A set of construction drawings is not one sheet. It is an ordered set of documents, and reading it in the right order is what makes it legible. Opening a sheet at random does not.
That order starts with the architectural drawings, because they are the base map. Structural and MEP drawings are drawn on top of the architectural plan, so reading those first means reading in the dark.
That is the underlying rule of how to read construction drawings. The rest of this article follows from it: what the set contains, the order to read it in, how the three sets differ, and an exercise on a real drawing with answers.
Learning how to read construction drawings this way needs no drafting skill, and the article does not assume you know AutoCAD. The buyer approving a steel order, the site accountant checking quantities before releasing money, the owner wanting to know whether the builders are doing it right — all three can work through a set once they have this.
Who needs to read drawings without being an engineer
In the Institute's drawing-reading classes, fewer than half the students studied construction. The rest are:
- Estimators, accountants and buyers at construction companies. Every figure they handle starts from a drawing: the weight of steel to order, the volume of concrete to certify, the finished area to check against an invoice. If you cannot read the drawing, you have to take somebody else's word for all of it.
- Sales staff, property agents and interior designers. Reading an apartment plan, knowing which wall is structural and cannot be removed, understanding levels and clear dimensions — clients ask about these every day.
- Small developers and people building their own house. Whoever pays the bill needs to check that the work follows the design, at least at the points that cannot be undone once the concrete is poured.
- People moving into the construction industry, especially towards estimating, quantity surveying or project management: drawings are the first door. Where to start learning construction cost estimating? puts them ahead of any software.
What they have in common: they do not need to draw, only to read. And reading is learnable in a few weeks if you go in the right order — the Construction Drawing Reading course at the Institute packs that order into six sessions, taught on a real project's documents.
What a set of construction drawings contains
An ordinary building has three main sets, each produced by a different discipline, bound separately and numbered separately.
| Set | Usual code | Content | Who uses it most |
|---|---|---|---|
| Architectural | KT | Floor plans, elevations, sections, construction details (stairs, bathrooms, doors), door and window schedules, finishes | Owners, interior designers, sales, finishing trades |
| Structural | KC | Foundation plan, structural plan for each floor (columns, beams, slabs), member details and reinforcement layout, bar schedules | Structural trades, estimating, buying, supervision |
| MEP (mechanical, electrical, plumbing) | Đ, N, ME or MEP | Schematic diagrams, equipment layout, cable and pipe routes, installation details | MEP trades, finishing, interiors |
Every sheet carries a title block in the bottom right corner: project name, drawing name, scale, sheet number, drawn by, checked by, date. The first sheet of each set is usually the drawing index and the general notes — where the conventions that apply to the whole set are recorded (concrete grade, steel grade, cover, datum level). Beginners skip those two sheets, and misread many of the sheets that follow as a result.
Symbols and presentation follow the Vietnamese standards (TCVN) for construction drawings, administered by the Ministry of Construction, so sets produced in Vietnam are fairly consistent with each other. Three ideas to grasp before opening any sheet:
- Scale. A drawing at 1:100 means 1 cm on paper equals 100 cm in reality. Always read the figure written on the drawing rather than measuring the paper with a ruler — prints stretch and shrink.
- Gridlines and levels. Gridlines (A, B, C… and 1, 2, 3…) are the grid used to locate everything; levels (±0.000 is usually the finished floor of the ground storey) locate things vertically. Every member is named by its gridline and its level.
- Section and detail marks. An arrow with a letter and number (for example "1/KC-05") says that section or detail 1 is drawn on sheet KC-05. This is how the sheets link to each other; reading drawings is largely a matter of following those arrows.
The order to read construction drawings in
Beginners open the sheet that looks most important and read every detail on it. Experienced people go from the whole to the part, in five steps — and this is the order to adopt from the start.
Step 1 – Read the general notes and the index. Learn how many sheets there are, which conventions apply, which materials are used. Ten minutes here saves hours later.
Step 2 – Read the architectural plan of each floor. Build a picture of the building: how many storeys, what rooms are on each, where the walls are, which way the doors swing, where the stairs rise. Read the ground floor first, then compare each floor above with the one below to see what changes.
Step 3 – Read the elevations and sections. Elevations give the external shape and the storey levels; sections give the inside vertically: clear heights, slab thickness, floor levels. Combined with the plans, you have now built the house in your head.
Step 4 – Read the structure in construction sequence. Foundations first, then columns, beams and slabs floor by floor. On each structural plan, find which member is where (by gridline) and what size it is, then follow the reference to the detail sheet for its reinforcement. Compare the structural plan with the architectural plan of the same floor: structural columns have to sit inside architectural walls, and beams must not cut across a doorway.
Step 5 – Read MEP over the architectural plan. Schematics first, to understand the system; then the layout, to see where equipment sits, which route the pipes and cables take, and where they pass through beams and slabs — the crossings are where clashes with the structure happen.
That order holds for every building, from a townhouse to an apartment block. Only the number of sheets changes.
Architectural, structural, MEP: what changes when you read them
They are all drawings, but each is read with a different question in mind.
Architectural drawings: "what does it look like and how is it used?" Watch the walls (heavy lines; two parallel lines hatched or filled mean masonry or concrete), the doors (the arc shows which way they open) and the stairs (the arrow shows the up direction). Then the finishes notation and the door schedule. Architectural dimensions are usually finished dimensions; a clear dimension is the gap between two finished faces.
Structural drawings: "what holds it up?" Watch the member marks (C1, D2, S3 — column, beam, slab plus a number) and the section sizes (220×400 means 220 mm wide, 400 mm deep). Then the reinforcement: number of bars, diameter and spacing. Structural dimensions are bare concrete, before plaster, so they are always slightly smaller than the architectural dimensions at the same place.
The structural set carries enough conventions of its own to need a separate article. Reading it from the general notes through to the bar schedule, and what notations such as 4Ø16 and Ø8a150 mean, is covered in how to read reinforced concrete structural drawings.
Estimators live in this set. What is quantity take-off? is about extracting figures from it, and the Construction Cost Estimating course is the next step.
MEP drawings: "where does it run and what does it connect to?" Watch the schematics (read as diagrams, not to scale), the equipment symbols (sockets, switches, lights, taps, floor drains) and the routes of pipes and cables on the layout. The most useful thing for a non-specialist: knowing where pipes and cables are buried in walls and slabs, so nobody drills into them and no one chases out a wall at random.
One habit our lecturers insist on: whatever sheet you are reading, keep the architectural plan of the same floor beside it. Architecture is the base map; structure and MEP are drawn on top of it.
An exercise on a real drawing
The information below comes from the second-floor structural plan of an actual townhouse, simplified. Answer the five questions before looking at the answers.
Data: Gridlines 1–2–3 at 4.0 m centres; gridlines A–B at 5.0 m centres. Column C1, 220×220, at every grid intersection. Beam D1, 220×350, on gridlines A and B; beam D2, 220×300, on gridlines 1, 2 and 3. Slab S1, 100 thick. Note: "Second floor level: +3.600. Concrete B20. Bars Ø10 and above: CB300-V." On the detail sheet, beam D1 has 3Ø16 bottom, 2Ø16 top, and stirrups Ø6a150 in the middle and Ø6a100 at the ends.
- How many columns are there on this floor?
- Which beam is deeper, D1 or D2, and by how much?
- What is the level of the underside of beam D1, if the top of the beam is flush with the slab?
- What does "Ø6a100 at the ends" mean, and why are the stirrups closer together there than in the middle?
- Which grade of steel are the Ø16 bars in beam D1?
Answers: (1) Three gridlines × two gridlines = 6 columns. (2) D1 is 350 deep, D2 is 300, a difference of 50 mm. (3) +3.600 − 0.350 = +3.250. (4) Ø6 stirrups at 100 mm centres near the supports; the ends of the beam carry more shear, so the stirrups are closer together. (5) Ø16 is above Ø10, so CB300-V per the general notes — the question most people get wrong, because they did not read the notes.
Four or five right means you have the basics of reading construction drawings. If you missed question 3 or 5, you are reading sheets one at a time instead of reading the set as a whole — which is exactly what the course is built to correct.
The Institute's Construction Drawing Reading course – 6 sessions is designed for people from outside the industry. The six sessions cover: getting used to drawings; symbols and structural drawings; columns, beams, slabs and MEP schematics; architecture in the structural phase; architectural finishes; and a review with a test on a real set. Those continuing into estimating take Construction Cost Estimating; those who want to draft take AutoCAD.
Frequently asked questions
How long does it take to learn to read drawings?
Someone from outside the industry needs about six guided sessions plus two or three weeks reading a real set on their own to handle the drawings of an ordinary building. Large, infrastructure and industrial projects take longer, because of the specialised symbols.
Do I need AutoCAD to read drawings?
No. Reading and drafting are different skills. Being able to open a CAD file to zoom and measure is convenient, and takes about one session to learn, but reading a print or a PDF is enough for most jobs.
Which set should a beginner start with?
Architecture, because it is the easiest to picture and it is the base for the other two. Then structure, if your work involves quantities, money and the structural phase; MEP if it involves finishes and interiors.
What is the difference between design drawings and as-built drawings?
Design drawings are what will be built; as-built drawings are what was built, produced by the contractor afterwards and recording every change from the design. Payment, final accounts and later repairs all work from the as-built set.
Can I teach myself from material on the internet?
For symbols and concepts, yes. The hard part — reading a whole set and spotting where the disciplines disagree — needs a real set of documents and somebody to point out how you misread it, because you cannot tell on your own where your understanding went wrong.