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What is Stromberg GFRC?

GFRC stands for glass fiber reinforced concrete. GFRC is made from portland cement, fine crushed natural stone, and manufactured or natural sand and reinforced with special glass fibers. Iron oxides may be added for color.
In Stromberg GFRC, special proprietary polymers are used to improve performance and the exclusive recipe and system of mixing and production produces some of the strongest and most durable GFRC in the world. Tested and proven both in the lab and in the outside world for over 25 years.

What products are produced from GFRC?

Our GFRC products can be broadly divided into two types:

GFRC architectural features: Columns, balustrade, trim, ornament, copings, sills, banding, door and window surrounds, domes, bases, etc.
GFRC panels and cladding: Non-structural wall panels, window units, spandrel panels, soffits, sunscreens, fascia panels, etc.
GFRC Site Amenities: Planters, fountains, bollards, benches, landscape elements.
Special Applications: Defense applications, utilitarian applications, displays.

What are the benefits of Stromberg GFRC Cladding panels?

Reduced weight saves structure, foundation and time.
Outstanding durability, including fire, salt water, freeze thaw and impact resistance.
Unlimited aesthetic choices and freedom of design.
Peace of mind-factory fabrication enables consistent quality control.
Fast-track construction-faster to erect, fewer uncontrollable delays, lower costs. (Up to five times faster than field fabrication)
Excellent thermal efficiency and weather tightness which can reduce energy costs.

What are the advantages of the reduced weight with GFRC?

The benefits of weight savings with GFRC can include:

Less of a load on the structure and that can mean dramatic savings in structural steel, building foundation, construction time, etc.
Faster and less expensive installation with lighter equipment and fewer men
Less environmental impact from using less material
Thinner skin means more room for more insulation for greater energy savings
Reduced seismic load

What is the weight difference between GFRC and precast concrete?

GFRC weighs between 6 and 14 lbs per square foot vs. 70 to 80 lbs for a 6" precast concrete panel.

How much design freedom can I have with GFRC?

If you dream we can build it. Most other building products are more "standardized" in nature but all of our GFRC is either custom or customized. With Stromberg GFRC you can select or invent the shape, color, texture and size you want. Stromberg GFRC offers unlimited aesthetic options and excellent flexibility of design.

Can your GFRC panels be curved?

Yes. (They can also be cast with waves, twists, domes, geometric patterns, sculpted, etc).

What are the standard sizes for Stromberg GFRC panels?

GFRC cladding panels are custom made to meet your needs, so there is no standard size. Maximum size is controlled by shipping and handling considerations. As a general rule, panels of around 8'6" by 14' are a good practical size but panels up to 14' by 28' + can be produced and shipped with a wide load permit. Maximum panel sizes will depend upon the thickness and composition of the GFRC panel (i.e. 6" stud backup vs. 3 5/8". A thinner panel depth limits the size).

What colors and finishes are available with your GFRC panels?

There is a huge range of choices and options. The standard finish on a GFRC panel is a lightly textured limestone type surface. The surface can also be smooth, rough textured, fossil stone, glazed terra cotta, exposed aggregate or wood grain. GFRC can have the appearance of a variety of natural building stones including limestone, granite, travertine, slate, or marble

Are custom colors available?

Yes. We can provide virtually any color.

Are colors cast in?

Yes, they can be. Generally a color is cast in and integral to the face mix of the GFRC.

Can your GFRC panels be painted in-the-field?

Yes, the panels can be field painted if desired.

Can you have multiple colors or texture on the same GFRC panel?

Yes. You have a wide range of choices with color and texture and we can fabricate panels with multiple colors and textures on one panel.

Can Stromberg GFRC cladding panels be factory insulated?

We can pre-insulate the GFRC panels with foam, rock wool or fiberglass. The added R-value provided by the insulation (R-8 or more depending on panel depth) can improve the thermal efficiency of the structure, leading to corresponding reductions in energy use. If foam insulation is requested, one of three types of rigid foam insulation board can be used: EPS-Expanded Polystyrene, XPS-Extruded Polystyrene, or ISO-Polyisocyanurate. Each type of foam has unique properties of R-Value, density and cost.

How are GFRC panels made?

First molds are made. These are specially created reverse images of the product being produced. Molds may be plastic, rubber, fiberglass or wood. Once the mold is made the panels are produced by hand spraying or casting a special mix of cement/sand and chopped glass fibers into molds.

GFRC panels are cast face down. An integrally colored face mix, is sprayed into the mold first. Then several layers of the mix and special glass fibers are sprayed in place. As they are sprayed up, each GFRC layer is compacted with rollers or brushes to compact and consolidate the layer and form a compact composite.

On panels that receive a steel stud frame, a light gauge steel stud & track frame is positioned over the back of the freshly cast panel and is connected to the back of the GFRC skin via L-shaped "flex anchors" embedded in GFRC bonding pads.

Once the GFRC has hardened it is removed from the mold and "cured" until it reaches its design strength.

Why and when are steel stud frames and flex anchors used?

On large panels the GFRC serves as the aesthetic face and the steel stud backup adds rigidity. At the construction site the steel frames are welded or bolted into place. The stud cavity can be used for insulation, electrical wiring and mechanical passages. Flex anchors as the name implies are designed to flex and they allow the GFRC skin to expand and contract independently of the light gauge steel frame to avoid cracking.

Can panels be made without steel frames?

Yes. For some applications where steel studs are not desired, integral GFRC ribs in the GFRC panel can serve the same purpose.

What services does Stromberg GFRC offer designers and builders?

We provide extensive design and detailing assistance as well as budget estimates and GFRC specification assistance up front. Shop drawings include connection detailing, erection planning and layout. Erection and other services are also available to ensure a high quality, hassle-free installation.

Can Stromberg GFRC be used for recladding an existing building?

Definitely. Lightweight, strong and durable GFRC is ideal for re-cladding existing buildings. Often we can install GFRC directly over the existing cladding. Deteriorating masonry, stucco, terra cotta or concrete can be often be covered with GFRC panels without the need to remove the existing materials. Lightweight GFRC places only a minor load on the structure and generally requires no additional reinforcing. These re claddings can often take place from the exterior of the building only with very minimal disturbance to the tenants. This saves time, keeps the building occupied and generating income and breaths new life into an old building.

What about historic terra cotta replacement in GFRC?

Stromberg has a great deal of experience in historic architectural terra cotta replacement with GFRC. Projects have included the largest terra cotta restoration in Michigan history, the Parkland Hospital (named "Save of the Year" by the Dallas Morning News) and many others across the USA. Stromberg GFRC can reproduce the look and feel of historic terra cotta in a lighter, stronger, more durable and easier to install material. Terra cotta columns, cornice, friezes, balustrade and copings have all been reproduced on several award winning restoration projects.

Do you provide all the accessories for installing GFRC cladding panel system?

Yes we can. The system is available either as a complete package or as GFRC panels only.
With a complete package, we can provide the materials that are required (i.e. fasteners, clips, sealant, etc.) to complete the GFRC installation.

What types of fasteners can be used with GFRC panels?

There are two types of GFRC panels. One with steel stud backup and one without, depending on size and application. The larger stud backed panels are attached with clips and bolts or welding. The smaller panels are attached with clips and hidden screws.

What types of sealant may be used with your GFRC panels?

We recommend GE and Dow silicones for most applications.

Do you have approved fabricators and/or installers?

Yes. We have certified installers or you can use your own installer.

What if I choose to deviate from the installation guidelines?

Our recommended guidelines for installation are based upon some 25 + years of experience. We also recognize that every job is different. We are here to help. Contact our technical staff at (903) 454-0904 or [email protected] with any special requirements or conditions.

What types of sheathing and building substrates can be used with GFRC?

Smaller GFRC In general, smaller GFRC elements and panels are attached with screws over a nailable substrate (i.e. plywood) with a moisture barrier. GFRC may also be placed over a non-nailable substrate such as DensGlass®. When using a non-nailable substrate, the GFRC must not be attached to the substrate but fastened directly through to the stud framing.
Large GFRC cladding panels GFRC panels with integral stud framing is used where a floor to floor cladding panel is required. The light gauge steel frame is the support for the GFRC. The stud cavity can be insulated and the interior side receives hat channel furring and gypsum board.

Can GFRC panels be used in a structural application?

Yes and No. Our GFRC panels and elements are designed to be used as cladding only. However, GFRC with integral ribs or steel studs may be considered part of the structural wall assembly if it is engineered. Contact our technical staff for more information.

Can GFRC panels be used in a roof application?

Yes. Roof domes, cupolas, parapets and cladding panels are possible but must be properly detailed. The roof must have a moisture barrier other than the GFRC.

What about the durability of GFRC in marine environments?

Stromberg Super GFRC has been used under sea water for years without corrosion. Conventional concrete relies on rebar or steel mesh face reinforcing. Steel mesh can have problems with rust and corrosion if the concrete cover is too thin. This is especially a problem in coastal areas and where de icing salts are used. If the steel reinforcement in concrete corrodes, it more than doubles in volume and causes cracking or spalling from "rust jacking". It may also cause unsightly rust staining. Stromberg Super GFRC relies on fibers that are 4 times stronger than steel and never rust. Near the ocean, in the ocean, under the ocean, Stromberg GFRC lasts.

What maintenance and/or cleaning is needed for GFRC?

Minimal. As with precast concrete or glass, joints will need to be inspected and re-caulked when necessary. Depending on panel type and location, an occasional wash down to remove dust may be appropriate. Different finishes and textures may require more or less maintenance. In the "touch zone" hand prints can be removed with water. Anti graffiti sealers can be factory applied or field applied. We provide guidelines and recommendations for panel cleaning on request.

What about Hurricanes and high wind, does Stromberg GFRC hold up?

In lab testing, modified Stromberg GFRC panels have survived the large missile impact test (the impact of a 27 lb. 2x4" stud propelled into it at 120 mph).
In the real world, Stromberg GFRC panels have survived multiple hurricanes in the Bahamas (including a category 5 hurricane) as well as hurricanes in New Orleans, Miami and Houston. Hurricanes have struck the 23 story Atlantis Resort in the Bahamasmultiple times and the Stromberg GFRC suffered no damage. The GFRC cladding and parapet panels on Houston's Galleria II tower were undamaged by hurricane Ike.

What about earthquakes and GFRC?

The lightweight and resilient nature of GFRC allows it to function very well in seismic areas.

Does the GFRC need a factory applied sealant?

That depends on the project. . Sealing is sometimes desirable to retain the pristine look of GFRC, especially around dirt, moisture and handling. Unsealed, GFRC will naturally age and in shaded and damp locations, lichens and moss can form. On darker colors of GFRC, sealants can help to minimize efflorescence. Anti graffiti sealers can be factory applied or field applied.

How long does GFRC last?

Stromberg GFRC has physical properties that are the same or stronger than most dimensional building stones or architectural precast concrete. Properly installed GFRC can result in an architectural project of enduring beauty to be enjoyed for decades to come.

Is Stromberg GFRC durable in cold northern climates?

Yes, very durable.
Freeze thaw resistance varies depending upon the mix design, color and aggregate but in harsh laboratory freeze-thaw tests, samples endured 300 cycles of saturated freeze thaw (equivalent to 50 years in a typical northern US city) with minimal flaking, while the control samples of unreinforced mortar were severely damaged after only 200 cycles.

How is GFRC shipped?

GFRC generally ships by dedicated air ride trucks. On very small jobs we sometimes use a common carrier. If the order is less than a truck load we can sometimes pool orders for a less than truckload rate. We will figure the most cost effective method of shipping your order.

Is shipping GFRC panels across country economical?

Yes. We ship GFRC anywhere in the USA as well as around the world. GFRC panels are relatively lightweight. When shipping GFRC panels with light guage steel backup frames a truckload is generally between 1,200 to 2,200 square feet of GFRC vs. about 350 to 400 square feet for cast stone or architectural precast concrete panels. The difference allows us to supply GFRC economically to all parts of the USA (including Hawaii and Alaska) as well as Canada, Mexico and the Caribbean. Europe, Africa, the Middle East and Asia are supplied by containerized shipments.

Where can I purchase GFRC panels and products?

We sell direct. Contact us, we provide product information, customer support, technical service, specification and detailing assistance and samples. To speak to a representative, call us at (903) 454-0904 or click here ...

What is the lead time for your GFRC panels?

That depends. Normally the lead time for manufacturing for most products is 4 to 12 weeks from approvals. Actual lead time will vary depending upon the models and molds, order size, custom colors or special shapes, location of project, etc.

Will someone come to the job site to take measurements?

Generally no. The Stromberg shop drawings are extensive and well detailed and allow for field checking by others.

What is the price of Stromberg GFRC cladding panels?

Depending on design, Stromberg GFRC panels are generally priced less than conventional precast or other curtain-wall systems such as brick veneer masonry or brick veneer stud walls. And on complex shapes the price difference becomes even more substantial. After factoring in reductions to structural support requirements and potential energy and operating savings, along with faster and less costly installation, Stromberg GFRC Cladding Panels save you money up front and can help save you money over time.

Where do we start?

Call us or email we are here to help