A recover board is a roofing board designed to provide a stable, durable surface when a new commercial roofing system is installed over an existing roof assembly. It is commonly used during roof recover projects, where the existing roof is retained rather than completely removed. A recover board can help separate the new roofing membrane from the older roof system while providing additional protection, stability, and, depending on the product, insulation or fire-resistance benefits.
The terms recover board and cover board are sometimes used interchangeably because some roofing boards can perform both functions. However, their intended applications can be different.
What Is a Recover Board?
A recover board is installed as part of a roof recover or re-roofing assembly, typically over an existing roof system. Instead of tearing the existing roof down to the structural deck, contractors can install an appropriate board over the existing assembly and then install the new roofing membrane above it.
The purpose is to create a suitable substrate for the new roof while helping protect the new membrane from irregularities, seams, fasteners, and other characteristics of the existing roof.
Recover boards are available in several materials, including high-density polyisocyanurate, gypsum, perlite, wood fiber, and other engineered roofing boards. Product selection depends on the existing roof, membrane type, attachment method, fire and wind requirements, and the manufacturer’s approved assembly.
A roof recover should only be considered when the existing roof is suitable for recovery. The roof should be evaluated for moisture, deterioration, structural integrity, drainage, and the number of existing roof layers before installation.
What Is a Cover Board?
A cover board is a relatively thin, durable board installed above roof insulation and below the roofing membrane. Its primary purpose is to protect the insulation and improve the performance and durability of the roofing assembly.
Cover boards can help resist punctures, impact from hail and foot traffic, moisture exposure, and other forms of damage. Depending on the material and assembly, a cover board may also contribute to fire resistance, wind uplift performance, and the strength of the membrane attachment surface.
Common cover board materials include gypsum, glass-mat gypsum, high-density polyiso, cementitious boards, perlite, and wood fiber.
Recover Board vs. Cover Board: What Is the Difference?
The simplest distinction is application and purpose:
| Recover Board | Cover Board |
|---|---|
| Primarily associated with roof recover applications | Primarily used to protect insulation and support the membrane |
| Commonly installed over an existing roof assembly | Usually installed above insulation |
| Creates a suitable substrate for a new roof system | Protects insulation from impact, traffic, moisture, and other damage |
| May provide insulation or other performance benefits | May provide fire, impact, and wind-uplift benefits |
| Product specifications determine whether it can also serve as a cover board | Many cover boards are not specifically approved for every recover application |
Importantly, the distinction is not always absolute. Some products are specifically manufactured and approved for use as both recover boards and cover boards. For example, certain high-density roofing boards are marketed for re-roof/recover applications while also functioning as insulation or cover boards.
Why Does the Difference Matter?
Choosing the correct board is important because a commercial roofing assembly must work as a complete system. The board, insulation, membrane, fasteners or adhesive, roof deck, and other components all need to be compatible.
A board that works well as a conventional cover board is not automatically approved for every roof recover application. Contractors should follow the roofing manufacturer’s specifications and applicable code, FM, UL, or other assembly requirements.
The Bottom Line
A recover board is generally intended to facilitate installation of a new roofing system over an existing roof, while a cover board is primarily designed to protect insulation and provide a durable substrate beneath the membrane. The two terms can overlap because some roofing boards are engineered and approved for both applications.
For commercial building owners, the right choice depends on the condition of the existing roof, the proposed membrane system, wind and fire requirements, insulation configuration, and manufacturer-approved assembly. A professional commercial roofing contractor should evaluate these factors before recommending a roof recover or full replacement.
Related Questions
- What is a fire-rated cover board and when is it required?
- Which cover board options are most common on Florida commercial roofs?
- What is the difference between a seam plate and a barbed plate?
- How does the fire rating differ between a recover and a new roof?
- How does FM treat an existing roof during a recover?
- What is gypsum roof board and what role does it play?
- What is the difference between a “roof assembly” and a “roof covering” in code language?
