Pre-engineered metal buildings systems are used on 69% of the low-rise nonresidential buildings in the United States, and most of these buildings do not have masonry. To preserve remaining market share, the masonry industry is seeking ways to increase the use of concrete masonry units (CMUs) in conjunction with metal building systems.
But by only focusing on new construction, block producers may be missing an even larger opportunity in the metal building arena: the aftermarket for upgrading existing metal buildings.
Reasons to upgrade to block
Even the highest-quality metal wall systems are prone to paint fading, corrosion and impact damage. With age, the gaskets and caulks used to seal panels against air and water penetration can lose resiliency or adhesion and permit leaks. Many existing metal walls were erected before current energy conservation standards were in place and may no longer provide optimum insulation. And whatever insulation was installed may have lost effectiveness because the vinyl vapor barriers used to retain fiberglass insulation are easily punctured or torn.
Also, CMU walls can upgrade a metal building in a number of ways, including enhanced fire resistance, noise isolation, energy conservation, durability and security. CMU walls can also improve the appearance of a metal building.
Sales and marketing
However, building with masonry usually costs significantly more than metal panel replacement. Block producers and masonry contractors must work together to sell building owners on the life-cycle cost advantages of masonry and the other benefits of CMU construction. Begin by taking note of existing metal buildings in your community. Where are they, who owns them, and what is their condition? Watch for metal buildings that go up for sale, change ownership or convert from one occupancy to another, or for metal building owners who hire an architect.
Another marketing tactic is for CMU producers and masons to form alliances with metal building dealers, most of whom are general contractors. Many successful metal dealers are likely to know which former clients are considering renovations.
Technical considerations for block-to-metal building sales
Here are some special areas of concern that producers should know about when working their masonry contractor to sell a composite masonry/steel building to the owner.
Partial Height. Partial height walls or wainscots provide increased security and damage resistance to the lower reaches of a wall. A cantilevered wainscot can be erected independently of the existing metal building structure. Or, a wainscot can span horizontally between a metal frame's columns, vertically between the ground and a girt (a horizontal framing member located between the top and bottom of a metal building wall) or vertically between the ground and a beam constructed in the top course of the masonry and spanning between metal building columns.
Full Height. Full height walls can span either horizontally or vertically. Metal buildings typically have horizontal framing members to support wall panels: an eave beam at the top of the wall resists horizontal loads in the wall panels and vertical loads in the roof, and girts are spaced between the eave and the base of a wall to resist lateral loads. In vertical span conditions, the adequacy of the existing girts and eave beams must be examined before using them to support out-of-plane loads. Special flashings may be required to seal the existing roof to the new masonry wall.
Parapet Walls.The existing roof may have to be modified to create internal gutters and flashings.
Movement. MIf a masonry wall is to be attached to the metal building frame, the base of the wall should be designed as a hinge and adequate movement control joints must be located between intersecting walls. See NCMA guidelines for suggested details.
Existing panels. Removing existing wall panels generally simplifies anchorage of the masonry to the existing structure. Removing the panels also allows the new CMU to be used as an attractive interior finish surface. In some cases, however, it may be desirable to leave the existing panels in place so the masonry can be erected without exposing the building interior to weather.
Foundations. Since lightweight metal wall panels are typically installed without footings, footings will have to be installed before a masonry wall is erected. An alternative is to construct reinforced beams in the CMU wall which span between the existing column footings and, if necessary, new spot footings between column lines.
Seismic. Due to the greater mass of a masonry wall compared to a metal panel, an existing metal building frame may not be able to resist the horizontal thrust created by a masonry wall during an earthquake.
Inspection and design. As in any building renovation, qualified professionals should evaluate the condition of the existing structure.
Keywords: masonry block, marketing, metal building, concrete masonry unit