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KWS MFI® System Cladding Attachment

Extreme Insulation Efficiency + Adjustable + Versatile + Engineered = Simple


  • KWS MFI System: ONLY 7%-20% Loss of R-Value
  • Fiberglass Clips: 14%-27% Loss of R-Value
  • Aluminum Brackets: 18%-41% Loss of R-Value
  • Horizontal Z-Furring: 35%-53% Loss of R-Value

*Lost R-Value percentage will vary based upon exact wall assembly configuration. Values shown assume typical 16″ OC steel studs and 24″ spacing of brackets/rails with varying thickness of insulation.

The KWS MFI® System dramatically reduces the thermal bridging within rainscreen wall assemblies, while providing limitless design options for building facades; combining energy efficiency, façade versatility, and long term sustainability. Being primarily comprised of steel, the MFI System offers a resilient, durable and non-combustible option to meet today’s high demand.

The MFI System uses unique thermally isolated intermittent clips – called Thermabrackets® – that can be spaced all the way up to 32” O.C. They use a unique thermal isolation assembly, called ThermaStop™, creating one of the most thermally efficient mineral fiber cladding attachment systems on the market today – typically outperforming standard metal clips and rails and even FRP brackets and rails.

The continuous rails attaching to the brackets may be oriented vertically or horizontally. Quickly plumb facades during install with an adjustable rail/bracket connection or use KWS unique, self-aligning, structural shims. The MFI System may be used with or without secondary rails for fiber cement, metal panels, terra cotta, phenolic panels or Aluminum Composite Material (ACM) and many more.

View our frequently asked questions for more information.

The MFI System has two versions: S-Series and D-Series

Custom bracket sizes are available up to 16″ long. See our HD ThermaBracket® for greater load capacity.

Both series offer the same versatility and thermal performance listed above.

*Spacing is dictated by design wind pressure, cladding weight, deflection requirements and substrate type. Contact KWS for project specific spacing recommendations.

Advantages to the MFI® System Rainscreen

  • Brackets can be spaced to 48″ O.C.*
  • Rails may be attached to ThermaBracket® in a vertical or horizontal orientation
  • Exterior mineral fiber insulation fits tight around ThermaBrackets without trimming
  • Project specific engineering available
  • Limited 10-year warranty available
  • High corrosive-resistant Zn-Al-Mg ZM40 coating for a long service life vs. typical G90 Galvanized steel
  • ThermaStop™ assembly arrives onsite attached to ThermaBracket – No pre-assembly required
  • Attach nearly any cladding with easy and efficient installation and detailing
  • Wall anchors included
  • Minimal thermal bridging
  • Accommodates up to 6″ of outboard insulation – standard. Custom available.
  • Faster installation: Built-in adjustability easily plumbs old and new walls equating to labor cost-savings
  • Pre-engineered and tested (substrate connection detailed per project)
  • Ideal for renovations
  • Extremely cost competitive compared to typical means of exterior insulation


  • S: Static – the S-Rail to ThermaBracket-S connection is fixed
  • S-Rail Cavity Size: 3/4″ or 1″ (+ secondary rails if needed, see typical details and specifications)
  • Adjustments for Substrate: use Knight’s supplied ThermaStop shim without sacrificing thermal performance – 1/8″ increments
  • ThermaStop shim fits square, straight and flat to the back of the ThermaStop system by means of raised lips that securely lock the shim in-place for maximum structural integrity
  • KWS’ isolator shim is included with every S-Series MFI System shipped


  • D: Dynamic – the D-Rail to ThermaBracket-D connection is adjustable
  • D-Rail Cavity Size: 1.5″ (+ secondary rails if needed, see typical details and specifications)
  • Adjustments for Substrate: rail-to-bracket connection has built in adjustability of 3/4″ for a quick, simple and precise installation
  • ThermaStop shims may also be used if further adjustment is required.


  • SYSTEM DEPTH: See bracket size PDF or custom depths available
  • RAIL FINISH: Mill or Black
  • RAIL GAUGE: 18-GA or 16-GA – both 50 ksi
  • RAIL LENGTH: 120″ Standard or custom lengths available

*Spacing of components varies by project based on project specific conditions. Maximum allowable spacing and dead load (weight of cladding) is based on the total load (dead + live) acting on the assembly and connections. Depending on the system, insulation thickness will influence the systems capacities.

Wall anchors must be specified and supplied by KWS for an extended written limited warranty. KWS will specify the exact anchor type, embedment depth and spacing for anchors in project specific engineering packages. ThermaStop thermal isolation washers must be used on all types of wall anchors with the HCI or CI System, regardless of the substrate.

NOTICE: No freedom from any patent owned by Knight Wall Systems or others is to be inferred. Because use conditions and applicable laws may differ from one location to another and may change with time, Customer is responsible for determining whether products and the information in this document are appropriate for Customer’s use. NO EXPRESS WARRANTIES ARE GIVEN EXCEPT FOR ANY APPLICABLE WRITTEN WARRANTIES SPECIFICALLY PROVIDED BY KNIGHT WALL SYSTEMS. ALL IMPLIED WARRANTIES INCLUDING THOSE OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

CI, CI-Girt, MFI, ThermaZee, ThermaBracket, TermGirt and PanelRail are registered trademarks controlled by Knight Wall Systems, Inc. ThermaStop is a trademark of Knight Wall Systems, Inc. Patents US 11,299,891; 11,286,676; 9,856,655; 9,732,518; 9,677,268; 8,429,866 and others pending. This list is not exhaustive and Knight Wall Systems does not waive its rights in regard to other patents or trademarks that are not listed.