How to Install Roll Roofing

Installing a new roof can feel like a daunting task, but roll roofing (also known as MSR or Mineral Surfaced Roll roofing) is one of the most accessible and cost-effective ways to protect your property. Whether you are covering a backyard shed, a detached garage, or a low-slope porch, this blog will provide you with the professional knowledge needed to install roll roofing with confidence.

1. What Is Roll Roofing?

Roll roofing is a mineral-surfaced oil-based asphalt product sold in long rolls, typically 36 feet long and 36 inches wide. It is essentially a thinner, lighter, and more affordable version of the material used in asphalt shingles.

Material Types

• Mineral-Surfaced (MSR): The most common type, featuring a top layer of stone granules to protect against UV rays.

• Rubberized Asphalt (Modified Bitumen): A more flexible, durable, and expensive option often used for residential flat roofs. It handles temperature swings better than standard MSR.

Best Use Cases

• Roof Pitch: Roll roofing is designed for low-slope roofs. It is ideal for pitches between 1:12 and 2:12. (If your roof is steeper than 4:12, shingles are a better aesthetic and functional choice).

• Structures: Perfect for sheds, barns, workshops, and porches where a complex shingle look isn't required.

• Budget: It is the least expensive roofing material on the market, making it the go-to for DIYers on a budget.

2. Tools and Materials You Will Need

Before you climb the ladder, ensure you have these items staged and ready.

Materials Checklist

• Roll Roofing: Calculate your square footage and add 10% for overlaps and waste.

• Roofing Nails: 1-inch to 1-1/4 inch galvanized roofing nails.

• Roofing Cement (Lap Cement): This is the "glue" that seals your seams. You will need several tubes or a gallon bucket.

• Drip Edge: Metal flashing to prevent water from seeping under the roof edges.

• Roofing Underlayment: Usually 15-lb or 30-lb felt paper.

Tools Checklist

• Roofing Knife: A utility knife with "hook blades" makes cutting asphalt rolls much easier.

• Chalk Line: For snapping straight guide marks across the roof.

• Tape Measure: To ensure consistent overlaps.

• Roof Brush/Broom: To clean the deck of all debris.

• Hammer or Roofing Nail Gun: For securing the material.

• Safety Gear: Harness, gloves, eye protection, and rubber-soled shoes.

3. Safety First

Roofing is inherently dangerous. Follow these non-negotiable safety rules:

1. Weather Check: Only install on dry, calm days. Asphalt becomes brittle in the cold and dangerously slippery when wet. Ideally, work in temperatures above 50°F (10°C) so the material is flexible.

2. Fall Protection: If your roof is higher than one story or has a steep pitch, use a safety harness anchored to a secure point.

3. Ladder Safety: Always extend your ladder at least 3 feet above the roof edge. Use the 4-to-1 rule (for every 4 feet of height, the base should be 1 foot away from the wall).

4. Eye Protection: When cutting or nailing, granules and metal shards can fly toward your face.

4. Preparation Before You Begin

A roof is only as good as the surface beneath it.

Inspect the Decking

Check for soft spots, rot, or mold. If you step on a section and it feels "spongy," the plywood or OSB board must be replaced.

Surface Cleaning

Sweep the entire roof deck. A single pebble or old nail head left under the roll roofing will eventually poke a hole through the material, causing a leak.

Removing Old Material

While you can install roll roofing over one layer of old roofing, it is highly recommended to strip it down to the bare wood. This allows you to inspect the structure and ensures the new cement bonds correctly.

5. Step-by-Step Installation Instructions

Step 1: Install the Drip Edge

Start at the bottom (eaves) of the roof. Nail the metal drip edge directly to the wood deck. This ensures water shedding off the roof goes into the gutters rather than soaking the fascia boards.

Step 2: Apply Underlayment (Felt Paper)

Lay your felt paper horizontally, starting from the bottom. Overlap the higher rows over the lower ones by at least 2 inches. This acts as a secondary "backup" moisture barrier.

Step 3: Measure and Cut the First Roll

Unroll your material on a flat surface. Cut a length that spans the width of your roof plus about 2 inches of overhang.

Pro Tip: Let the cut rolls sit in the sun for 15 minutes. This "relaxes" the material so it lays flat without bubbles.

Step 4: Position and Nail the First Course

Start at the bottom edge of the roof. Align the roll so it overhangs the drip edge by about 1/2 inch.

• Nailing: Place nails 1 inch from the edges, spaced 6 to 10 inches apart.

• The Pattern: Work from the center of the roll outward toward the edges to prevent ripples.

Step 5: Apply Roofing Cement for Overlaps

For the second row, you must create a waterproof seal.

1. Snap a chalk line 2 inches above the top of the first row.

2. Apply a 2-inch wide band of roofing cement along the top edge of the first roll.

3. Lay the second roll so it overlaps the first, following your chalk line.

Step 6: Seal the Seams

Where two rolls meet end-to-end (vertical seams), overlap them by 6 inches. Apply a generous amount of roofing cement between the layers and nail the top layer securely. Press down firmly to ensure the cement "oozes" slightly at the edge—this confirms a total seal.

Step 7: Final Inspection

Check all nail heads. If any are "crooked" or not fully flush, fix them. Cover every exposed nail head with a small dab of roofing cement to prevent "rust-through" leaks.

Roll Roofing Maintenance Schedule: How to Get 10+ Years of Use

While roll roofing is a shorter-term solution, consistent maintenance can push its lifespan toward the 12-year mark. Use this checklist to stay ahead of leaks and wear.

Frequency	Task	Why It Matters
Every 6 Months (Spring/Fall)	Debris Removal	Leaves and twigs trap moisture on low-slope roofs, leading to rot and shingle granule loss. Use a soft broom—never a pressure washer.
Every 6 Months	Gutter Cleaning	If gutters clog, water backs up under the drip edge and the first course of your roll roofing, causing the wood deck to rot.
Once a Year	Seam Inspection	Seams are the #1 failure point. Check for lifting edges. If the lap cement looks dry or cracked, apply a fresh bead immediately.
Once a Year	Nail Head Check	Check for "nail pops" (nails pushing upward). Hammer them back in and cover the head with a dab of fresh roofing cement.
After Every Major Storm	Visual Scrutiny	Look for "bruising" from hail or tears from fallen branches. Early patching prevents the need for a full replacement.
Every 3 Years	UV Coating (Optional)	For rubberized or non-granulated rolls, applying a reflective silver "cool roof" coating can protect the asphalt from sun damage.

6. Common Mistakes to Avoid

• Wrong Overlap: Overlapping "uphill" (putting the lower roll over the higher one) will trap water and cause immediate leaks. Always work from the bottom up.

• High-Nailing: Nailing too far from the edge allows the wind to get under the material and rip it off.

• Ignoring Bubbles: If you see a bubble, do not ignore it. It will expand with heat and eventually crack the material. Flatten it out before nailing.

• Using the Wrong Cement: Ensure you are using "Lap Cement" specifically designed for asphalt roll products.

7. Cost Expectation

• Materials: Roll roofing typically costs $0.50 to $1.00 per square foot.

• Labor: If you hire a pro, expect to pay $2.00 to $5.00 per square foot for labor.

• Total DIY Savings: On a standard 500 sq. ft. garage, doing it yourself can save you over $1,500.

8. Frequently Asked Questions (FAQs)

Q1: How long does roll roofing typically last? 

A: Roll roofing generally lasts between 5 to 10 years. Because it is a single-layer material often used on low-slope roofs where water drains slowly, it wears down faster than multi-layered asphalt shingles.

Q2: Can I install roll roofing directly over my old shingles? 

A: While possible, it is not recommended. The uneven surface of the old shingles creates air pockets and "high spots" that can cause the new roll roofing to crack, bubble, or tear prematurely. For the best seal, always strip the roof to the bare wood.

Q3: What is the minimum roof pitch required for roll roofing?

A: You should not use roll roofing on a completely flat roof (0 pitch). It requires a minimum pitch of 1:12 (1 inch of vertical rise for every 12 inches of horizontal length) to ensure water sheds properly and doesn't pool on the seams.

Q4: Do I really need to use underlayment with roll roofing? 

A: Yes. Using a 15-lb or 30-lb felt underlayment (or a synthetic barrier) provides a critical second line of defense against leaks. It also protects the asphalt in the roofing material from reacting with resins in the wood decking.

Q5: Can I use staples instead of roofing nails? 

A: No. Staples do not have the "holding power" required to keep roll roofing secure during high winds. Always use galvanized roofing nails with a large head to prevent the material from pulling through.

Q6: What should I do if my roll roofing has wrinkles or "waves"? 

A: Wrinkles usually happen if the material is too cold or wasn't pulled taut during installation. To prevent this, unroll the material and let it sit in the sun for 15–20 minutes to "relax" before you nail it down.

Q7: How much should I overlap the seams? 

A: You should have a minimum of a 2-inch overlap for horizontal seams and a 6-inch overlap for vertical (end) seams. Always apply roofing cement (lap cement) between these overlaps to create a watertight bond.

Q8: Can roll roofing be used on a house, or is it only for sheds? 

A: While it is most common on sheds, garages, and porches, it can be used on residential homes if the roof pitch is low. However, keep in mind that it may lower the "curb appeal" and resale value of a home compared to shingles or metal.

Q9: Is roofing cement necessary for the entire roof? 

A: No, you only use roofing cement on the seams, edges, and over exposed nail heads. Applying it to the entire roof deck is unnecessary and can actually prevent the material from expanding and contracting with temperature changes.

Q10: How do I repair a small tear or hole in my roll roof? 

A: Small leaks can be fixed by applying a "patch." Cut a piece of roll roofing that is 2 inches larger than the hole on all sides, apply roofing cement to the bottom, press it firmly over the hole, and nail the corners, covering the nail heads with more cement.

Summary Checklist for Success

• Roof deck is clean, dry, and rot-free.

• Material sat in the sun to flatten before installation.

• All seams are overlapped correctly (bottom-to-top).

• Lap cement is visible at the edge of every seam.

• All exposed nail heads are "buttered" with cement.

Conclusion

Installing roll roofing is a rewarding DIY project that provides excellent protection for a fraction of the cost of traditional shingles. By following the bottom-up installation method, ensuring generous overlaps, and using quality lap cement, you can secure your structure for years to come.

Disclaimer: This guide is for informational purposes. Always check local building codes before starting a roofing project.