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Pennsylvania Re-Roofing Code R908 Simplified for Homeowners

Posted on : June 15, 2023

Pennsylvania Re-Roofing Code R908 Simplified for Homeowners

Homeowners often encounter various challenges when it comes to maintaining and repairing their roofs. Understanding the Pennsylvania roofing codes, specifically Section R908 is essential for homeowners who are planning to remodel or replace their old roofs.

In this article, I will decode every requirement stated in Pennsylvania residential re-roofing code R908 in simple language. As a roofing specialist in Pennsylvania, I always advise homeowners to work with local experts who know all building codes and safety measures. By reading this article, you can take steps to avoid costly roof damage, insurance claim issues, and legal disputes.

The Importance of Pennsylvania Re-Roofing Code R908 in Chapter 9

Pennsylvania re-roofing code R908 states a set of regulations that dictate the materials, methods of application, and structural requirements for re-covering or replacing an existing roof covering. Complying with this code ensures that homeowners maintain safe and reliable roof systems that meet the minimum design and construction standards.

R908.1 General: Requirements for Roof Covering Materials and Application

According to Section R908.1, the materials and methods used for re-covering or replacing an existing roof covering (asphalt shingles, metal panels, wood shakes, or tiles) must comply with the requirements specified in this chapter. This section outlines the necessary standards and specifications for homeowners and contractors. 

Exception 1: Positive Roof Drainage

In cases where the roof provides positive drainage, re-covering or replacing an existing roof covering is not required to meet the minimum design slope requirement. This exception accounts for roofs that have adequate roof drainage systems in place.

Exception 2: Secondary Drains or Scuppers

For roofs that provide positive drainage, the addition of secondary drains or scuppers, as mentioned in Section R903.4.1, is not necessary when re-covering or replacing an existing roof covering. This exception allows homeowners to avoid additional modifications if their existing roof already provides proper drainage.

R908.2 Structural and Construction Loads: Ensuring Roofing System Support

Section R908.2 emphasizes the importance of ensuring that the structural roof components can support the weight of the roof covering system, as well as any additional material and equipment loads encountered during the installation process. When selecting and installing new roofing materials, you must consider the roof's load-bearing capacity.

R908.3 Roof Replacement: Removal of Existing Layers of Roof Coverings

Roof replacement, as stated in Section R908.3, involves the complete removal of all existing layers of roof coverings down to the roof decking. This process ensures a clean and sound foundation for the new roof covering. However, there is an exception in cases where an ice barrier membrane or roofing underlayment adheres to the roof deck. In such situations, the existing ice barrier membrane can remain in place, covered by an additional layer of ice barrier membrane.

R908.3.1 Roof Re-Cover: Installation of New Roof Covering over an Existing One

Section R908.3.1 permits the installation of a new roof covering over the old one under certain conditions, which are as follows:

  • You need to follow the approved instructions provided by the roof covering manufacturer.
  • You can install new materials over old ones if you are using complete and separate roofing systems. For example, standing-seam metal roof systems, which can transmit the roof loads directly to the building's structural system without relying on the existing roofs and roof coverings for support.
  • You can install metal panel, metal shingle, concrete, and clay tile roof coverings over existing wood shake roofs, following the guidelines outlined in Section R908.4.
  • You can apply a new protective roof coating over an existing spray polyurethane foam roofing system without the need to remove the existing roof coverings.

R908.3.1.1 Roof Re-cover Not Allowed: Conditions for Disallowing Re-covering

Section R908.3.1.1 specifies conditions where roof re-covering is not allowed. Here’s what these conditions say:

  • When the existing roof or roof covering is water-soaked or has deteriorated, it is not suitable as a base for additional roofing.
  • If your old roof covering is made of slate, clay, cement, or asbestos-cement tile, it needs to be removed.
  • When an old roof has two or more layers of any roofing covering material, it needs to be replaced.

R908.4 Roof Re-Covering: Addressing Combustible Concealed Spaces

When applying a new roof covering over wood shingle or shake roofs, Section R908.4 requires the entire existing surface to be covered with materials such as gypsum board, mineral fiber, or glass fiber. This measure is necessary to address combustible concealed spaces that can pose fire hazards if left uncovered.

R908.5 Reinstallation of Materials: Guidelines for Slate, Clay, or Cement Tile

Section R908.5 permits the reinstallation of existing slate, clay, or cement tile, with the exception of damaged, cracked, or broken pieces. Additionally, any flashings, edgings, outlets, vents, or similar devices that are part of the roof assembly must be replaced if they are rusted, damaged, or deteriorated. Aggregate surfacing materials should not be reinstalled.

R908.6 Flashings: Construction and Installation Requirements

Section R908.6 emphasizes the importance of reconstructing flashings in accordance with the approved manufacturer's installation instructions. When installing bituminous materials on metal flashings, it is necessary to prime the metal before installation to ensure proper adhesion.

By following these regulations and working with knowledgeable professionals, homeowners can ensure the longevity, safety, and compliance of their roof systems, leading to peace of mind and protection for their homes.

If you are looking for a roof replacement service in Pennsylvania and want to learn more about the local codes and licensing requirements, we’ll be happy to guide you.

Free Consultation and Estimate on Re-Roofing in Pennsylvania

At McClellands Contracting and Roofing LLC, our team is proud to be a part of the Pennsylvania community. We’ve been working with the residents of Pittsburgh and the surrounding area for years, and are dedicated to helping fellow homeowners in our community with our roofing expertise and skills. If you are looking for a new roof that adheres to code and looks beautiful for years, you can trust our reliable and friendly professionals with flawless craftsmanship. Call us at (412) 353-5660, and we’ll be happy to help you with a free consultation and estimate on your roof replacement cost in Pennsylvania.


A.Permits are generally required for roof replacement in Pennsylvania when there are changes to the underlying structure of the building. If you are making modifications to the roof structure, such as adding or removing trusses or rafters, a permit is typically necessary. In certain areas like Pittsburgh, permits may also be required for changes to roof decks or sheathing.

A.The roof pitch code in PA is specified in Section R905 of the Pennsylvania residential re-roofing code. It requires a minimum design slope of one-quarter unit vertical in 12 units horizontal (2-percent slope) for roof coverings.

A.Class A and Class B roofing materials refer to fire resistance ratings for roof coverings. Class A materials have the highest fire resistance, while Class B materials have a slightly lower fire resistance rating. These ratings are determined based on specific tests and standards defined in building codes.

A.Pennsylvania uses the International Building Code (IBC) as its primary building code. However, the state may adopt and modify the code to meet its specific requirements. It is important to consult the local authorities or building departments for the exact version and amendments of the code in effect.

A.The most common roof type in Pennsylvania is the gable roof. Gable roofs have a simple triangular shape with two sloping sides that meet at a ridge, forming the gable. This style is popular due to its simplicity, versatility, and ability to shed water and snow effectively. Other common roof types in PA include hip roofs and gambrel roofs, depending on architectural style and personal preferences.

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