The Short Answer

Furring strips can be useful behind steel siding, particularly when a project includes continuous exterior insulation or needs a defined drainage and drying space. However, furring is not a universal cure for an uneven or deteriorated wall.

The strips become part of the cladding’s attachment system. Their material, thickness, orientation, spacing and connection to the building structure therefore need to be compatible with the siding profile and anticipated loads.

If the installer cannot explain what the furring is accomplishing and how loads travel from the steel panels back to the structure, the assembly is not ready for installation.

What Furring Strips Can Accomplish

A properly designed furring system may serve more than one purpose. The project documents should identify which of the following functions it is expected to perform:

• Provide an approved fastening surface for the siding
• Transfer cladding loads through exterior insulation to the structure
• Create a drainage and drying space behind the cladding
• Establish a flat, consistent exterior plane
• Support trim, corners and other siding accessories

A strip intended only to create a drainage gap may not be sufficient as a structural attachment member. Conversely, a structurally adequate attachment system can still perform poorly if it blocks drainage or leaves unsupported panel edges.

Furring Over Exterior Insulation

Exterior insulation presents an obvious attachment challenge: most foam-plastic insulation is not a structural fastening base. Furring can create a surface for the siding, while longer fasteners connect the strips through the insulation to framing or another approved structural substrate.

Building Science Corporation has researched furring strips attached through thick exterior insulation. Its research found that these assemblies depend on several interacting forces, including fastener behavior, bearing in the wood members, insulation compression and friction between layers.

That is more complicated than merely selecting a screw long enough to reach the stud. Relevant variables include:

• Insulation type and thickness
• Insulation compressive strength
• Furring dimensions and species
• Fastener diameter, length and spacing
• Required penetration into the structure
• Weight of the completed cladding system
• Design wind pressure and building exposure
• Allowable short- and long-term movement

Research on one combination of insulation, furring, fasteners and cladding should not be treated as blanket approval for a different assembly.

Furring Can Create a Useful Drainage Space

A space behind the siding can help incidental water drain and allow materials to dry. Building Science Corporation’s exterior-insulation research describes improved drainage and drying as an important potential benefit of furring-based assemblies.

The cavity is not useful if water cannot enter and leave it predictably. A successful drainage space requires deliberate detailing at:

• The bottom of the wall
• Window and door heads
• Roof-to-wall intersections
• Horizontal material transitions
• Soffits and upper-wall terminations

Openings may also require screening or another approved method of limiting insect entry without preventing drainage and airflow.

A Rainscreen Is Not a Substitute for Flashing

The drainage space behind steel siding does not replace the water-resistive barrier or properly integrated flashing. The wall still needs a continuous drainage plane behind the furring.

Windows, doors, utility penetrations and roof intersections should be flashed to that plane so water can move outward. Face caulk at the siding surface is a maintenance joint, not a complete concealed drainage system.

If the project team cannot point to the drainage plane and trace how water exits at the bottom of each wall section, the water-management design needs more work.

Furring Does Not Automatically Straighten a Wall

Gentek states that SteelTek Supreme’s rigid panels help conceal imperfections in the exterior substructure. That should not be interpreted as permission to install over a badly distorted wall.

Furring follows the surface beneath it unless installers measure, shim or otherwise correct the plane. Strips installed over bowed sheathing can reproduce the same distortion farther outward.

Before siding begins, the installer should check the wall with long straightedges, levels or appropriate layout tools. Pay particular attention to:

• Stud or sheathing irregularities
• Misaligned additions and enclosed porches
• Transitions between masonry and framed walls
• Areas affected by previous water damage
• Walls with several layers of earlier cladding

Furring can help establish a consistent plane, but only when correction is intentional and the shimming method preserves secure attachment.

Common Furring-Strip Failures

Many problems attributed to the siding actually originate in the support system behind it. Warning signs include:

• Fasteners that miss framing: The strip may feel secure initially but lack the intended structural connection.
• Overdriven fasteners: Excessive tightening can crush insulation and pull the furring out of plane.
• Inconsistent strip thickness: Variations can create visible waves or steps in rigid panels.
• Unsupported panel joints: Improper spacing may leave seams or accessories without adequate backing.
• Blocked drainage: Horizontal obstructions can trap water unless the assembly includes a planned drainage path.
• Wet or deteriorated lumber: Furring that shrinks, twists or decays can change the siding plane.
• Improvised orientation: The layout may conflict with the siding profile or leave insufficient support.

Horizontal Versus Vertical Furring

Furring orientation should respond to panel direction, fastening requirements and drainage—not installer convenience alone.

Vertically oriented strips naturally create downward drainage channels. Horizontal strips can interrupt that path unless the system incorporates gaps, cross-furring or another approved drainage method.

A vertical Board and Batten profile may require a different support strategy from horizontal clapboard siding. In some designed assemblies, two layers of furring are used to address both attachment direction and drainage. That increases wall thickness, fastener demands, labor and trim complexity.

The correct configuration must be confirmed for the specific SteelTek profile and wall assembly. Direction alone does not establish structural adequacy.

The Aesthetic Stakes Are Higher With Rigid Steel Panels

SteelTek Supreme is designed to create straight wall lines and pronounced shadow details. Gentek lists a 1/2-inch butt projection for its horizontal profiles and a 5/8-inch batten height for its 12-inch Board and Batten profile.

These strong lines make the installation visually disciplined, but they can also reveal inconsistent preparation. A slight change in the furring plane may become noticeable where sunlight moves across a long wall.

The installer should evaluate the wall from several angles and under different lighting conditions before proceeding. Long, uninterrupted elevations and darker colors deserve especially careful preparation because shadows and reflections can make alignment differences easier to see.

No cladding should be expected to make a structurally uneven wall look perfectly flat.

Added Wall Thickness Changes Every Trim Detail

Furring moves the siding plane outward. When it is combined with exterior insulation, that movement can be substantial enough to change the appearance and function of openings and transitions.

• Windows and doors may require deeper jambs or built-out trim.
• Head flashing must extend beyond the new siding plane.
• Corners need sufficient depth for the selected profile.
• Soffit and fascia intersections may need redesigned closures.
• Light fixtures, outlets and vents may need extension blocks.
• Transitions to brick, stone and foundation walls need finished edges.

From an aesthetic perspective, the thicker assembly can create handsome window recesses and deeper shadows. It can also make original trim appear narrow or poorly proportioned. These consequences should be drawn or mocked up before materials are ordered.

Wind Resistance Depends on the Complete Load Path

Gentek describes SteelTek Supreme as independently tested to withstand intense winds. Product-level testing does not automatically validate every field-created furring assembly.

Wind loads must travel from the steel panel through its fasteners, into the furring, through the furring fasteners and finally into the building structure. A weakness anywhere in that chain can control the performance of the completed wall.

Building height, corner zones, local exposure and substrate condition can affect fastening requirements. Higher-risk or unconventional assemblies may require evaluation by a qualified design professional.

Warranty and Documentation

Gentek’s SteelTek Supreme warranty excludes certain damage associated with improper installation and defects in the wall or materials to which the siding is applied.

Keep the applicable Gentek instructions, fastening specifications, product data, permits and photographs of the furring before it is covered. The photographs should show strip spacing, fastener locations, flashing and the condition of the underlying wall.

Documentation cannot correct a weak installation, but it can demonstrate that concealed work was planned and completed as specified.

Does Furring Improve Resale Value?

Buyers generally do not pay more simply because furring strips are present. They may value what a well-designed assembly delivers: straighter walls, better drainage, documented exterior insulation and carefully finished openings.

There is no credible basis for guaranteeing a particular return on investment from furring or a rainscreen. Resale results depend on the local housing market, the condition of the property and the quality of the visible finished work.

The strongest resale story is not “we added furring.” It is “the steel siding was installed as part of a documented wall system that manages attachment, drainage and exterior appearance.”

A Practical Quad Cities Recommendation

Homes throughout Davenport, Bettendorf, Moline, Rock Island and nearby communities vary widely in age and construction. Some have original wood sheathing, while others have masonry walls, additions or multiple generations of exterior cladding.

Inspect the existing wall before selecting a furring system. Verify the structural substrate, locate damaged areas and coordinate the added thickness with windows, soffits, utilities and adjacent materials.

Suburban Wholesale & Supply can help contractors and property owners compare SteelTek Supreme profiles, colors and related exterior components. The contractor or design professional remains responsible for confirming that the complete attachment and water-management system is appropriate for the building.