What Is a 5-Ply Roof?

Roof Felt

• A number of roof felt types can be used with a 5-ply roof. Fiberglass impregnated felt is tougher and less prone to tears. All of the roofing felts contain asphalt and are often known as tar paper. The base ply of the roof felt is attached to the roof deck with nails or staples while subsequent layers of roof felt are held in place by the asphalt.

Asphalt

• Several types of asphalt can be used in built-up roofs. Some include fibers that provide additional strength to the roofing material. The asphalt is heated in large vats and applied with mops to the roof while its hot. Because of the heating requirements of the asphalt BUR, application is commonly done by roofing professionals.

Number of Plies

• Built-up roofing systems can include three, four or five plies. Each layer of material adds cost to the roofing project but extends the viable life of the roofing system. A 3-ply roof may be warranted for 15 years while a 4-ply roof might be expected to last 20 years. The 5-ply roof can have a 25-year effective life. The actual warranty will vary with the roofing contractor and the actual durability of the roof varies with the weather conditions.

Top Surface

• The top layer of a built-up roof often is covered with gravel or crushed stone. The stone material serves as a protective layer over the top coat of asphalt. If loose crushed stone is not an option, a special top layer of roofing felt including a fine layer of aggregate or stones can be substituted.