How-To Guide

How to Check Dimensions on Construction Drawings

Make sure the numbers add up before they become field errors

Dimension errors are some of the most common and expensive mistakes in construction drawings. One wrong number can ripple through the entire project. This guide covers the systematic checks that catch dimension problems before they cause trouble in the field. For a broader approach, see our guide on how to review construction drawings.

Step 1: Check That Dimension Strings Add Up

This is the most basic check: do the parts equal the whole?

1
Add up the individual dimensions in each string. They should equal the overall dimension.
2
Check both horizontal and vertical dimension strings
3
Verify dimension strings on all four sides of floor plans
4
Compare overall dimensions between plans and elevations
5
Make sure building dimensions match site plan setbacks
Watch Out For This
Designer changes one dimension but forgets to update the overall. Now the parts don't add up to the whole. But which number is actually correct?

Step 2: Cross-Check Between Different Views

The same dimension should match everywhere it shows up:

Floor Plan vs. Section
Room widths, corridor widths, wall thicknesses
Plan vs. Reflected Ceiling
Room dimensions, column locations
Plan vs. Enlarged Plan
All dimensions should match at different scales
Section vs. Elevation
Floor-to-floor heights, window sill heights

Step 3: Verify Critical Clearances

Some dimensions have to meet minimum requirements. Review ADA accessibility requirements and egress basics for code-mandated minimums:

Door widths
32" clear for accessibility, 44" for egress corridors
Corridor widths
44" minimum for egress, often 60" for healthcare
Ceiling heights
7'-6" minimum for habitable rooms (varies by code)
Stair dimensions
Tread depth and riser height per code
Equipment clearances
Per manufacturer requirements and code

Step 4: Compare Against Schedules

Schedules have dimensions in them that need to match the drawings:

Door schedule widths should match door openings on plan
Window schedule sizes should match elevations and plans
Room finish schedule heights should match sections
Equipment schedule dimensions should fit in the rooms shown
Structural member sizes should match what's drawn

Step 5: Verify Grid Line Spacing

The structural grid is the backbone of dimensional control:

Grid spacing should be consistent across all disciplines
Grid dimensions should match between structural and architectural
Column centerlines should align with grid intersections
Dimensions to grid lines should be consistent
Grid labels should match between plans and sections

Step 6: When in Doubt, Check the Scale

If dimensions seem off, verify the scale:

Is the stated scale correct for the printed sheet size?
Do scaled measurements match the noted dimensions?
Are details at consistent scales within the same sheet?
Was the PDF printed at the correct scale?
Important
Never scale drawings in the field. If a dimension is missing, submit an RFI. Scaled dimensions aren't contractual and may be wrong because of printing issues. For help with scales, see our drawing scale guide.

Related Resources

How to Review Construction Drawings
Systematic approach to catching all types of errors.
Construction Drawing QA/QC Checklist
Complete checklist for document review.
Drawing Scale Guide
Understand and verify scales on construction drawings.
Construction Rework Costs
The real cost of errors caught too late.
Dimensional Verification
Automate dimension checking with AI analysis.
AI vs Manual Drawing Review
Compare automated and manual review approaches.

Automate Dimension Verification

Checking every dimension string by hand is slow and it's easy to miss things. Articulate's AI can automatically verify that dimension strings add up and flag discrepancies across your drawings.

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