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Manufacturer and supplier of roof products and accessories for the metal building industry since 1964
Standing Seam Roof Curb
The R&S Standing Seam Roof Curb fits any trapezoidal or vertical standing seam roof panel. Curb size and design meet any skylight or rooftop equipment requirements. Equipment curbs have a level top for proper RTU operation. Seam-to-seam (R&S Seam Clip) side flanges come standard for a complete weather-tight seal. Economical flat flange models are also available. 1″ foil-faced rigid insulation comes standard, with optional high R-Value models as needed. Roof curbs may also include an interior liner, duct supports, a damper shelf or custom finish that matches the roof color. The R&S Metal Building Roof Curb installs under the roof panel on the up-slope and over the roof panel on the down-slope, which results in a superior watershed condition. In addition, a 20-Year Warranty comes standard on all aluminum curbs. All curb kits may be ordered with subframe, mastic, sealants and fasteners for a complete install. We offer aluminum or steel construction. MBCI Weather-tightness Warranty approved.
Roof Curbs For: HVAC | Exhaust Fans | Skylights | Gravity Vents | Pipe Penetrations
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Seam Clip Curb with Custom Color Finish -
Skylight Roof Curb with Bright White Liner -
Two-Curb System for Heavy Rooftop Equipment -
HVAC Unit Mounted on a Floating Two-Curb System -
Vibration Isolation Rails Supplied when Specified
Features
- Custom-fabricated to match any metal roof profile
- Aluminum (preferred) or steel construction
- 1" rigid insulation standard, higher R-Values available
- Full-penetration/continuous welds
- Two-curb system for heavy rooftop equipment
- Mill or custom color finish
- Partitioned top for HVAC as specified
- Backer-channel, sealants and fasteners for install
- CAD drawings supplied with order
- Structural calculations available upon request (fee)
- Aluminum curbs carry a 20-Year Warranty
- Approved MBCI Weathertightness Warranty Curb
- Description
- Model Guide
- Sizes & Weights
- Documents
- FAQ
- R&S Insights
Metal Building Roof Curb Specifications
| Material Options | 0.080 aluminum 18 GA, 14 GA or 16 GA aluminized steel 1″ Rigid Insulation R6.5 (higher R-Values available) |
| Construction | Full penetration welds, thoroughly tested Mitered corners for true square top |
| Curb Upslope | Flange installs under panel Closures welded or shipped loose Integrated 4″ high water cricket Min 9″ between up-slope curb wall and closures |
| Curb Downslope | Flange installs over panel Caps (straps) welded or shipped loose Minimum 3″ down-slope flange |
| Curb Side Flanges | Seam-to-seam, integrates with roof panel Minimum 3″ between curb sidewall and panel seam |
| Curb Top | Level top for mechanical equipment or as specified Skylight curbs slope with roof |
| Dimensions | 6″ – 8″ curb height on up-slope (custom heights available) |
| Finish Options | Aluminum mill finish Galvanized finish Powder coat (standard colors or custom) Kynar (exact match) |
| Accessories | 14 GA backer-channel Sealants, fasteners |
| Certifications | Engineering calcs, stamped submittals (additional costs apply) |
| Warranty | 20 Years (aluminum) MBCI 20 Year Weathertightness Warranty Curb 1 Year (steel) |
Type If Curb (Internally-Flanged)
Typical design for Varco Pruden and Butler roof systems.
Same design / construction with the following exceptions:
| Curb Upslope | Upslope base flange breaks inward 2″ Includes 2-piece water diverter assembly and backer channel |
| Curb Downslope | Downslope base flange breaks inward 2″ Integrated caps in curb wall accept panel highs |
| Curb Side Flanges | Side base flanges break inward 2″ |
| Backer Channel | Backer channel and water diverter assembly Included |
Roof Curb Options
| Curb Liner | Conceals insulation, mill or white finish, complete kit for install |
| Ridge Mount | Installs on ridge condition, double pitched |
| Collar Top | Square-to-round transition |
| Over / Over | Up-slope and down-slope over roof panel |
| Non-Insulated | Cost savings when insulation not required |
| High R-Value |
2″ thick insulation for R14 value (other thicknesses available) |
| Damper Shelf | Damper support for exhaust fan |
| Duct Supports | Blank-offs, duct supports for HVAC equipment |
| Vibration Iso Rails | Vibration isolation rails pre-installed for HVAC equipment as specified |
Curb Model Guide
Provide roof panel make, model, seam spacing and pitch when requesting quote.
| Model | LxWxH | Side Flanges | Closures/ Caps | Upslope / Downslope | Curb Top | Insulation | Material | Finish | Options |
| MBS: Standing Seam | T: Trapezoidal Seam Clip V: Vertical Seam Clip R: Flat Flange F: Internally Flange |
1: Fixed / Welded 2: Loose / Field Located* 3: None 4: Up-slope Flat, Down-slope Offset * Available on Flat Flange curbs only |
U: Under / Over O: Over / Over |
L: Level S: Slope w/ Roof |
Y: Insulated X: Non-Insulated |
A: Aluminum G14: 14 Gauge Galvanized Steel G16: 16 Gauge Galvanized Steel G18: 18 Gauge Galvanized Steel |
M: Mill P: Powder Coat K: Kynar |
CL: Curb Liner RM: Ridge Mount FC: Floating 2-Curb System* CT: Collar Top DS: Duct Supports VR:Vibration Isolation Rails * Inner Curb Dimension |
Example
MBS-48x96x8-T1US-YAM-DS-VR: Roof curb for a Standing Seam Roof, 48″ Wide x 96″ Long x 8″ High, Trapezoidal Seam Clip Side Flanges, Fixed Contour Caps with “Under Panel” up-slope condition and “Over Panel” down-slope condition. Curb top flange is sloped with the roof, curb walls are insulated and fabricated of Aluminum with a Mill finish. Kit delivered with HVAC duct supports and vibration isolation rails.
Terminology
Closure: seals trapezoidal panel at up-slope curb opening (under panel)
Cap: seals trapezoidal panel at down-slope curb opening (over panel)
Trapezoidal Seam Clip (T): side flanges integrate with trapezoidal standing seam roof panel
Vertical Seam Clip (V): side flanges integrate with vertical standing seam roof panel
Layover Side Flanges (R): side flanges extend and layover next natural high rib
Flat Side Flanges (R): flat side flanges 3″ typical
Internally Flanged (F): perimeter base flange breaks / seals inside curb wall
Under / Over (UO): up-slope installs under, down-slope installs over roof panel
Over / Over (OO): up-slope and down-slope flanges install over roof panel
Floating 2-Curb System (FC): Inner weight-bearing curb and outer flashing curb (heavy equipment)
Ridge Mount (RM): Inner weight-bearing curb and outer flashing curb (heavy equipment)
Curb Liner (CL): white or mill finish liner on inside of curb wall; conceals insulationFloating
Collar-Top (CT): square-to-round transition for pipe penetrations
All curbs custom-sized to meet project specifications. Curb weight provided with order.
Documents
Additional curb configurations available, call for details
| Product Description | Model | Submittal | Specifications | Installation | Warranty |
| Trapezoidal Seam Clip | MBS-T | WORD | |||
| Vertical Seam Clip | MBS-V | WORD | |||
| Flat Side Flanges | MBS-R | WORD | |||
| Internally-Flanged | MBS-F | WORD | |||
| Ridge Mount | MBS-R-RM | WORD | |||
| Floating 2-Curb System Trapezoidal Seam Clip |
MBS-T-FC | WORD | |||
| Floating 2-Curb System Vertical Seam Clip |
MBS-V-FC | WORD | |||
| Floating 2-Curb System Flat Side Flanges |
MBS-R-FC | WORD |
Curb Sub-Framing (Backer Channel)
| Accessories | Model | Submittal | Specifications | Installation | Warranty |
| Backer Channel Trapezoidal Seam Clip |
SUB-MBS-T | ||||
| Backer Channel Vertical Seam Clip |
SUB-MBS-V | ||||
| Backer Channel Flat Side Flanges |
SUB-MBS-R | ||||
| Backer Channel Internally Flanged Curbs |
SUB-MBS-F |
Additional Support Documents
Downslope Loose ContourInternal FlangeVertical Standing SteamPDF
| Description | Curb Type | Roof Type | Installation Guide |
| Downslope Loose Contour | Internal Flange | Trapezoidal Standing Seam | |
| Downslope Loose Contour | Internal Flange | Vertical Standing Steam | |
| Curb Wall Section View | Relevant to All Curb Types | Relevant to All Roof Types |
Standing Seam Roof Curb FAQ
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1. What is the primary purpose of a standing seam roof curb?
It’s designed to fit any trapezoidal or vertical standing seam roof panel, connecting rooftop equipment to the roof.
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2. What materials are commonly used for these curbs?
They are predominantly made of aluminum or galvanized steel.
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3. What are the insulation options with roof curbs?
They come standard with 1″ rigid insulation, with options for higher R-Values.
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4. How does the roof curb’s construction ensure water doesn’t seep in?
Our standing seam roof curbs are manufactured with full penetration welds and have features like the integrated 4″ high water cricket help in water diversion.
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5. Is there a warranty on these roof curbs?
Aluminum curbs come with a 20-Year Warranty. Steel Curbs come with a 1-Year Warranty.
R&S Insights Blog
Metal Building Roof Curb – How to Choose the Right Application
There are several choices to make when purchasing a metal building roof curb. Your evaluation should take into consideration the conditions on and around the roof… Learn More
What Are HVAC Roof Curbs and What Are They Made Of?
Commercial buildings often have at least one or a combination of these items on the roof: fans, condensers, skylights, hatches, vents, or AC units… Learn More
What Are Some Uses for Rooftop Curbs?
Roof curbs are used extensively on commercial roofs to ensure the safe installation and proper functioning of various components of the roof system, such as HVAC equipment, and more… Learn More
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R&S manufactures a wide array of products to fit your project needs. We aim to supply all of your metal building roof accessory needs, not just one product. Why go to multiple vendors when R&S can supply it all?
