Manufacturer and supplier of roof products and accessories for the metal building industry since 1964

Standing Seam Roof Curbs

Trapezoidal Standing Seam Roof Curb

Our standing seam roof curbs are custom-fabricated to fit any standing seam metal roof profile. The curbs install under the roof panel on the up-slope and over the roof panel on the down-slope, creating a shingled watershed condition. Seam-to-seam (seam clip) side flanges come standard for complete weather-tightness. In addition, a 20-Year Warranty is available. MBCI Weathertightness Warranty approved.

Roof Curbs For: HVAC | Exhaust Fans | Skylights | Gravity Vents | Pipe Penetrations

  • Description
  • Model Guide
  • Sizes & Weights
  • Documents

Specifications

Material 0.080 aluminum
18 GA, 14 GA or 16 GA aluminized steel
1″ Rigid Insulation R7.2 (higher R-Values available)
Construction Full penetration welds, thoroughly tested
Mitered corners for true square top
Curb Up-slope Flange installs under panel
Closures welded or shipped loose
Integrated 4″ high water cricket
Min 9″ between up-slope curb wall and closures
Curb Down-slope 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 when specified
Skylight curbs slope with roof
Dimensions 6″ – 8″ curb height on up-slope (custom heights available)
Finish Aluminum mill 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 Up-slope Up-slope base flange breaks inward 2″
Includes 2-piece water diverter assembly and backer channel
Curb Down-slope Down-slope 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

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
Damper Shelf Damper support for exhaust fan
Duct Supports Blank-offs, duct supports for HVAC equipment

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 Flanged 1: Fixed / Welded 2: Loose / Field Located 3: None 4: Up-slope Flat, Down-slope Offset U: Under / Over O: Over / Over L: Level S: Slope w/ Roof Y: Insulated X: Not 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

* Inner Curb Dimension

Example

MBS-48x96x8-T1US-YAM-CL: 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 an interior curb liner.

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 PDF WORD PDF PDF
Vertical Seam Clip MBS-V PDF WORD PDF PDF
Flat Side Flanges MBS-R PDF WORD PDF PDF
Internally-Flanged MBS-F PDF WORD PDF PDF
Ridge Mount MBS-R-RM PDF WORD PDF PDF
Floating 2-Curb System
Trapezoidal Seam Clip
MBS-T-FC PDF WORD PDF PDF
Floating 2-Curb System
Vertical Seam Clip
MBS-V-FC PDF WORD PDF PDF
Floating 2-Curb System
Flat Side Flanges
MBS-R-FC PDF WORD PDF PDF
Accessories Model Submittal Specifications Installation Warranty
Backer Channel
Trapezoidal Seam Clip
SUB-MBS-T PDF PDF
Backer Channel
Vertical Seam Clip
SUB-MBS-V PDF PDF
Backer Channel
Flat Side Flanges
SUB-MBS-R PDF PDF
Backer Channel
Internally Flanged Curbs
SUB-MBS-F PDF PDF

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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?