Guides · Floor Plan Measurement

How to Measure a Two-Story Home Floor Plan

Measuring a two-story home is simpler than it sounds. The tool handles multi-story homes by letting you trace each floor as a separate polygon. Total GLA is the sum of all above-grade polygons. Here is the complete step-by-step process.

The core approach: one polygon per floor

Create two polygons — one for the ground floor and one for the second floor. Each floor is traced independently. The tool shows individual area for each polygon and a running total. Both floors should be traced at the exterior perimeter (outside face of exterior walls) for ANSI Z765-compliant GLA.

Getting the floor plans

For CubiCasa: each floor is typically on a separate PDF page. Export each page separately and upload individually. For Matterport: the floor plan download includes a separate JPG per floor level. For appraiser sketches showing both floors on one image: trace each floor as a separate polygon in the same session.

Step by step

1. Upload the ground floor plan. 2. Set scale from a labeled dimension. 3. Trace the exterior perimeter of the ground floor above-grade living area — exclude garage. 4. Note the area (e.g., 1,050 sq ft). 5. Upload the second floor plan. 6. Recalibrate scale from the new image. 7. Trace the second floor exterior perimeter. 8. Note the area (e.g., 980 sq ft). 9. Total GLA = 1,050 + 980 = 2,030 sq ft.

Handling the staircase void

Most two-story homes have a staircase opening on the upper floor — the floor doesn't exist above the stair run. When tracing the second floor, exclude this void. Trace around it by placing points at the corners of the void and excluding that area from your polygon. The tool handles concave polygon shapes correctly.

Partial second floors

Many two-story homes have a smaller second floor than ground floor — a partial two-story with a cathedral ceiling over one section. Simply trace the actual second floor footprint as shown on the plan. The cathedral-ceiling area is included only in the ground floor polygon, not double-counted on the second floor.

Verification

For a simple full two-story home (same footprint on both levels), the ground and second floor polygon areas should be roughly equal. A significant discrepancy suggests a tracing error. For partial two-story homes, verify that the second floor polygon matches only the two-story portion of the plan.