Complete Pergola Roof Restoration in Los Angeles: 50% OSB Replacement, Structural Repairs, and New Rolled Roofing Installation

In this real project by ProHands Handyman, we fully restored the roof of a pergola attached to a home. The scope included removing the old roofing system, replacing approximately 50% of the damaged OSB, reinforcing the structure, installing new metal drip edges, rebuilding the wall-to-roof flashing, and applying a new high-quality rolled roofing system.

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Why Flat Pergola Roofs in Los Angeles Often Fail

Flat and low-slope roofs on pergolas experience accelerated wear due to:

• Standing water and poor drainage

• Intense UV exposure

• Cracked, peeling, or aging rolled roofing

• Water intrusion at the connection to the house

• OSB swelling and delamination

• Improper or outdated flashing

• Deformation of old drip edges

Once moisture penetrates under the roofing, OSB panels soften, warp, and lose structural strength — leading to sagging and leaks.

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Step-By-Step: How We Restored This Pergola Roof

1. Detailed Roof Inspection

We inspected the pergola roof from the top and from below.

We found:

• Swollen and delaminated OSB panels

• Dark moisture stains

• Cracks and bubbles in the old rolled roofing

• Improper or deteriorated wall flashing

• A worn and ineffective drip edge

• Soft spots indicating long-term moisture intrusion

The roof required a complete rebuild of both the substrate and the waterproofing layers.

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2. Removing the Old Roofing System

We removed:

• The old rolled roofing

• The base underlayment

• Failing wall flashing

• The deformed drip edge

• All OSB panels that had lost their structural integrity

Underneath the roofing, we found multiple areas with clear signs of prolonged water penetration — especially near the wall connection.

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3. Replacing Approximately 50% of the OSB

Half of the roof deck had to be replaced.

Common issues we found:

• Delamination from water exposure

• Swollen edges and uneven panels

• Dark mold-like moisture markings

• Weak or loose attachment to joists

• Gaps caused by deformation

Installation of the new OSB:

• Removed all compromised panels

• Inspected and reinforced framing where necessary

• Installed new OSB sheets with proper expansion gaps

• Secured them with structural screws according to building standards

• Prepared a solid, flat deck for waterproofing

The result was a strong, stable substrate ready for roofing.

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4. Rebuilding the Wall-to-Roof Flashing (Pergola Attached to the House)

Since the pergola is attached directly to the home, the wall-to-roof transition is the most critical area for preventing leaks.

We completed:

• Removal of the old materials

• Surface preparation of the wall

• Installation of new, properly layered metal flashing

• Integration of flashing under the wall’s exterior surface

• Creation of a fully sealed, watertight transition

This prevents water from entering behind the roofing system — one of the most common failure points in attached pergolas.

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5. Installing a New Metal Drip Edge

The old drip edge was no longer functioning.

We installed a new, properly aligned drip edge that:

• Directs water away from the roof edge

• Prevents moisture from reaching the OSB

• Protects the perimeter from rot

• Improves the overall durability of the roofing system

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6. Installation of the New Rolled Roofing System

For this project, we used a modern mineral-surfaced rolled roofing material designed for Los Angeles climate conditions.

The installation process included:

• Laying the underlayment

• Rolling out roofing sheets with proper overlap

• Aligning materials for a smooth surface

• Heat-bonding or adhesive application (depending on manufacturer specs)

• Sealing all seams and transition points

• Trimming and securing edges for long-term waterproofing

The new roofing provides a clean, uniform look and strong weather resistance.

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7. Final Quality Inspection

We performed:

• A seam integrity check

• Flashing and wall-transition inspection

• Verification of perimeter sealing

• Full roof surface evaluation

• Complete site cleanup

The pergola roof is now fully restored, watertight, and ready for many years of reliable service.

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Benefits of a Full Pergola Roof Restoration

✔ Strong, stable OSB substrate

New OSB eliminates sagging and hidden moisture damage.

✔ Long-term waterproofing

Modern rolled roofing withstands UV, heat, and rain.

✔ Proper wall connection

The new flashing system prevents leaks at the most vulnerable point.

✔ Extends roof lifespan by 10–15+ years

A full restoration dramatically improves durability.

✔ Clean, smooth, attractive finish

The roof looks new and performs like a professionally built system.

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Signs Your Pergola Roof Needs Restoration

Homeowners should watch for:

• Cracks, bubbles, or lifting in rolled roofing

• Soft or sagging areas

• Dark moisture stains underneath

• Leaks after rain

• Gaps or separation where the roof meets the wall

• Swollen or uneven OSB panels

Any of these symptoms mean the roof needs immediate assessment.

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Why Homeowners Choose ProHands Handyman

We provide:

• Accurate diagnostics

• Honest, transparent recommendations

• Professional installation using the right materials

• Clean, responsible work on your property

• Fair pricing and reliable scheduling

• Experience with flat roofs, pergolas, and attached structures

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Conclusion

This Los Angeles pergola roof restoration demonstrates the importance of replacing damaged OSB, rebuilding proper wall flashing, installing new drip edge, and applying high-quality rolled roofing. Together, these steps fully renew the structure and protect it from water damage for years to come.

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Need Pergola or Flat Roof Repair in Los Angeles?

📞 818-401-7766

🌐 www.prohandshandyman.com

We serve Glendale, Burbank, Pasadena, Los Angeles, and nearby areas.

Call us — we’ll restore your roof professionally, cleanly, and with long-lasting results.