The Short Answer

Measure every wall, gable, dormer and return as a separate shape. Record windows, doors, corners, roof intersections and utilities on individual elevation sketches.

Convert the measured areas into a panel layout based on the selected Gentek SteelTek Supreme profile. Then add project-specific cutting waste and round the total to available carton quantities.

Do not begin with a guessed waste percentage or rely on the home’s floor area. Neither accurately describes the exterior wall surface.

Create One Drawing for Every Elevation

Draw the front, rear and both side elevations separately. Add extra drawings for additions, garages, enclosed porches, dormers and walls that change plane.

Each drawing should show:

• Overall wall width
• Wall height at each end
• Gable base and height
• Window and door dimensions
• Inside and outside corners
• Roof-to-wall intersections
• Soffit and fascia lines
• Utility penetrations and mounting blocks
• Changes in siding profile or color

Label each elevation consistently so photographs, measurements and order quantities can be traced to the same wall.

How to Measure a Rectangular Wall

Measure the wall’s width and height in feet. Multiply the two figures:

For example, a wall that is 30 feet wide and 9 feet high has a gross area of 270 square feet.

Measure each wall rather than assuming opposite elevations are identical. Additions, grade changes and roof transitions frequently create different dimensions.

How to Measure a Triangular Gable

Measure the horizontal width of the gable at its base and the vertical height from the base to the peak:

A gable with a 24-foot base and a 6-foot height has a gross area of 72 square feet.

The square-foot calculation does not account for angled cutting waste. A profile-specific cut plan is still required.

Measure Complex Gables as Several Shapes

Gambrel roofs, clipped gables and stepped additions may not form one simple triangle. Divide the elevation into rectangles, triangles or trapezoids that can be measured accurately.

Calculate each section separately and add the results. Keep the sections visible on the drawing so measurements can be checked later.

Avoid estimating the area from a photograph alone. Perspective can materially distort width and height.

How to Measure Dormers

Dormers create more siding work than their small area suggests. Measure the dormer face, both side walls and any triangular or shaped area above the window.

Also record:

• Window dimensions
• Outside-corner heights
• Roof-to-wall intersections
• Head flashing and sidewall flashing lengths
• Access limitations caused by the roof

Dormers frequently generate a high ratio of trim and cutting waste relative to their square footage.

How to Treat Windows and Doors

Do not automatically subtract every window and door from the gross wall area. Siding must still be cut around openings, and many resulting pieces cannot be reused.

Small and medium openings may reasonably remain within an early gross-area calculation as a partial allowance for cutting waste. Large garage doors and sliding doors deserve separate evaluation.

For an order-ready takeoff:

1. Draw each opening in its actual location.
2. Map the panel courses or vertical runs around it.
3. Identify which cut pieces can be reused.
4. Calculate the remaining unusable material.

This produces a more defensible quantity than deducting all openings or ignoring every opening.

Confirm the SteelTek Supreme Profile Before Converting Area

Gentek currently lists these SteelTek Supreme dimensions:

Verify current product data before ordering because packaging and specifications can change.

Horizontal Siding Requires Course Planning

For horizontal SteelTek Supreme profiles, use the wall height and published exposure to estimate the number of courses. Then use wall width and panel length to plan pieces and laps within each course.

Do not round only at the end of the entire house calculation. Each wall may require a whole additional course or panel that cannot be borrowed from a different elevation.

Course alignment around windows, doors, porches and attached garages also affects appearance. Establish the starting height before relying on a mathematical course count.

Vertical Board and Batten Requires Run Planning

SteelTek Supreme Board and Batten has a 12-inch exposure and a listed panel length of 10 feet. Measure the actual vertical distance each panel must cover.

A wall height slightly greater than the available panel length cannot be resolved by ordering a simple percentage of extra panels. It requires an approved transition or design change.

Board and Batten layouts should also be tested around:

• Windows and doors
• Gable peaks
• Wall centerlines
• Outside corners
• Porch and entry features

Thoughtful layout can prevent awkward narrow panels beside prominent openings.

Measure Inside and Outside Corners Separately

Count every inside and outside corner and record its finished height. Do not multiply the building perimeter by one corner factor.

Corner heights can change where:

• Grade slopes
• Porches meet the house
• Gables begin
• Additions change roof height
• Foundation walls step

Compare measured lengths with available accessory stock lengths and approved overlap or joint requirements.

Measure Starter Strip in Linear Feet

Starter strip is generally associated with the lower edge of horizontal siding walls. Measure the base of each section receiving the starter system.

Account for interruptions such as:

• Doors
• Garage openings
• Attached decks
• Lower roofs
• Masonry transitions

Confirm the appropriate starter or base detail for vertical Board and Batten separately. Do not assume a horizontal-siding starter strip is interchangeable with every profile.

Measure Window and Door Trim by Perimeter

Record the width and height of each opening. The basic perimeter is:

This provides a starting quantity, not a finished order. Head flashing may need extra projection, corners create cut waste and some sills use a different detail from heads and jambs.

Identify the required accessory at each side instead of assigning one generic channel to the entire opening.

Record Roof-to-Wall Intersections

Measure every sloped and horizontal location where siding meets a roof. These areas can require channels, flashing coordination and careful cuts.

Photographs are especially helpful because a simple linear measurement may not show:

• Existing step flashing
• Kick-out flashing
• Roofing condition
• Wall offsets
• Restricted fastening space

Do not bury questionable flashing beneath new steel siding without evaluating it.

Count Utility and Fixture Locations

Count every component that interrupts the siding field:

• Light fixtures
• Electrical outlets
• Faucets
• Exhaust vents
• HVAC penetrations
• Electrical meter bases
• Service entrances
• Cable and communications boxes
• House numbers and mailboxes

Record the dimensions and required projection of each mounting block. Exterior insulation or furring may move the siding plane outward and require extensions.

Soffit and Fascia Require Separate Takeoffs

Wall siding square footage does not include soffit and fascia.

For soffit, measure the length of the eave and the horizontal depth from the wall to the fascia. Multiply those dimensions to estimate area, then account for panel direction, ventilation and stock lengths.

For fascia, record the eave and rake lengths along with the face depth. Include corners, returns and transitions to gutters.

Confirm whether existing soffit, fascia and rainware will remain, be wrapped or be replaced before completing the material package.

Add Waste Only After Testing the Layout

Waste depends on roof pitch, openings, wall lengths, profile direction and opportunities to reuse cut pieces.

PEPA’s vinyl-siding worksheet publishes a 10% allowance, but that should not be transferred automatically to SteelTek Supreme. A simple rectangular horizontal-siding project and a complex Board and Batten exterior can produce very different waste.

Show the calculated net material, project-specific waste and final carton rounding as separate quantities.

Use Measurement Technology as a Tool, Not an Excuse to Skip Verification

Gentek identifies Hover as a measurement and design resource capable of generating project measurements, takeoffs and material lists from captured property information.

Digital measurements can save time and provide useful elevation models. They still need to be reviewed for:

• Hidden or obstructed wall sections
• Actual profile selection
• Custom trim conditions
• Wall depth and concealed layers
• Product-specific panel layouts
• Field changes after the images were captured

An automatically generated area report is not necessarily a finished SteelTek Supreme order.

Measurement Errors Affect Exterior Design

Accurate measurements do more than prevent shortages. They help establish balanced Board and Batten layouts, intentional lap placement and consistent transitions around openings.

A rushed takeoff may leave narrow panels beside a front door, short pieces on a prominent wall or poorly coordinated trim.

Aesthetic planning should happen during measurement and layout—not after the first panels have been cut.

Accurate Records Can Support Future Repairs

Keep the final elevation drawings, material list, profile, color and remaining-panel inventory with the property records.

These documents can make later storm repairs or additions easier to plan. They can also help a future buyer understand the products and quantities used.

Documentation does not guarantee resale value, but it reduces uncertainty about the exterior.

A Practical Quad Cities Recommendation

Quad Cities homes often combine original construction with later garages, porches, dormers and additions. Measure each section independently rather than relying on tax-record floor area or a rough building perimeter.

For projects in Davenport, Bettendorf, Moline, Rock Island and surrounding communities, verify measurements from the ground using safe techniques and appropriate technology. Do not climb roofs or unstable ladders solely to complete a siding estimate.

Suburban Wholesale & Supply can help contractors review current Gentek SteelTek Supreme profiles, dimensions, packaging and accessory requirements. Final measurement and order accuracy remain the responsibility of the estimator and installer.