# How to read construction drawings

> A step-by-step method for reading construction drawings: check titles, dimensions, clashes, and buildability, and know what to send to the calculators.

- By: Editorial Team, Somali Construction Review (https://somaliconstructionreview.com/about)
- Published: 2 October 2026
- Updated: 4 October 2026
- Format: Practical guide (general practice)
- Publication: Somali Construction Review (https://somaliconstructionreview.com)
- Subject: Industry
- Tags: construction-drawings, reading-drawings, site-work, drawing-checks
- Web version: https://somaliconstructionreview.com/blog/how-to-read-construction-drawings

## Key points

- Start with the title block and drawing register to confirm the drawing is the current approved version for the stage.
- Check dimensions and levels on the drawing you are building from, then check the same dimensions on related drawings for clashes.
- The bar bending schedule and drawing notes give the bar diameters, grades, laps and bends that the concrete calculator and construction material calculator take as inputs.

A set of construction drawings carries the shape, size and connections of everything to be built. Reading it means checking that what is drawn can be built, that the dimensions agree, and that nothing is missing for the next trade. By the end, a reader can work through a drawing sheet by sheet, spot the questions to put to the designer, and pull out the lengths and bar details the site's calculators need.

## What should you check first on a drawing?

Open the title block and the drawing register. Confirm the project, the drawing number, the revision, the date, the scale, and the stage the drawing serves. Check whether the drawing is marked approved for construction. Without approved drawings, what is to be built is open to interpretation on site, and changes are hard to price.

A drawing register lists every sheet issued for the project. Use it to confirm you hold the latest revision of each sheet. Design-and-build contracts produce drawings as work proceeds, so some sheets may be marked preliminary.

Work through these checks:

1. Read the title block: project name, drawing title, number, revision, date, scale, and who drew and checked it.
2. Find the revision cloud or triangle on the sheet and compare it with the register.
3. Read the general notes. They carry the specification items that apply across the sheet: concrete grade, bar grade, cover, and any workmanship notes.
4. Check the north point and the grid references.
5. Confirm the drawing is approved for the stage you are about to start. If it is not, ask the architect or engineer responsible for it.

## A worked example: four features on a floor plan

The labelled drawing below is sheet A1.2 from an openly licensed educational farmhouse drawing set. It uses US feet and inches. It illustrates reading conventions; it is not an approved drawing for a Somali construction project.

![Labelled first-floor plan A1.2: written dimensions, door swing, section reference and title block.](https://somaliconstructionreview.com/illustrations/reading-floor-plan.webp)

Source: [Jay Osborne / Amatect](https://commons.wikimedia.org/wiki/File:Farmhouse_Drawing_Set_V-001.pdf). Teaching annotations by Somali Construction Review. Original and annotated drawing: [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/). US feet and inches; educational example.

[Open the full-size drawing](https://somaliconstructionreview.com/illustrations/reading-floor-plan.svg).

1. **Written dimensions:** label 1 points to the overall dimension of 32 feet. Read the stated value; do not measure this resized image. For a unit conversion, 32 feet equals 9.7536 metres; converting the unit does not change or approve the design.
2. **Door swing:** label 2 identifies the front entrance door. Its curved line shows the swing direction. Check that the opening and surrounding space work together.
3. **Section reference:** label 3 identifies 1/A3.1. This means view 1 on sheet A3.1. Open that companion sheet to read the section rather than guessing heights from the floor plan.
4. **Title block:** label 4 identifies the sheet number A1.2. Check the drawing title, date and revision too. The historical issue information on this example does not establish approval for your current project.

The [complete source drawing set](https://commons.wikimedia.org/wiki/File:Farmhouse_Drawing_Set_V-001.pdf) includes the companion sections and elevations. The teaching annotations and their source drawing are shared under [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/).

## How do you read plans, sections and elevations together?

A plan is a view from above. A section is a cut through the building. An elevation is a view from the side. Read them as one set: each view answers a question the other cannot. Dimensions on a plan give lengths and widths; sections give heights and depths; elevations give levels and openings.

Start with the plan to place walls, columns, doors and windows. Then read the section to get floor-to-floor heights, foundation depths and roof pitches. Then read the elevations to check window and door heights and the relationship of the building to ground level. Cross-check the grid lines between views so the same column or wall sits in the same place on each sheet.

A simple cross-check table helps:

| Item | Where to find it | What to check |
| --- | --- | --- |
| Wall lengths | Plan | Grid dimensions and room sizes |
| Floor-to-floor height | Section | Level annotations |
| Door and window sizes | Plan and schedule | Opening sizes match the schedule |
| Foundation depth | Section | Level below ground and soil note |
| Column positions | Plan and grid | Same grid on all sheets |

If a dimension appears on two sheets and does not agree, stop and ask. Do not scale off the drawing to settle the difference.

## How do you find dimensions and levels?

Dimensions are written in figures, not measured off the paper. Find the dimension lines first, then the levels. A dimension line runs between two extension lines and carries the figure. Levels are written as reduced levels or as a note such as top of slab.

Work through the sheet in this order:

1. Find the overall dimensions and the grid spacings.
2. Find the room or bay dimensions that sit inside the grid.
3. Find the level annotations: ground level, top of foundation, top of slab, eaves, ridge.
4. Check that the levels add up. A floor-to-floor height is the difference between two levels, not a separate figure.
5. Mark any dimension that is missing or that does not close.

If a dimension is missing, ask the architect or engineer responsible for the drawing. Do not estimate from the scale bar. The scale bar can change when a drawing is printed or copied, so it is not a measuring device on site.

## How do you read reinforcing and the bar schedule?

The grade and the diameters of reinforcing bars come from the drawings. Laps, bends and hooks come from the bar bending schedule. The schedule is a table of bar marks: each mark gives the bar diameter, the shape code, the number of bars, and the bending dimensions.

Read the schedule with the structural drawings open. Each bar mark on the schedule appears on a plan or section. Check these points:

- Bar diameter and grade: from the drawing notes and the schedule.
- Bar mark: the same mark must appear on the drawing and the schedule.
- Shape code: the standard shape the bar is bent to.
- Cutting length: the length to cut before bending.
- Number: how many bars of that mark go in the element.

The construction material calculator takes wall lengths and heights, doors and windows, slab, beam, column and footing sizes, and the bar schedule as inputs. The concrete calculator takes the same member sizes and the bar details. Reading the drawing gives those inputs. It does not replace a licensed architect or engineer, and it never establishes that a drawing is approved, certified, compliant with a code or safe to build.

## What should you check for clashes and buildability?

A clash is where two things want the same space: a beam and a duct, a door and a column, a pipe and a footing. Buildability is whether the drawn detail can be assembled with the access and materials available. Both checks need the drawings side by side.

Lay the architectural, structural and services sheets together. Work through the following:

1. Check openings against structure: does a door or window sit where a column or beam is drawn?
2. Check services against structure: do pipes or ducts pass through beams or footings?
3. Check headroom under beams and services.
4. Check access: can a person and the materials reach the place shown?
5. Check details: are there sections and enlargements for every junction that needs one?
6. Check circulation: do stairs, doors and corridors work as a route?

> **Tip:** Mark each clash on a copy of the drawing and send it to the designer with a question. A marked-up drawing is easier to answer than a verbal description.

## What does a drawing not tell you?

A drawing does not tell you whether it is approved, whether it complies with a code, or whether it is safe to build. It does not carry the site conditions unless a soil or survey drawing is included. It does not price the work. Reading a drawing is a check on information, not a substitute for a licensed architect or engineer.

The education page sets out three learning paths: beginner, intermediate and professional, built from the site's articles, tools and checked outside resources. On the [education page](/education) a reader can work out which path fits: a beginner can start with the parts of a drawing and the questions to ask; an intermediate reader can work through dimensions, schedules and clashes; a professional can use the paths to refresh checking routines and to bring the drawings into the calculators. Questions about a drawing go to the architect or engineer responsible for it.

## What to do next

Gather your current drawing set and the drawing register. Check the title block and revision on each sheet. Mark missing dimensions, clashes and buildability questions on a copy. Then open the [construction material calculator](/construction-material-calculator) and the [concrete calculator](/concrete-calculator) and enter the wall lengths and heights, door and window sizes, slab, beam, column and footing sizes, and the bar schedule from the drawings. The [construction risk analyzer](/construction-risk-analyzer) can help you check whether the drawings needed for the stage are approved before that stage starts.

## Questions

### What is the first thing to look at on a construction drawing?

Start with the title block. It gives the project, drawing title, number, revision, date, scale, and who drew and checked it. Then check the drawing register to confirm you hold the latest revision and that the drawing is approved for the stage you are about to start.

### How do I read a bar bending schedule?

A bar bending schedule is a table of bar marks. Each mark gives the bar diameter, grade, shape code, cutting length, and number of bars. Read it with the structural drawings open so each bar mark can be found on a plan or section. The grade and diameters come from the drawings; laps, bends and hooks come from the schedule.

### Can I scale dimensions off the drawing?

No. Dimensions are written in figures on dimension lines. The scale bar can change when a drawing is printed or copied, so it is not a measuring device on site. If a dimension is missing, ask the architect or engineer responsible for the drawing.

### What are the common checks for clashes and buildability?

Lay architectural, structural and services sheets together. Check openings against structure, services against structure, headroom, access, details at junctions, and circulation. Mark each clash on a copy of the drawing and send it to the designer with a question.

### What does a drawing not tell me?

A drawing does not tell you whether it is approved, certified, compliant with a code or safe to build. It does not carry site conditions unless a soil or survey drawing is included, and it does not price the work. Reading a drawing is a check on information, not a substitute for a licensed architect or engineer.

### How do drawings feed the calculators?

The construction material calculator takes wall lengths and heights, doors and windows, slab, beam, column and footing sizes, and the bar schedule as inputs. The concrete calculator takes the same member sizes and the bar details. Those figures come from the drawings and the bar bending schedule.

## Sources

- [Education page (Somali Construction Review)](https://somaliconstructionreview.com/education)
- [Farmhouse Drawing Set V-001, sheet A1.2 (Jay Osborne / Amatect; CC BY-SA 3.0)](https://commons.wikimedia.org/wiki/File:Farmhouse_Drawing_Set_V-001.pdf)