G.F.R.C. (03490)

All our Glass Fiber Reinforced Concrete (G.F.R.C.) products are custom made for a particular project. G.F.R.C. is manufactured by hand-spraying a cement/sand slurry via a pump through a slurry spray gun. Attached to the gun is an air-powered Chopper gun that cuts the continuous glass fibers into approximately 1 ½" long pieces.

G.F.R.C. is available in:

Glass Fiber Reinforced Concrete (GFRC) is one of the most innovative construction materials available today and facilitates unprecedented opportunities for design.

GFRC boasts over 20 years of proven performance since alkali-resistant glass fibers were first developed in 1969.

GFRC is a portland cement-based composite with alkali-resistant glass fibers that are randomly dispersed throughout the product. The fibers serve a purpose similar to the reinforcing steel in reinforced concrete which is placed primarily in tensile stress areas.

Because the glass fibers add flexural, tensile and impact strengths, the resulting material allows the production of strong -- yet lightweight -- GFRC architectural cladding panels.

GFRC cladding panels are available as wall units, window wall units, spandrels, mullions and column covers. Custom designed in sizes to suit the modular planning of the building, their largest dimensions may be vertical or horizontal.

Versatile GFRC is also suitable for use as fascia panels, soffits, sun screens, mansard roofs and interior feature panels. GFRC cladding panels are capable of accepting and transferring wind and self-weight and their own inertial seismic loads to the building's load resisting system, but are not considered as vertical loadbearing components or as part of the lateral load-resisting system.

Unlike many other exterior wall systems, GFRC panels are normally delivered to the site with steel studs integrated into the panels. This avoids the time and expense of adding the studs later.

It is important in evaluating costs to realize that GFRC panels provide more than the exterior finish. The steel stud frame provides a surface for applying the interior finish, such as drywall, as well as the window frame. It also provides a cavity for installation of insulation, plus electrical, mechanical and telephone conduits. This decreases the floor space needed for these items and eliminates trade overlap problems. And, since insulation is applied between the studs, U-values as low as 0.04 are possible without adding to the wall thickness. The GFRC wall system can also be designed to hang outside the floor slab. As a result, the net rentable or usable floor space can be increased which can appreciably affect the economics of a multi-story project.

The low weight of GFRC panels decreases superimposed loads on the building's structural framing and foundation, providing potential savings in multistory construction and in areas with poor supporting soil. Its light weight also makes it ideal for use on low-rise frame buildings where heavier cladding systems would increase the size of framing members required.

Further savings can be achieved by using less expensive fastening hardware due to the panel's lighter weight.

The light weight of GFRC panels allows the contractor to quickly and efficiently erect panels even in hard-toreach areas with smaller, less expensive cranes.

The reduced construction time also results in faster enclosure of the building, allowing quicker access by other trades. This faster completion time reduces interim financing costs, often resulting in earlier cash flow.

GFRC is ideal for building rehabilitation or renovation projects. Its light weight minimizes the load added to the existing structure. Its design flexibility in color, texture, pattern and surface finish allows it to blend with other construction material Exact replicas of original ornamental work from landmark and other historic buildings can be made of GFRC.

And, because GFRC is inorganic and does not contain materials that will burn or produce noxious gases, it does not add to the fire load of a building.

GFRC systems can be designed to provide the various degrees of fire resistance that may be required by building codes, insurance companies and other authorities.

GFRC allows the architect great flexibility in designing the most visible element of a structure - its cladding.

The variety of sculptural shapes made possible through the GFRC manufacturing process enables a wide range of creative architectural design.

The designer can choose from deep reveals to complex rectilinear and curvilinear shapes, such as short radius curves, wide sweeping arcs or 90-degree angles.

The degree of such complex shaping has minimal effect on the cost of the panel due to GFRC's inherent design flexibility. Optimum economy occurs, however, when reuse of forms is maximized with product repetition.

The sculptured shapes that are possible with GFRC window wall panels allows for the design of many types of shading devices for window areas, including vertical and horizontal sunshades. For example, profiled window wall units can form deeply recessed window frames that provide a high degree of sun shading and minimal solar heat gain without reducing natural light and view.

GFRC panels can be produced in many colors or textures. It is not only compatible with all structural systems, but can also be designed to harmonize with all other materials.

GFRC can be easily produced to match a granite or limestone facing; it can even be made to resemble a metal panel or match ornate terra cotta.

A wide variety of different aggregate colors can be formulated in the face mix. Panels can be produced with a ?- to ½-inch face mix with decorative aggregates. The aggregate may be exposed by retarders, sand or abrasive blasting; acid etching, or honing and polishing to produce the desired effect. Light, medium or deep exposure of aggregates is possible.

The cement matrix also offers a wide choice of color variations through the use of grey, white or buff-colored portland cements or through the use of color pigments. If deeper colors are required, concrete coatings or stains can be applied for an even wider variety of color options.

A smooth, off-the-form finish may be the most economical, but color uniformity of grey, buff or pigmented surfaces may be difficult to achieve.

The aesthetic limitations of smooth GFRC can be solved by the shading and depth provided by creating profiled surfaces, such as fluted, sculptured or board finishes; subdividing the panel into smaller surface areas; by using white cement, or by use of applied coatings.

A variety of attractive patterns and surface textures can be achieved by casting the panels against form liners. The fine matrix of GFRC allows production of even delicately detailed surface patterns in low relief at a reasonable cost. A form liner can also make smooth surfaces appear more uniform.

Different shapes and colors of natural stone veneers (such as limestone, marble or granite in narrow strips, small squares and rectangles or regular-sized ashlar pieces) may also be used in creating an almost infinite number of patterns. Clay products, such as veneerthickness brick, facing tile and architectural terra cotta (ceramic veneer), may also be bonded directly to GFRC, as may mosaics of marble and ceramic.

Maintenance and weathering of the panels will depend largely on its surface finish and local atmospheric pollution. The shape and surface features of the panel will dictate which way water will drain off and to what degree the panel will be self cleaning. It's a distinct design advantage that the architect can choose the shapes, textures and details of GFRC to mitigate the effects of weathering.

GFRC is manufactured by hand - spraying a cement/sand slurry and glass fibers into forms of the desired shape and size.

The cement/sand slurry is fed via a pump through a slurry spray gun. Attached to the slurry spray gun is an airpowered chopper gun that cuts the continuous glass fiber strands into approximately 1½-inch-long pieces. The chopped fiber strands and the cement/sand slurry are simultaneously propelled onto the form's surface. (A face coat of only the cement/sand slurry may be sprayed on first to provide cover for the glass fibers on the finished face.)

Several layers of slurry and glass fibers are deposited. Each layer is compacted with hand rollers, until the required panel thickness, usually ½ inch, is reached. After initial curing, the panel is removed from the form for final curing.

GFRC panels can be produced with or without a face mix of conventional concrete with decorative aggregates. In either case, the cementitious material produces a durable, lightweight wall for the structure. With a face mix, GFRC cladding panels are indistinguishable in exterior appearance from conventional concrete panels.

Unless the panel has a functionally strengthening shape, GFRC properties dictate the use of stiffeners on panels of any appreciable size.

Stiffeners may be prefabricated, plant-attached steel studs or structural tubes, or integral ribs formed on the back of the panel by overspraying hidden rib formers, such as expanded polystyrene strips or adding an upstanding single skin rib on the back of the panel.

Either method stiffens the panel and provides a means for connection to the supporting structure. The steel panel frame is usually the more economical and preferred method for stiffening, except where exposure to the weather or complex shapes dictate the use of integral ribs.

To assure a consistent, uniform manufacturing process, Durastone employs strict quality control procedures, such as materials testing, testing during fabrication and testing of the cured composite.

One of the greatest benefits of designing with GFRC is that Durastone is prepared to masterfully execute your concepts, equipped with an intimate knowledge of GFRC technology and the design characteristics of the material. Durastone can recommend the most cost-efficient system, assist in the design of fastening devices and in determining erection procedures.

As is the case with other building materials, to achieve a fully satisfactory GFRC panel building requires advance planning and close coordination between Durastone, the erector and general contractor. Following are some of the guidelines you should consider:

Samples should be developed as a means of translating design concepts into realistic production requirements.

It is advisable to avoid thin projections whenever possible, use rounded comers and incorporate chamfers at inside comers of the form due to the possibility of fiber bridging.

With GFRC, you can design deep reveals and curvilinear as well as rectilinear panels.

In establishing the shape, consider the draft required to strip the unit from the form and to achieve a specific finish. Generally the draft or slope to vertical walls for ease of stripping should be a minimum of I inch in 8 inches.

When the surface of a GFRC panel has two or more different mixes or finishes, a demarcation feature is necessary.

Carefully calculate the weight savings allowed by lightweight GFRC panels and factor that reduction back into the structural design. Exposed aggregate facings can increase the weight of a panel, which must be allowed for in the design of the structure.

During panel erection, priority is given to exterior panel alignment. This may result in the interior stud face not being in a true plane. Panel design usually prevents stud or tube spacing from being coordinated with interior drywall modules. Therefore, it is recommended that, if the studs are to receive interior drywall or similar treatment, drywall be mounted on shimmed transverse furring channels rather than directly to the studs.

Connection details for each project should be standardized. Repetition of the same connection improves quality control and structural performance. Furthermore, standardization of details facilitates selection and shipment of connection items with fewer delays and added economies.

Windows should be attached directly to the head and sill tracks of the panel frame (or to a separate framing system) with only sealant contact to the GFRC.

The design of joints between GFRC panels is an integral part of the total wall design. Requirements for joints should be assessed with respect to both performance and cost. joint width should not be chosen for reasons of appearance alone, but must relate to panel size and building tolerances, anticipated movement, joint materials and adjacent surfaces. The required width of the joint is determined by the temperature extremes anticipated at the site location, the movement capability of the sealant to be used, the temperature at which the sealant is initially applied, panel size and fabrication tolerance of the GFRC units. Minimum design joint width should be ½ inch, 3/4 inch preferred, and minimum panel design return for the joint should be 1½ inches.

Versatility...light weight... money savings ... unlimited diversity in color, form and texture. These are the advantages GFRC provides for the designer/architect.

For the owner and tenant, GFRC provides durability, fire resistance, sound attenuation, energy conservation and general superior properties inherent in the material.

Call Durastone in the early design stages and throughout the development of the contract documents.

Utilize Durastone's extensive knowledge in exploring how to best turn your concepts into practical, functional components on your next project.

Then capitalize on Durastone’s experience in aiding you to design for optimum quality and maximum economy with minimum costs.