OSB Manufacturing Plant Construction Continues

Work continues in Corrigan on an oriented strand board (OSB) manufacturing plant, the first such facility in the Lone Star State for RoyOMartin. Due to open in fall 2017, the plant represents a $280 million investment, is situated on 158 acres, and adds 165 direct jobs. The Corrigan OSB LLC greenfield OSB plant will ship products throughout the U.S. OSB is primarily used for roof and wall sheathing in construction.

Company officials and the East Texas community celebrated the grand opening of the plant’s administration building, which marked the beginning of the transition from a construction site to a fully operational facility. Construction began in July 2015 and is nearly halfway complete. About 30 employees have been hired to date. Corrigan OSB LLC will complement RoyOMartin’s other OSB mill in Oakdale, La., in manufacturing RoyOMartin-branded OSB products that include Eclipse OSB Radiant Barrier, Eclipse OSB Wall System, TuffStrand, WindBrace, and Structwall.

“We believe East Texans share our passion for excellence and experience,” says Roy O. Martin III, president, CEO, and CFO of RoyOMartin. “We have sold into the Texas market for a long time, and now we look forward to becoming a proactive partner in the community.”

Named a 2016 Manufacturer of the Year by the Louisiana Association of Business and Industry, RoyOMartin brings more than jobs to the region. The company has also earned accolades for safety and employee development programs, including WoodWorks and RoyOMartin University. The former is a program in local high schools that trains students for careers in the wood products industry. The latter is an on-site training program that provides employees a perspective on the business and prepares them for advancement within the company. It also aims to teach behaviors and instill principles that make graduates valued participants in the communities in which they live.

“We’ll extend our philosophy of being ‘employer of choice’ and ‘vendor of choice’ to the region, while maintaining the stability of a company committed to its stakeholders,” Martin adds.

Cover Boards: The Membrane and Insulation Protector

Continuing on our roof system component analysis—after discussion of the roof deck, substrate board, vapor retarders and insulation—we now have worked our way up to the cover board. For the purpose of this discussion, the cover board is defined as the board placed upon the insulation as the final substrate to which the roof cover will be placed.

The purpose of the cover board is multifaceted; it can include:

    Insulation Protection: Placed to protect the thermal layer from the often deleterious effects of repeated foot traffic, which can result in insulation crushing, loss of roof-cover adhesive, inability to resist wind uplift and mechanical- fastener puncture through the membrane.

    Asphaltic core boards are very flexible and will conform to irregular surfaces and offsets without fracture. Here crews work to install the cover board in bead-foam adhesive in preparation for the three-ply modified bitumen roof cover. PHOTO: Clark Roofing

    Asphaltic core boards are very flexible and will conform to irregular
    surfaces and offsets without fracture. Here crews work to install the cover board in bead-foam adhesive in preparation for the three-ply modified bitumen roof cover. PHOTO: Clark Roofing

    Enhanced Roof-cover Adhesion: Cover boards can enhance the bond between the roof cover to the substrate.

    Enhanced Resistance to Wind Uplift: Cover boards and their ability to enhance the bond of the roof cover to the underlying substrate can result in an increased wind-uplift rating above and beyond that which can be provided with organic-faced insulations. They reduce the possible effects of facer-sheet delamination.

    Enhanced Fire Resistance: Many cover boards will enhance the fire resistance of the assembly.

    Hail Protection: Numerous studies show the value of cover boards in enhancing a roof cover’s ability to resist damage by hail.

    Provides Separation: A cover board provides separation between a roof cover and insulation that may not be compatible or the attachment adhesive of the roof membrane is not compatible with the insulation.

    Reduces Thermal Shorts (Energy Loss): Thermal insulation is often attached to the roof deck with mechanical fasteners, which results in conductive heat loss, up to 7 percent according to the Rosemont, Ill.-based National Roofing Contractors Association. This is a large value when some roof covers, which utilize mechanical attachment, purport to provide energy savings. Furthermore, when only one layer of insulation is used (a cardinal sin in my opinion) an additional 7 to 8 percent energy loss can occur. Placing a cover board above mechanically attached insulation and/or a single layer of insulation will enhance the energy performance of the roof system.

    Enhanced Roof-system Performance: I firmly believe the use of a roof cover board in a roof system improves the overall performance of the roof system and increases the probability of the roof attaining a long-term service life, which is the essence of sustainability. NRCA agrees; the organization recommends the use of cover boards in all low-slope assemblies.

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Roof Decks: Don’t Underestimate the Backbone of the Roof System

NOTE: This article is intended to provide general information while conveying the importance of the roof deck as an integral part of a roof system. Additional information about specific effects and concerns in regard to roofing can be found in The NRCA Roofing and Waterproofing Manual and various roof-cover manufacturers’ design guides.

Wood plank decks can provide a dramatic exposed roof deck.

Wood plank decks can provide a dramatic exposed roof deck.

The roof deck is the backbone and an integral component of all roofing systems. Its main function is to provide structural support for the roof system and, therefore, is a building element that needs to be designed by a licensed design professional because proper support of the roofing above is critical to the roof system’s success.

Roof decks also add thermal performance and fire resistance and ratings, provide slope for drainage and enhance wind-uplift performance. They must accommodate building movement and often determine the attachment method of the vapor retarder, insulation and membrane.

Roof Deck Types

There are many types of roof decks being installed today:

  • Steel
  • Precast concrete panel
  • Structural concrete
  • Cementitious wood fiber
  • Wood planking
  • Plywood/OSB
  • Poured gypsum

Some decks are covered with topping fills that become the base for the roof system and may also be an integral structural component:

  • Concrete
  • Lightweight insulation concrete topping
  • Lightweight aggregate concrete topping

Other deck toppings are available, such as poured gypsum and lightweight concrete with integral insulation, but these are considered substrate covers and not roof decks.

The most prevalent roof deck in the U.S. for commercial buildings is steel. On the West Coast, plywood/OSB is very popular. In addition to the roof decks already mentioned, in the course of roof-replacement work the designer may come in contact with the following:

While the “plate” test is not a preferred method, it can quickly and inexpensively give an indication of retained moisture in lightweight aggregate concrete roof deck covers.

While the “plate” test is not a preferred method, it can quickly and inexpensively
give an indication of retained moisture in lightweight aggregate
concrete roof deck covers.

  • Book tile
  • Lightweight precast concrete planks
  • Precast gypsum planks
  • Transite

Collaboration with the Structural Engineer

Because a roof deck is the foundation for the roof system, the designer needs to coordinate the roof system design requirements for the roof deck with the structural engineer to ensure the performance of the roof system. For example, the roof deck may need to extend to the roof edge. In this example, the roof deck may not need to extend to the roof edge for structural concerns but is needed to support the roof system; the roof designer must address this. If the roof deck is structurally sloped, the designer and engineer must determine whether the low point is a potential drain location. Are there steel beams in the way of the drain location? The roof deck must be attached to the structure to prevent uplift. And the designer and engineer must determine what the deflection of the roof-deck span may be between structural supports. For example, steel deck is sometimes installed with spans of 7 feet between joists and flexes (deflects) under foot traffic. This typically is not a good condition onto which a ridged roof system, such as a bituminous one, should be installed. It cannot be expected to accommodate such deflection. PHOTOS: Hutchinson Design Group Ltd. [Read more…]