Engineering GuideDoc ref: MM-EX-01

How to Choose Expanded Metal

A practical guide to selecting SWD, LWD, and strand configuration for architectural, industrial, and enclosure applications.

Core dimensional variables

Standard nomenclature reference

ASTM F1267
SWD

Short way of design

Distance from the center of one bond to the center of the next bond along the short diamond axis.

LWD

Long way of design

Distance from the center of one bond to the center of the next bond along the long diamond axis.

Strand

Width & thickness

The width of metal fed per stroke and the gauge thickness of the base sheet before expanding.

Raised (Standard) vs. FlattenedCarbon, SS, Aluminum
Technical engineering reference

Expanded metal specification guide

Find the right mesh dimensions, profile style, and material grade for your load and open area requirements.

Section 01

1. Diamond geometry & mesh dimensions

Expanded metal is measured across the axes of the diamond. Always specify the Short Way of Diamond (SWD) first, followed by the Long Way of Diamond (LWD).

Industry Standard: SWD x LWD
SWD
Short way of design (or diamond)

Distance measured from the center of a bond to the center of the adjacent bond across the short diamond axis.

Specification impact: Dictates the vertical opening size, structural rigidity under point loads, and visual obstruction angles.
LWD
Long way of design (or diamond)

Distance measured from the center of a bond to the center of the adjacent bond along the long diamond axis.

Specification impact: Determines horizontal span capability, overall diamond width, and maximum sheet coverage.
W
Strand width

The amount of metal slit and stretched between each diamond opening.

Specification impact: Directly alters open area percentage, airflow, optical transparency, and overall sheet mass.
T
Strand thickness

The gauge or original thickness of the base metal plate before expanding.

Specification impact: Determines shear capacity, impact deflection limits, and weight-bearing ratings for industrial walkways.

Balancing airflow, visibility, and strength

Select your primary design intent to view typical mesh parameters and open area target ranges.

Maximum ventilation & high airflow65% – 85%
Typical SWD: 0.50" – 1.50"
Strand config: Narrow strand width (0.070" – 0.125") with standard gauge

Minimizes backpressure in HVAC louvers, radiator grilles, and compressor housing screens.

Balanced protection & airflow45% – 60%
Typical SWD: 0.25" – 0.75"
Strand config: Medium strand width (0.090" – 0.150") for stable barrier strength

Recommended for electrical equipment enclosures and conveyor safety guards.

High privacy & directional shade25% – 40%
Typical SWD: 0.187" – 0.50"
Strand config: Wide strand width (0.125" – 0.250") in standard raised profile

Strands angled at 45 degrees block direct overhead sun while permitting horizontal sightlines.

Section 02

2. Strand width & thickness: engineering strength vs. weight

Because expanded metal is manufactured without welds or joint bonds, strand thickness and width determine how load distributes across the continuous diamond pattern.

Strand thickness (T) vs. deflection
Governs cross-sectional yield strength

Strand thickness corresponds to the original sheet gauge. Increasing thickness by 25% delivers up to a 90% increase in perpendicular point-load resistance before visible deflection.

Pedestrian catwalks: Require minimum 0.188" to 0.250" thickness to prevent bounce over 48-inch spans.
Machine guarding: 0.060" to 0.100" gauge provides OSHA-compliant impact shielding without dead weight.
Filtration cores: 0.020" to 0.040" light gauge minimizes pressure drop while holding filter media.
Strand width (W) vs. open area
Controls aperture size and weight per square foot

The feed progression of the expanding knife dictates strand width. A wider strand increases overall sheet weight and creates broader structural bridges across the bond points.

Weight calculation: Lbs per sq. ft. scales proportionally with strand width when base gauge is constant.
Rigidity enhancement: Wide strands stiffen standard expanded profiles against twisting during framing.
Cut-edge stability: Broader strands resist deformation when perimeter edges are sheared to size.
Section 03

3. Standard (raised) vs. flattened profiles

Choosing between standard (as-expanded) and flattened profiles affects surface texture, directional rigidity, framing tolerances, and friction coefficients.

Engineering criteriaStandard (raised) profileFlattened (cold-rolled) profileOptimal application
Surface geometryRaised knuckle angles creating a 3D textured planeCold-rolled completely smooth and level in a single plane
Standard: Grip and structural deflection resistanceFlattened: Safe contact, sliding items, and flush framing
Overall sheet thickness1.5x to 2.5x the original raw sheet gaugeEquivalent to or slightly thinner than base material gauge
Standard: Rigidity and high load-bearing without framingFlattened: Tight tolerances, sliding tracks, and enclosures
Slip resistanceHigh multi-directional traction (ideal for catwalks & ramps)Low friction, tactile-friendly for hand contact
Standard: Industrial walkways, stairs, and vehicle rampsFlattened: Cabinetry, partitions, animal cages, and drying trays
Airflow & light diffusionDirectional deflection depending on sightline angleDirect orthogonal pass-through of light and air
Standard: Sunshades, privacy louvers, and equipment bafflesFlattened: HVAC grilles, ventilation covers, and filtration

Need detailed load tables for standard or flattened sheet profiles? Explore our dedicated product catalogs.

Section 04

4. Material selection & environmental compatibility

Material selection depends on operational environment, exposure to corrosive chemistries, structural weight limits, and post-fabrication finish requirements.

Carbon steel
ASTM A1011 / A36
Corrosion resistance

Requires post-finish (mill, primed, powder coated, or hot-dip galvanized)

Mechanical profile

High tensile and yield performance for structural framing

Typical applications

Heavy-duty security barriers, mezzanine decking, and concrete reinforcement

Stainless steel
Type 304 / 316 / 316L
Corrosion resistance

Exceptional resistance to chemical washdown, saltwater, and acid exposure

Mechanical profile

Superior high-temperature strength and extreme fatigue threshold

Typical applications

Food processing baskets, chemical wash screens, coastal facade panels

Aluminum
Alloy 3003-H14 / 5052-H32
Corrosion resistance

Naturally forms protective oxide; highly compatible with architectural anodizing

Mechanical profile

Roughly 1/3 the weight of steel with excellent formability

Typical applications

Architectural sunscreens, ceiling panels, lightweight machine guards

Galvanized steel
ASTM A653 G90
Corrosion resistance

Pre-galvanized or hot-dip post-expansion for outdoor longevity

Mechanical profile

Economical high-strength structural base with continuous zinc protection

Typical applications

Outdoor security perimeter fencing, highway trash screens, HVAC cages

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