Rolled roofing, also known as tar paper, is an asphalt-coated roofing material used as an underlayment for shingles or other roof coverings. It provides a water-resistant layer to protect the roof deck and insulate the interior from water penetration. Installing rolled roofing is an affordable roofing solution that can be done as a DIY project if proper techniques are followed.
In this comprehensive guide, we will cover everything you need to know about working with rolled roofing, including:
What is Rolled Roofing?
Rolled roofing, sometimes called tar paper, is a flexible asphalt-saturated roofing material that comes in rolls. It consists of a fiberglass or organic felt backing coated with asphalt and sometimes a surfacing material like mineral granules.
The main purposes of rolled roofing are:
- Waterproofing Layer – The asphalt coating provides a water-resistant barrier to prevent leaks.
- Underlayment – It is installed under shingles, shakes, metal roofing, or other roof coverings as a secondary waterproofing layer.
- Protection – It safeguards the roof deck from moisture damage.
Rolled roofing comes in different weights and grades. Heavier products have more asphalt and are more durable. Common types include:
- #1 Grade – Basic utility grade
- #30 Grade – Heavier and more moisture resistant
- #90 Grade – Heavy-duty multipurpose grade
Benefits of Rolled Roofing
Some key benefits of using rolled roofing include:
- Low Cost – Rolled roofing is an affordable roofing material option compared to shingles or metal roofing.
- Ease of Installation – Rolled materials are flexible and quick to install as an underlayment.
- Durability – It stands up well to weather, foot traffic, and UV exposure. Heavier grades last 20 years or more.
- Versatility – Can be used on nearly any roof type and paired with various roof coverings.
- Energy Efficiency – Provides an extra thermal layer to insulate attics.
- Leak Protection – Waterproof asphalt layer prevents leakage.
Overall, rolled roofing offers reliable performance at a budget-friendly price point for many homeowners and contractors.
Uses of Rolled Roofing
Rolled roofing has several common applications:
- Primary Roof Covering – On low slope or flat roofs, rolled roofing can be used as the finished exterior roof surface. It is installed in overlapping layers with exposed nails or adhesives. Common for porches, sheds, garages, and more.
- Secondary Underlayment – Used under shingles, shakes, metal panels, and other roof coverings as an added water barrier. Required by code under shake roofs.
- Temporary Roof Patch – Quick emergency repair material to patch holes, cover damaged areas, and prevent leaks.
- Roof Deck Protection – Laid as a shield over the roof decking before installing roof coverings. Protects from rain during construction.
- Valley Liner – Lines open roof valleys to channel water and prevent leakage.
- Pipe Flashing – Wrapped around plumbing vents, chimneys, and skylights as a weatherproof flashing.
Rolled Roofing Materials
Rolled roofing comes in a variety of base materials, weights, and surface finishes:
Base Materials
- Asphalt saturated organic felt – Made from recycled paper fibers and rag fibers saturated with asphalt. Economic option.
- Fiberglass mat – Woven fiberglass mat coated in asphalt. More tear-resistant and durable than organic felt.
- Polyester mat – Spun polyester fabric core provides strength. Used for specialized applications.
Weights
- #15 felt – 15 lbs per 100 square feet. Light duty for temporary repairs.
- #30 felt – 30 lbs per 100 square feet. Best for use as underlayment.
- #90 granular roll roofing – 90 lbs per 100 square feet. Can be used as primary roofing.
Surfacing
- Mineral surface – With embedded mineral granules to resist UV exposure. Used for primary roofing.
- Smooth surface – No granules. Used under other coverings as underlayment.
- Self-adhering – Factory applied adhesive side for ease of application.
How to Measure for Rolled Roofing Materials
It’s important to calculate how much rolled roofing you need for your project. To estimate:
- Roof Area – Measure the total square footage of your roof surface. Length x width.
- Overhangs – Add approx. 6-12 inches of extra material for overhangs.
- Overlap – Account for overlap of material. Usually 4-6 inches.
- Waste – Add at least 10% extra for waste, mistakes and ridge capping.
- Ridge Cap – If ridge capping, calculate linear feet of ridges x 18-24 inches wide.
- Valleys – Measure linear feet of valleys x 18-24 inches wide.
Always round up to the nearest full roll size when purchasing materials to ensure you have enough. Avoid running short on roofing partway through a job.
Cost of Rolled Roofing
Rolled roofing costs $15 to $75 per roll depending on the material grade and thickness. Basic #15 organic felt can cost as little as $15 per 208 sq.ft roll. Heavier #30 fiberglass underlayment runs $30 to $50 per roll. Mineral-surfaced 90 lb. material costs $60 to $75 per roll.
Besides the roofing itself, additional materials include:
- Underlayment – Felt, $20-40 per roll
- Fasteners – Roofing nails, $10 per 5 lb. box
- Adhesives – Asphalt plastic cement, $5-15 per gallon
- Flashing – Rolled flashing, $25-50 per 50′ roll
- Primer – Asphalt primer, $20 per gallon
- Accessories – Vent caps, edge metal, seals, $5-20 each
In total, rolled roofing installed costs $100 to $400 for all materials depending on roof size. Hiring a roofer adds $150 to $500 per square for labor.
Tools Needed for Installation
Installing rolled roofing is straightforward with some common tools:
- Utility Knife – Cutting rolled materials to size.
- Hammer or Nail Gun – Driving fasteners through material.
- Tape Measure – Measuring and cutting rolls accurately.
- Chalk Line – Marking straight guide lines for positioning.
- Caulk Gun – Applying adhesives and sealants.
- Roofing Shovel – Spreading hot asphalt adhesive.
- Broom or Roller – Pressing rolled roofing into place.
- Safety Equipment – Gloves, goggles, harness for working on roofs.
- Seam Roller – Rolling seams to bond layers.
Having the right tools allows for an efficient installation process. Investing in quality tools also makes the job easier.
How to Install Rolled Roofing
Installing rolled roofing properly is critical to achieve long-lasting waterproof performance. Follow these key steps:
1. Inspect and Prepare the Roof Deck
- Remove any existing roofing and debris.
- Inspect the roof deck for damage. Replace rotted areas.
- Ensure the deck is clean, dry and smooth.
- Cover holes or gaps with sheet metal.
2. Install Drip Edge Flashing
- Cut metal drip edge to size and place at eaves and rakes.
- Secure with roofing nails every 12 inches.
3. Apply Underlayment
- Roll out #30 roofing felt over the roof deck.
- Overlap sheets 2-4 inches and nail in place.
4. Prime the Surface
- Coat the underlayment with asphalt primer using a long nap roller.
- Allow primer to dry completely before continuing.
5. Install Rolled Roofing
- Roll material out and cut to size as needed.
- Position with 4-6 inch side laps and 6-12 inch end laps.
- Anchor in place with roofing nails spaced 8-12 inches apart.
6. Apply Adhesive Between Layers
- Coat seams and laps with plastic cement.
- Embed top layer into adhesive and roll seams with roller.
7. Install Ridge Caps
- Cut ridge roll material to fit ridge length.
- Bend over ridge and nail in place. Seal edges.
8. Complete Flashing Details
- Install pipe boots, edge flashing, vent caps as needed.
- Apply sealant around flashing edges.
Following proper rolled roofing installation procedures makes for a long-lasting, watertight roofing system. Always refer to local building codes and manufacturer instructions.
Rolled Roofing Repair Tips
Rolled roofing can develop leaks or damage over time. Here are some troubleshooting and repair techniques:
For small holes, cracks or tears:
- Clean area thoroughly and apply asphalt plastic cement 6 inches beyond damaged area in all directions.
- Embed patch of new rolled roofing into cement and seal edges.
For ridge cap or seam leaks:
- Lift edge and apply fresh adhesive in problem area. Re-seat with heavy rolling pressure.
- If needed, replace section of ridge cap or flashing.
For deteriorated sections:
- Cut out fully degraded sections back to solid material.
- Prime area then adhere new rolled roofing patch over cutout.
For extensive damage:
- Do full roof tear-off and re-roof with new rolled roofing materials.
With proper repairs, rolled roofing can continue to provide years of additional service life. Catch problems early before major damage occurs.
Rolled Roofing vs Shingles
Rolled roofing and asphalt shingles are two of the most common roofing materials. How do they compare?
Cost
- Rolled Roofing: $100-300 per square
- Asphalt Shingles: $300-700 per square
Durability
- Rolled Roofing: 10-20 years
- Asphalt Shingles: 20-30 years
Appearance
- Rolled Roofing: Smooth or mineral-coated.
- Shingles: Wide selection of color/style options.
Installation
- Rolled Roofing: Faster to install for DIY.
- Shingles: More complex installation.
Slope
- Rolled Roofing: For low slopes under 4:12 pitch.
- Shingles: Can be used on any sloped roof.
Weather Resistance
- Rolled Roofing: Prone to UV damage over time.
- Shingles: Excellent wind and weather resistance.
Overall, rolled roofing provides an affordable short-term roofing option, while shingles offer better looks, durability and performance on pitched roofs.
FAQs about Rolled Roofing
Some common questions about working with rolled roofing include:
How long does rolled roofing last?
On average, the lifespan of rolled roofing is 10-20 years depending on the material grade and exposure conditions. Heavier 90 lb. mineral-surfaced rolls can last up to 20-30 years as a primary roofing. Regular underlayment may last 10-15 years before replacement is needed.
What is the minimum roof pitch for rolled roofing?
Rolled roofing can be installed on slopes as low as 1/2:12 but optimal performance is achieved on slopes of 2:12 and greater. It is not recommended for completely flat or ponding roofs.
Should the drip edge go under or over rolled roofing?
The roofing drip edge should be installed first under the rolled roofing layers. This allows the roofing to overhang the drip edge to shed water properly.
How is rolled roofing installed on a flat roof?
For flat roofs, begin by nailing the perimeter edge strips. Then fully adhered the rolled roofing in overlapping layers with asphalt plastic cement. Coat and embed each layer fully. Finish with mineral-surfaced cap sheet.
How do you repair bubbling rolled roofing?
Blistering or bubbles can form when moisture is trapped under roofing. Carefully cut open, dry out area completely, re-adhere with asphalt cement, then patch. Improving roof ventilation can also help.
Can you install shingles over rolled roofing?
Yes, it is common practice to install asphalt shingles over existing rolled roofing to avoid a tear-off. Ensure the roofing is intact, then nail directly through both layers.
Rolled roofing can provide an affordable, user-friendly roofing option with proper installation. Follow manufacturer instructions and building codes for best results.
Conclusion
Rolled roofing offers a versatile and budget-friendly solution for residential or commercial roofs. When installed correctly using the steps outlined, it provides durable, long-lasting weather protection and insulation for buildings. key takeaways include:
- Rolled roofing comes in several material types and weights to suit various applications. Heavier grades provide more durability.
- It can be used as a primary roofing or secondary underlayment paired with shingles, metal roofing or other coverings.
- Careful measurements, overlapping seams, adhesive, and proper fastening are critical to achieve waterproof performance.
- Annual inspections and timely repairs help rolled roofing achieve its maximum service life. It is a roofing system that provides good value when maintained properly.
With the right materials and techniques, rolled roofing is an underlayment and roofing option within reach for motivated DIYers.