How to Measure an Existing Aluminum Siding Profile

Matching old aluminum siding starts with good measurements.

A contractor can look at a piece of siding and think, "That's probably Double 4," but "probably" is not good enough when you're ordering material for a repair.

Two siding panels can look very similar from the front and still have different exposure, butt depth, locking geometry or overall dimensions.

At Suburban Wholesale & Supply, we encourage contractors to measure the complete profile before comparing an older siding panel with current Gentek aluminum products or other replacement options.

Start With a Full Piece Whenever Possible

The best sample is a complete panel section that includes the nailing hem, face, butt and locking edge.

A broken piece from the middle of the panel may tell you the color and texture, but it may not tell you whether a current panel can actually connect to the existing siding.

Tool #1: Tape Measure

A basic tape measure will handle most of the initial measurements.

Use it for:

• Visible exposure
• Total panel height
• Distance between profile breaks
• Overall width of the sample

Tool #2: Calipers

Calipers can make the inspection more precise.

They are useful for measuring:

• Butt depth
• Lock dimensions
• Small bends and lips
• Panel thickness where practical

You do not always need calipers for a basic profile match, but they can be valuable when two products are very close.

Step 1: Measure the Visible Exposure

Exposure is the amount of each siding course that remains visible after installation.

This is usually the first measurement contractors should take.

Common examples include:

• 4-inch exposure
• 5-inch exposure
• 8-inch exposure

If the panel has two exposures, measure one exposure and then confirm the second.

Understand Double Profiles

A Double 4-inch profile does not mean the entire panel is only 4 inches tall.

It means the panel creates two 4-inch siding courses.

Likewise, a Double 5-inch profile creates two 5-inch siding courses.

Step 2: Measure the Total Panel Height

Measure from the top of the nailing hem to the bottom of the locking edge.

This gives you the total manufactured height of the panel.

This measurement can help distinguish between panels that have similar visible exposures but different locking or nailing systems.

Step 3: Measure the Butt Depth

The butt is the lower projecting edge of the siding course.

Measure how far that edge projects from the plane of the panel.

Butt depth affects both appearance and compatibility.

A deeper butt generally creates a stronger shadow line.

Step 4: Measure the Profile Breaks

On double profiles, measure where the first course transitions into the second.

This helps confirm whether the panel is truly symmetrical and whether both exposures are the same.

It also gives you more data to compare against a current product specification.

Step 5: Inspect the Locking Edge

This is one of the most important parts of the entire identification process.

The locking edge determines how one panel connects to the panel below it.

Inspect:

• Shape of the lock
• Depth of the lock
• Width of the locking lip
• Angle of the bend
• Any hook or return edge

Two panels can match visually and still fail to connect because the locks are different.

Step 6: Inspect the Nailing Hem

The nailing hem can provide additional clues.

Compare:

• Height of the hem
• Slot size
• Slot spacing
• Shape of the upper edge
• Distance from the hem to the first profile break

These details can help confirm whether a replacement panel is truly compatible.

Step 7: Identify the Texture

Measure the profile—but also document the surface.

Is it:

• Smooth
• Woodgrain
• Embossed
• Lightly textured

Texture can be just as important as profile when trying to create a visually acceptable repair.

Step 8: Look for Manufacturer Markings

Turn the panel over and inspect the back.

Look for:

• Manufacturer name
• Product code
• Color code
• Production information
• Ink stamps
• Embossed markings

Even a partial code can sometimes make identification easier.

Step 9: Photograph the Profile From the Side

Take a clear side-profile photograph.

A side view can document the panel shape better than a front photograph alone.

Take:

• Front view
• Back view
• Side profile
• Close-up of the lock
• Close-up of the nailing hem

Step 10: Record the Measurements

Do not rely on memory.

Write down:

• Exposure
• Total panel height
• Butt depth
• Distance between profile breaks
• Lock dimensions
• Nailing hem dimensions
• Texture
• Any manufacturer markings

A complete set of measurements is much easier to compare than a vague description over the phone.

Build a Simple Profile Measurement Sheet

Compare the Profile With Current Gentek Products

Once the measurements are complete, compare them with current Gentek aluminum siding profiles.

Current product families may include:

• Deluxe Aluminum
• Woodgrain Series 2000
• Cedarwood Aluminum

The comparison should include both dimensions and lock compatibility.

Do a Physical Lock Test When Possible

Measurements can get you close.

A physical test is better.

If you have a current sample available, try connecting the old panel to the new sample.

Do not force the connection.

Don't Forget the Color

Profile identification is only half the repair problem.

Once you identify a compatible profile, compare current color options.

Remember that older siding may have weathered, faded or chalked, so a new panel may not visually match even if the original color name still exists.

Compare a Hidden Area for Original Color

If possible, inspect a less-weathered section of the old panel.

Areas hidden behind an overlap or trim piece may give you a better indication of the original color than the exposed face.

Don't Measure Only One Piece if the House Is Available

If you're at the jobsite, verify the profile in more than one location.

Older homes may have repairs or additions that use different siding on different elevations.

Measure the actual wall being repaired.

Watch for Mixed Siding Profiles

Do not assume the entire house uses one siding profile.

Mixed conditions can occur because of:

• Additions
• Previous repairs
• Garage additions
• Storm damage
• Partial remodeling

Document each different profile separately.

A Simple Field Measurement Process

1. Photograph the siding on the house.
2. Remove or obtain a complete sample when practical.
3. Measure the visible exposure.
4. Measure total panel height.
5. Measure the butt depth.
6. Measure profile breaks.
7. Inspect the locking edge.
8. Inspect the nailing hem.
9. Identify smooth or woodgrain texture.
10. Look for manufacturer markings.
11. Take close-up profile photographs.
12. Record all measurements.
13. Compare with current product specifications.
14. Physically test compatibility when possible.
15. Then compare color.

A Better Counter Explanation

Avoid the "Looks Close Enough" Mistake

This is where contractors can get into trouble.

A panel may look nearly identical while sitting on the counter.

That does not mean it will connect properly on the wall.

Get Help Identifying Aluminum Siding at Suburban Wholesale & Supply

Suburban Wholesale & Supply works with professional siding contractors throughout Davenport, Bettendorf, Moline, Rock Island and the surrounding Quad Cities, Eastern Iowa and Western Illinois.

If you're trying to identify an older aluminum siding profile, bring the most complete sample available along with project photos and measurements.

Our team can help compare the sample with current Gentek aluminum siding products and determine whether a practical profile match may be available.

Sources & Additional Resources

• Gentek Building Products — Deluxe Aluminum Siding: Current profile, exposure, texture and product information for comparison with existing aluminum siding.
• Gentek Building Products — Woodgrain Series 2000 Aluminum Siding: Current Double 4-inch profile, texture and product information.
• Gentek Building Products — Cedarwood Aluminum Siding: Current Double 5-inch aluminum siding profile and product information.
• Gentek Building Products — Product Directory: Current siding profile, specification and color information for Gentek aluminum products.
• The Aluminum Association — Building & Construction: Industry information regarding aluminum exterior building products and material characteristics.
• Vinyl Siding Institute: General siding installation and profile terminology resources useful for understanding exposure, courses and exterior cladding layout.