FREE QUOTE REQUEST
Custom Arches and Keystones
Who Is This Solution For
Engineered architectural arches and keystone elements for facades and interiors
Designed to form arched openings, niches, and decorative portals without transferring structural loads to the building. The products serve an architectural and compositional function, but are not load-bearing elements.
Arches & keystones are made exclusively from EPS foam with a density of 1.0–1.5 lb/ft³, depending on the project scale.
EPS is used as a lightweight molding core and is always covered with a protective Hard Coat Polyurea coating. This formula provides:
- impact strength;
- moisture resistance;
- UV stability;
- compensation for micro-movements of the base;
- geometric stability during temperature fluctuations.
How We Work
How to Order from Royal Foam
Step 1. Adaptation
If you have a finished design, we adapt it for production and installation, preserving every detail.
Step 2. Define your vision
Capture a clear picture of the client’s ideas before moving to design and rendering.
Step 3. Plan specifications
Outline measurements, production methods, and finalize materials, components, and finishes.
Step 4. Production and assistance with logistics
Step 1. Define your vision
The aim of this step is to capture a precise picture of the client’s vision before proceeding to technical design and visual rendering.
Step 2. Plan specifications
During this phase, we define the specifications, production methods, and measurements, while finalizing the look by selecting materials, elements, and finishes.
Step 4. Production and assistance with logistics
Areas We Serve
We proudly serve clients across the United States,
including major cities such as
· Jacksonville · Orlando · Miami · Atlanta · Dallas · Los Angeles · New York City · Chicago · Washington · San Francisco ·
Companies We Serve
Testimonials
Been using Royal Foam for about 2 years now on various projects. Their CNC cutting capabilities mean I can get literally any design my clients wish, especially when it comes to complex arch structures. The EPS material is a real treasure for exterior work, cause it’s lightweight, weather-resistant, and looks absolutely authentic once painted. The turnaround time is also inspiring. As a rule, parts are manufactured within a couple of weeks at most. It's great when projects don't get stuck.
Phillip Cameron
We wanted to make our brick house fancier and decided on decorative arches over the windows. Honestly, I wasn't sure about foam at first, but the guys at Royal Foam explained the properties and installation details to me very clearly (btw, the consultation was free). The keystone details are so realistic - our neighbors think we added real cast stone, lol. Best part is they handle the Texas heat perfectly, don’t deform, and don’t fade even after a whole summer.
Raymond O'Neal
After installing an arch from Royal Foam not only the look has improved but also my home has become a lot more spacious. I suggest and thank Royal Foam. I will contact again to Royal foam for my new arch work at my home. Designs are very good and finishing is also good.
Amy Corey
If you're not using EPS for architectural details yet, you're behind the curve. Royal Foam has the best quality material I've found, and their range of equipment means they can produce any shape, even super complex ones. Just completed a luxury home in Florida with their custom arches and keystones - client thought it was real limestone until I told them otherwise.
Thomas Welsh
Frequently Asked Questions
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Yes, even in non-standard climatic conditions. EPS architectural arches with a polyurea coating retain their appearance for more than 25 years, whether in coastal areas of Florida or northern regions with temperature fluctuations. The coating protects the surface against moisture, UV rays, extreme temperatures (from -40°F to 180°F), and salt exposure.
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Sure, this is one of our company's core capabilities. Thanks to CNC technology, we can create unique geometric shapes with perfect precision, whether it's elliptical arches with a radius of 15 feet or four-centered Tudor-style structures. Custom orders increase the manufacturing time by 1-2 weeks with a minimal additional charge.
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Properly installed decorative EPS arches will perform for more than 25 years when used outdoors. Indoor installations can last virtually indefinitely, as they are not exposed to the weather.
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Only minimal. They need to be pressure-washed every 2-3 years, and the sealed joints need to be checked every 3-5 years. If necessary, foam arches can be repainted (acrylic latex paint is suitable).
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It depends on the complexity of the arch shape and the number of parts that need to be installed. In general, our EPS arches are light enough for DIY enthusiast to mount them on their own. However, for large-scale projects, you’ll need the help of professionals. In any case, we include detailed installation instructions with your order and number the components to facilitate the assembly process.
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Original price $175.00 - Original price $175.00Original price$175.00$175.00 - $175.00Current price $175.00Decorative Arch Trim ARCH01
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Original price $175.00 - Original price $175.00Original price$175.00$175.00 - $175.00Current price $175.00Decorative Arch Trim ARCH04
Royal Foam USIncrease the value of your home and transform ordinary to interesting with over 100 designs, we have something to match every décor style. Decorati...
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Original price $175.00 - Original price $175.00Original price$175.00$175.00 - $175.00Current price $175.00Decorative Arch Trim ARCH05
Royal Foam USIncrease the value of your home and transform ordinary to interesting with over 100 designs, we have something to match every décor style. Decorati...
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Arches and Keystones
Decorative arches help create elegant architectural accents for doors, windows, and facades. These curved elements frame openings and add visual depth to exterior design. In addition, keystones emphasize the center of the arch and complete the overall composition.
Traditional stone arches often create serious structural challenges. They are heavy, expensive to install, and require significant support. However, modern decorative arches manufactured from EPS foam solve many of these issues. Because the material is lightweight, builders can install arch systems without complex structural reinforcement.
As a result, architects and contractors frequently choose decorative arches for both residential and commercial projects.
Decorative arches for doors, windows, and facades
Decorative arches appear in many architectural styles. For example, residential homes often use them to highlight entrances and window openings. Commercial buildings also install decorative arches to create visually strong facades.
In addition, EPS foam construction makes installation significantly easier. Contractors can position and secure arch elements quickly because the material remains lightweight.
Therefore, decorative arches provide the classic appearance of masonry structures while simplifying construction work.
EPS foam decorative arches and keystones
EPS foam technology allows manufacturers to produce detailed architectural components with minimal structural load. Decorative arches produced from expanded polystyrene weigh far less than stone or concrete alternatives.
Because of this reduced weight, builders can install decorative arches without reinforcing existing walls. Moreover, protective polyurea coatings strengthen the surface and protect it from environmental exposure.
These coatings improve resistance to:
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moisture
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UV radiation
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temperature changes
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surface wear caused by outdoor conditions
As a result, decorative arches maintain their appearance even in demanding climates.
Precision manufacturing with CNC technology
Modern CNC equipment allows manufacturers to produce accurate curved shapes. Engineers first create digital models using CAD software. Then CNC milling machines cut EPS blocks according to programmed tool paths.
This process ensures precise symmetry and consistent dimensions. For example, paired decorative arches for doorways remain identical during production.
In addition, multi-axis CNC systems allow manufacturers to create complex shapes such as elliptical arches and detailed keystones.
Types of decorative arches
Architectural design often determines which arch form works best. Different shapes help create specific visual effects.
Roman arches
Roman arches feature a semicircular profile. This classic design distributes visual weight evenly and works well in traditional architecture.
They are commonly used in:
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residential entrances
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window surrounds
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exterior facades
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commercial buildings
Segmental arches
Segmental arches use a shallow curve rather than a full semicircle. Therefore, they work well in buildings where ceiling height is limited.
Architects frequently include them in Craftsman and Prairie style designs.
Elliptical arches
Elliptical arches feature elongated curves that emphasize vertical space. Designers often install them in large entryways or high-ceiling interiors.
Because of their geometry, these structures require precise manufacturing methods.
Decorative keystones as architectural accents
Keystones complete the visual structure of an arch. Historically they helped lock stone blocks together. Today decorative keystones serve mainly as design accents.
Manufacturers produce keystones in several styles:
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smooth minimalist designs
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fluted decorative profiles
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scrollwork elements
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cartouche panels for monograms
When combined with decorative arches, keystones create a complete architectural frame.
Advantages of lightweight arch systems
EPS decorative arches offer several practical advantages compared with masonry construction.
First, lightweight materials reduce structural load. Therefore, builders can install arches without major reinforcement.
Second, installation becomes significantly faster. Construction teams can position and secure arch components without heavy equipment.
Third, protective coatings improve durability.
EPS arch systems resist:
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moisture exposure
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UV radiation
-
temperature variation
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outdoor surface wear
As a result, decorative arches remain stable and visually consistent for many years.
Decorative arches in modern construction
Architects continue to use decorative arches because they create strong visual rhythm across facades. At the same time, modern materials simplify installation and reduce construction costs.
EPS foam technology allows builders to achieve classical architectural designs without the engineering challenges of traditional masonry. Therefore, decorative arches remain a practical solution for both residential and commercial architecture.