Apex Roofing & General Contractors in San Antonio, where I’ve overseen hundreds of asphalt shingles installation projects across Texas, ensuring each roof meets strict quality standards and building codes for maximum durability and performance.
Safety First & Jobsite Prep
Let’s face it – roofing work can be dangerous. About one-third of construction fatalities come from roof falls, which isn’t something I share to frighten you, but to emphasize just how crucial proper safety measures are before you tackle your asphalt shingles installation project.
Choosing Personal Protective Equipment for Asphalt Shingles Installation
Your safety gear is your first line of defense when installing asphalt shingles. Think of it as your roofing uniform – you wouldn’t step onto the field without the right equipment, so don’t step onto your roof without it either!
Fall protection harnesses are non-negotiable, especially on roofs steeper than a 4:12 pitch. These lifesavers connect to secure anchor points and can literally be the difference between a minor slip and a serious injury. Pair this with non-slip roofing shoes that grip those sloped surfaces like your life depends on it (because it might).
Your hands will thank you for wearing heavy-duty work gloves that protect against sharp edges, while safety glasses keep debris from turning your eye into a landing zone. Don’t forget a hard hat – tools have a funny way of deciding to take gravity-powered trips when you least expect it.
I always recommend wearing long pants and sleeves too, even in our San Antonio heat. They protect against scratches and sunburn – trust me, nothing makes finishing a roof harder than looking like a boiled lobster after day one!
OSHA requires fall protection for heights of 6 feet or more, but I follow this rule even for single-story homes. And please, work with a buddy whenever possible. They can steady your sturdy ladder (which should extend at least 3 feet above the roof edge) and provide immediate help if something goes wrong.
Site & Property Preparation Checklist
Before the first shingle goes up, your property needs some attention too. Give your lawn a fresh cut – it makes finding those escaped nails much easier during cleanup. Your flowerbeds will appreciate being covered with tarps, and your vehicles will thank you for moving them away from the splash zone.
Take some “before” photos of your property, especially your driveway. It’s not that we’re expecting damage, but it’s always smart to document pre-existing conditions. While you’re at it, be a good neighbor and give folks a heads-up about the upcoming noise and activity.
Set up a designated staging area for your materials – ideally somewhere close to your roof access point. This saves countless trips up and down the ladder. Speaking of materials, arrange for a dumpster or trailer to collect the old roofing waste. Our Texas winds have a way of turning loose debris into neighborhood decorations if you’re not careful!
Check your local building codes and secure any necessary permits. In San Antonio and surrounding communities like Helotes and Leon Valley, requirements can vary, and the last thing you want is a code violation halfway through your project.
Our Texas weather deserves special consideration too. The scorching summer heat can make shingles soft and easy to damage during installation, so early morning work is often your best bet. Always check the forecast and ensure you have at least a week of clear weather ahead.
Before you begin your asphalt shingles installation, consider having professionals assess your roof’s current condition. Visit our Roof Inspections page to schedule a thorough evaluation of your roof deck to ensure it’s ready for a new installation.
Need expert guidance on your roofing project? Apex Roofing & General Contractors offers free estimates – simply reach out to our San Antonio roofing experts to schedule your complimentary inspection with trusted professionals.
Measuring, Calculating & Ordering Materials
Getting your measurements right is the make-or-break first step of any successful asphalt shingles installation. I’ve seen too many weekend warriors make the costly mistake of eyeballing their roof size—ending up with either a half-finished project or hundreds of dollars in unused materials.
How to Measure a Roof Without Climbing
Not everyone feels comfortable scaling their two-story home with a tape measure, and honestly, you don’t need to! Here in San Antonio, where summer temperatures regularly hit triple digits, staying on solid ground can be the smarter choice. Try these methods instead:
Several satellite measurement apps have become remarkably accurate in recent years. Apps like RoofSnap or EagleView can provide detailed measurements using aerial imagery—perfect for planning your project while keeping your feet firmly planted on terra firma.
If you prefer the old-school approach, measure your home’s footprint from the ground (length × width) and then account for your roof pitch. A standard 4:12 pitch (rising 4 inches for every 12 inches horizontally) adds about 5% to your roof’s surface area. Steeper roofs common in some San Antonio neighborhoods will need a higher adjustment factor.
Estimating Bundles & Accessories for Asphalt Shingles Installation
Once you’ve got your square footage figured out, it’s time for some roofing math:
Convert your total square footage to “squares” (each square equals 100 square feet)—the universal measurement in roofing. For standard asphalt shingles, the three-bundles rule applies: you’ll need three bundles to cover each square.
Always add a waste factor—this isn’t being pessimistic, it’s being realistic! For a simple gable roof, add 10-15% extra. If your home has multiple dormers, valleys, or a complex design like many newer homes in Stone Oak or Alamo Heights, bump that up to 15-20%.
Don’t forget the supporting cast of materials. You’ll need approximately 320 nails per square (about 2 pounds), underlayment (one roll typically covers 400 square feet), and enough drip edge to go around your roof’s entire perimeter. For valleys and eaves, especially important in our occasional Texas downpours, include ice and water shield for extra protection.
| Comparison: 3-Tab vs. Architectural Shingles |
|---|
| 3-Tab Shingles |
| 3 bundles per square |
| Lower cost ($90/square) |
| 20-year lifespan |
| Less wind resistance |
| Flat appearance |
When calculating ridge caps for hips and ridges, divide the total length by 35 to determine how many bundles you’ll need. These specialty shingles provide both weather protection and that finished look every great roof deserves.
If all this measuring and math feels overwhelming, our team at Apex Roofing & General Contractors offers free roof measurements as part of our estimate process. For complete peace of mind with your Roof Replacement project, reach out to our San Antonio roofing specialists to request your free estimate today.
Preparing the Roof Deck & Installing Underlayment
A successful asphalt shingles installation begins with thorough roof deck preparation. Think of this as the foundation of your entire roofing system – if it’s not done right, even the best shingles won’t perform properly.
Drip Edge & Flashing Basics
The drip edge is your roof’s unsung hero – this simple metal strip guides water away from your fascia and into your gutters, preventing rot and water damage. Here in San Antonio, where we can get those sudden summer downpours, proper drip edge installation is essential.
Start by installing the eave drip edge along the bottom edge of your roof before you lay any underlayment. The rake drip edge (along the sides) comes later, after the underlayment is down. When joining sections, overlap them by at least 1½ inches, always with upper pieces overlapping lower ones – water flows downhill, after all! Secure everything with roofing nails every 8-10 inches.
Flashing is your roof’s waterproofing system for all those tricky spots. At wall intersections, step flashing protects the seam, with each piece overlapping the previous one like shingles. Chimneys need special attention with base flashing, step flashing, and counter flashing working together. For plumbing vents, rubber boots create a watertight seal, while valleys need either metal or membrane flashing to handle the concentrated water flow.
If you’re tackling vent and stack flashing yourself, I’d recommend watching some detailed tutorials – these areas are common leak points if not done correctly. This video guide offers excellent step-by-step instructions.
Underlayment Choices & Installation Sequence
Underlayment is your roof’s backup plan – if water somehow gets past your shingles, this layer prevents it from reaching your deck and home interior. In our Texas heat, quality underlayment also helps regulate attic temperatures.
Before laying underlayment, give your roof deck a thorough cleaning and inspection. Replace any damaged or soft sheathing – this isn’t the place to cut corners. Your underlayment options include:
Traditional felt paper (15# or 30#) is budget-friendly and has been used for decades. It works well but can tear during installation and doesn’t hold up as long as newer options.
Synthetic underlayment costs more upfront but offers better durability, tear resistance, and is lighter to work with – a real back-saver on hot San Antonio summer days!
Self-adhering membrane (ice and water shield) provides superior protection in critical areas like valleys and eaves. While ice dams aren’t common in South Texas, these membranes still protect against wind-driven rain in vulnerable spots.
When installing underlayment, always start at the bottom edge and work upward – just like the shingles will. Overlap horizontal seams by 2-4 inches and vertical seams by 6 inches. For low-slope roofs (less than 4:12 pitch), double-layer your underlayment for extra protection. Secure everything with cap nails or plastic-capped roofing nails to prevent tearing.
Pay special attention to valleys – they channel a lot of water! Install ice and water shield in valleys first, extending at least 18 inches on each side of the valley center.
The International Residential Code (IRC R905.2) has specific requirements for underlayment based on roof pitch. Our professional installers at Apex Roofing are well-versed in these codes and ensure every roof meets or exceeds these standards.
For a professional asphalt shingles installation that stands up to our unique San Antonio climate, visit our Roof Installation page to learn about our expert services. You can also contact our San Antonio roofing team to schedule a free roof inspection.
Step-by-Step Asphalt Shingles Installation Guide
Now that your roof deck is prepared with underlayment and drip edge, it’s time to tackle the main event – the actual asphalt shingles installation. This is where your attention to detail will truly make or break your roofing project.
Laying the Starter Strip for Proper Asphalt Shingles Installation
Think of your starter strip as the foundation of your entire shingle system. Get this wrong, and you’ll be fighting an uphill battle the rest of the way.
Start by either purchasing manufactured starter strips (my recommendation for beginners) or creating your own by cutting the tabs off regular shingles. Position these strips with the adhesive facing upward and toward the eave – this creates that crucial first line of defense against wind uplift.
Allow a ¼ to ¾ inch overhang beyond the drip edge – enough to direct water into your gutters but not so much that wind can catch underneath. Secure each starter with 4-6 nails placed 1-3 inches up from the eave edge.
Here’s a pro tip from our San Antonio crews: Complete the entire starter strip row along all eaves before moving to your first course of regular shingles. This gives you a straight, solid foundation for everything that follows.
Installing Field Courses & Maintaining Stagger
With your starter strip in place, it’s time to lay your first course of full shingles directly over it. Align them precisely with the bottom and side edges of your starter strip for a clean appearance.
The nailing pattern is crucial – place four nails per shingle (six if you’re in one of San Antonio’s higher-wind areas) just below the adhesive strip. Your nails should be 11 or 12-gauge with 3/8″ heads, driven straight and flush. Too deep damages the shingle; too shallow and they’ll work loose. Position nails 1 inch in from each end with the others evenly spaced between.
Creating a proper stagger pattern prevents water from finding a direct path to your roof deck. For a standard pattern, cut 6 inches off the first shingle in your second course, 12 inches off the first shingle in your third course, and 18 inches off the first shingle in your fourth course. When you reach the fifth course, return to a full shingle and repeat the pattern all the way up.
Maintain the standard 5⅝” exposure for 3-tab shingles, and snap horizontal chalk lines every few courses to keep everything straight. The Texas sun can make working on a roof challenging, so I recommend starting early in the morning when it’s cooler and the shingles are less likely to be damaged during handling.
For a more detailed visual guide, check out How to Install Roof Shingles for additional illustrations.
Tackling Valleys, Hips, Ridges & Penetrations
Valleys – where two roof planes meet – require special attention since they channel significant amounts of water. You have two main options:
With a closed-cut valley, shingles from one side extend across the valley center, while shingles from the other side are cut to the valley line. This creates a cleaner look but requires more precision.
An open valley leaves metal flashing exposed with shingles cut back on both sides. This is more forgiving for DIYers and offers excellent water shedding in our occasional Texas downpours.
For roof penetrations like plumbing vents, install the appropriate flashing over the underlayment but under the surrounding shingles. Cut your shingles to fit snugly around the flashing, then seal with a quality roofing cement to prevent leaks.
Hips and ridges get special treatment as your finishing touch. You can use pre-manufactured ridge caps (easiest) or create your own by cutting regular shingles into appropriate sizes. Install from the bottom up on hips, or from both ends toward the middle on ridges. Each cap should overlap the previous by about 5 inches, secured with two nails.
For a visual demonstration of proper hip and ridge capping techniques, check out this helpful video tutorial.
If you’re feeling overwhelmed by any of these more technical aspects of asphalt shingles installation, Apex Roofing & General Contractors specializes in perfect installations throughout San Antonio and the Hill Country. Contact our roof installation experts for a free inspection and estimate.
Codes, Slope Variations & Common Mistakes to Avoid
When it comes to asphalt shingles installation, following building codes isn’t just about staying legal—it’s about ensuring your roof will protect your home for decades. The International Residential Code (IRC R905.2) provides specific guidelines that every installation must follow, whether you’re a DIY enthusiast or a professional.
Special Considerations for Low-Slope Asphalt Shingles Installation
If your roof has a gentle pitch between 2:12 and 4:12 (meaning it rises 2 to 4 inches for every 12 inches horizontally), you’ll need to take extra precautions. Standard installation methods simply won’t cut it on these low-slope roofs.
First, you’ll need to apply double underlayment—two complete layers covering your entire roof deck. This provides crucial additional protection against water that moves more slowly off less-angled surfaces. For even better defense, especially in San Antonio where we occasionally get those Texas-sized downpours, consider using self-adhering ice and water shield over the entire deck.
Your nailing pattern needs upgrading too. Instead of the standard four nails per shingle, use six. This extra fastening helps prevent wind uplift, which low-slope roofs are more vulnerable to. Additionally, applying a small amount of roofing cement under each tab creates a secondary seal against wind-driven rain.
Asphalt shingles should never be installed on roofs with slopes less than 2:12—these surfaces simply don’t drain quickly enough to prevent water infiltration.
Installing on Steep Slopes & Mansards
On the opposite end of the spectrum, steep slopes (greater than 21:12) present their own unique challenges. When gravity is working this hard against you, both safety and installation techniques need adjustment.
Secure footing becomes critical, so install temporary roof jacks and planks to create stable working platforms. Rather than working vertically up the roof, install shingles horizontally across the roof—this approach is both safer and more efficient on steep pitches.
Your fastening system needs reinforcement too. Use six nails per shingle instead of four, and hand-seal each shingle with dabs of asphalt roof cement (conforming to ASTM D4586). For laminated shingles, apply four quarter-sized spots of cement; for three-tab shingles, two spots will do. This additional adhesion prevents shingles from sagging or slipping on these extreme slopes.
When working on steep mansard roofs, which are almost vertical in some sections, patience is key. Take your time and focus on precise alignment and fastening—mistakes are much more visible on these architectural features.
I’ve seen plenty of roof failures in my years with Apex Roofing, and most stem from these common installation mistakes:
- Improper nailing where nails are driven too deep (damaging the shingle), at an angle (reducing holding power), or in the wrong location (missing the double-thickness area)
- Insufficient ventilation that traps heat and moisture, drastically reducing shingle life
- Working from the top down instead of starting at the eaves and moving upward
- Skipping the starter course or installing it incorrectly, leading to edge leaks
- Misaligned courses from not using chalk lines as guides
- Incorrect overhang at the drip edge—too much invites wind uplift, too little allows water to seep into fascia
- Mixing different brands or types of shingles, creating both appearance and performance issues
For comprehensive information about all your residential roofing options and professional installation that avoids these pitfalls, visit our Residential Roofs page.
At Apex Roofing & General Contractors, we’ve seen and fixed countless DIY installation mistakes across San Antonio. While we admire the ambition of homeowners tackling their own roofing projects, we’re always here to provide guidance or step in if things get overwhelming. Connect with our San Antonio roofing professionals for a free inspection and estimate on your roofing project.
Maintenance, Ventilation & Warranty Essentials
You’ve finished the asphalt shingles installation, but your roofing journey isn’t quite over. Think of your new roof like a car—it needs regular maintenance, proper airflow, and understanding the warranty to maximize its lifespan and protect your investment.
After my years installing roofs across San Antonio, I’ve seen how proper post-installation care can add years to a roof’s life, especially with our intense Texas sun and occasional severe storms.
Post-Install Checklist for Long Roof Life
Before you consider your project complete, take a Sunday afternoon to perform these final checks:
Walk your property and clean up any stray nails or debris from the installation—your lawnmower will thank you! Then grab a ladder and inspect all your newly installed shingles for proper sealing. Pay special attention to areas around chimneys and vents where leaks commonly develop.
Check for any exposed nail heads that might have been missed during installation. These tiny overlooked spots can become major leak points during our heavy Texas downpours. A small dab of roofing cement on each exposed nail head provides excellent protection.
Don’t forget to examine your attic! A quick moisture scan with a flashlight can reveal potential problem areas before they become serious issues. Look for any signs of light coming through (which means water can get in too) and check for proper insulation distribution.
Document your beautiful new roof with photos from multiple angles. These aren’t just for sharing on social media—they’re important documentation for warranty purposes and will be invaluable if you ever need to file an insurance claim after a storm.
Proper ventilation is absolutely critical for shingle longevity in our San Antonio climate. Without adequate airflow, summer temperatures in your attic can soar above 150°F, literally cooking your new shingles from underneath! The building code requires a ventilation ratio of 1:150 (one square foot of ventilation for every 150 square feet of attic space), with a balanced system of intake vents at the eaves and exhaust vents at or near the ridge.
Most manufacturer warranties have specific requirements that must be followed to keep your coverage valid. These typically include:
- Installation according to their detailed instructions (which is why keeping those wrappers and packaging is important)
- Proper ventilation meeting or exceeding local building codes
- Using matching components from their specific roofing system
- Documentation of the installation process
For homeowners in Bexar County, I recommend scheduling annual roof inspections, ideally before summer storm season. Our local climate presents unique challenges—from scorching heat to occasional hail—that can impact your roof’s performance.
For comprehensive information on proper asphalt shingles installation and maintenance guidelines, the Asphalt Roofing Manufacturers Association provides excellent resources custom to different climate zones.
A well-maintained roof is your home’s first line of defense against the elements. At Apex Roofing & General Contractors, we’re always available to answer questions about maintaining your new roof. For professional roof inspections or maintenance services, visit our Residential Roofs page or connect with our San Antonio roofing team to schedule a free inspection with our experienced professionals.
Frequently Asked Questions about Asphalt Shingles Installation
What season is best for asphalt shingles installation in Texas?
Here in San Antonio, timing your asphalt shingles installation can make a big difference in both the installation process and the long-term performance of your roof.
Spring and fall are your sweet spots—those gorgeous moderate days when it’s not too hot and not too cold create perfect working conditions. The adhesive strips on shingles need temperatures above 40°F to properly activate and create that watertight seal we’re looking for.
Summer installations aren’t off the table, but we recommend getting an early start. Those scorching Texas afternoons can make shingles as pliable as warm taffy, which means they’re easier to damage during installation. Many of our professional crews at Apex start at dawn during summer months to beat the heat.
Winter can work too, believe it or not! Our mild South Texas winters often provide plenty of days above that crucial 40°F threshold. Just keep an eye on the forecast and aim for a stretch with minimal chance of rain for at least a week after installation.
Can I install asphalt shingles myself or should I hire a pro?
The DIY route is tempting—I get it! Saving around $5,300 in labor costs is nothing to sneeze at, and there’s definite satisfaction in pointing to your roof and saying, “I did that.”
But before you climb that ladder, consider what you’re getting into. Roofing consistently ranks among the most dangerous construction jobs, with falls accounting for one-third of construction fatalities. That statistic isn’t meant to scare you, but it does deserve serious consideration.
Beyond safety, there are practical considerations. Most DIY installations take 3-5 days compared to the 1-2 days our professional teams need. There’s also a steep learning curve—small mistakes in nailing patterns or underlayment installation can lead to big problems down the road.
Manufacturer warranties often come into play too. Some premium shingle warranties are only valid with professional installation, which could cost you thousands if problems develop years later.
Professional installation makes particular sense if you have:
– A multi-story home or complex roof design with multiple valleys
– A steep slope (anything over 6:12 pitch gets challenging quickly)
– Any physical limitations or discomfort with heights
– A desire for those extended manufacturer warranties
How many nails per shingle are required by code?
Getting the nail count right isn’t just about following rules—it’s about ensuring your roof can withstand our occasional Texas windstorms. The International Residential Code specifies:
For standard slopes (4:12 to 21:12), you’ll need a minimum of four nails per shingle. These should be placed just below the adhesive strip, with one nail about an inch from each end and the other two spaced evenly between them.
If you’re in a high-wind area or have a steep roof (greater than 21:12 pitch), bump that up to six nails per shingle. The same goes for low-slope roofs between 2:12 and 4:12, which need extra fastening to prevent wind uplift.
Those nails need to meet specific requirements too—minimum 12-gauge galvanized steel with at least a 3/8-inch head diameter. They should be long enough to penetrate through all roofing layers and at least 3/4 inch into the roof deck (or completely through thinner sheathing).
Proper nail placement is just as crucial as quantity. Nails driven at an angle or overdriven below the shingle surface can actually create points of failure rather than reinforcement.
At Apex Roofing & General Contractors, we provide free roof inspections to help you determine the best approach for your specific situation. Contact our San Antonio roofers to schedule your no-obligation assessment and get all your asphalt shingles installation questions answered by local experts.
Conclusion
Installing asphalt shingles is quite the project, isn’t it? Whether you’ve been following along with our guide or just considering your options, you now understand the careful planning, proper materials, and attention to detail required for a successful roof installation.
While the DIY route is certainly possible for those with the right skills and a head for heights, many of our San Antonio neighbors find that professional installation offers something invaluable – peace of mind. Not to mention the warranty protection and superior results that come with expert craftsmanship.
Here at Apex Roofing & General Contractors, we’ve seen the unique challenges of roofing in Texas. Our certified team has installed countless asphalt shingles roofs designed specifically to withstand our local climate extremes – from those scorching summer days to those unexpected severe storms that can roll through the Hill Country.
We understand that every homeowner’s situation is different. Maybe you’re the hands-on type who’s ready to tackle this project yourself. Or perhaps you’d rather leave it to the professionals who can complete your roof in a fraction of the time. Either way, we’re here to support you – whether you need advice, quality materials, or our complete installation services.
What sets us apart is our unwavering commitment to quality workmanship and straightforward communication. It’s why homeowners throughout San Antonio, Helotes, Leon Valley, and all of Bexar County have made us their trusted roofing partner.
Ready to explore your options further? Visit our Asphalt Shingle Roofs page for more details about our asphalt shingles installation services. You can also learn about our experienced San Antonio roofers to find why we’ve become the preferred roofing contractor in the region.
Your new roof is just a click away. Visit our website to schedule your free inspection and estimate with Apex Roofing & General Contractors today.
