Architectural Drawings: 12 Types, Scales and How to Read Them

Architectural drawings are the scaled, measured drawings that describe a building well enough for someone else to approve it, price it and build it. They show where the building sits on its site, the layout of every floor, what each facade looks like, how the building is put together inside, and what each door, window and finish is. They come as a numbered set of sheets, and the same set does three jobs: it gets the building permit, it lets contractors bid, and it is what the crew builds from.

This guide goes through the 12 types you will find in a real drawing set, each with an example from a published project. It also covers the scales US architects use, what sheet numbers like A-101 mean, which drawings each project phase produces and how to read a set you have never seen before. We drew four of the examples ourselves, straight from a BIM model our AI generated. That is also the quickest way to see why one model can produce all of them.

What are architectural drawings?

An architectural drawing is a technical drawing of a building, made to scale and to conventions every architect, engineer, plan reviewer and builder understands. The conventions matter more than the drawing skill. A wall cut by a plan is drawn with a heavy line, a door shows its swing as an arc, and a dashed line means something above you or hidden behind something else. A circle with a number over a sheet code points you to another drawing in the set. Anyone trained to read those conventions can find their way around a set from a different office, in a different city, made in different software.

Architectural drawings (definition): the set of scaled orthographic drawings, plus schedules and notes, by which an architect defines a building's location, layout, appearance, construction and materials for approval, pricing and construction.

Most architectural drawings are orthographic. They look at the building square-on, with no perspective, so a 10-foot wall measures the same at either end. That is what makes them buildable: you can take a dimension off the drawing and trust it. Perspective views and renders show what the building will feel like, but nobody builds from them.

The 12 types of architectural drawings

These are the drawings you will find in a typical architectural (A-series) set, with the scales US offices most often use. Metric projects use the nearest ratio: 1:100 or 1:50 for plans, 1:20 down to 1:5 for details.

The sheet numbers in the last column follow the US National CAD Standard, explained below. Many offices number differently, but most sets you will see in the US look like this.

1. Site plan

The site plan places the building on its lot. It shows the property lines and the setbacks the zoning code requires, the footprint of the building, driveways, walks, parking, landscaping, utility connections and easements, and always a north arrow. Plan reviewers usually start with it, because a building that breaks a setback fails no matter how good the floor plans are. On larger projects the civil engineer draws the grading and utilities on C-sheets, and the architectural site plan only shows the building and what is around it.

Part of a villa site plan at 1:50: the footprint, the planted courtyard, the paved edge and both streets, with dimensions tied to the grid lines. Reference: Architectural Technical drawing Package Villa by Mohamed Nasser on Behance.

2. Floor plan

A floor plan is a horizontal cut through one storey, conventionally about 4 feet (1.2 m) above the floor, looking down. The height is chosen so the cut passes through doors and windows. Everything the cut slices through, mostly walls, is drawn heavy. Everything below the cut, such as the floor, counters and stair treads, is drawn thinner. Things above the cut, like upper cabinets or a beam, are dashed. A construction floor plan adds grid lines, dimension strings, room names and numbers, door and window tags that point to the schedules, and section and elevation markers that point to other sheets.

A ground floor plan at 1:100 with its grid (A to J, 1 to 7) and, beside it, the room schedule and the door schedule for the same floor. Reference: LB Villa, Architectural working drawing by Mohamed Fayed on Behance.

3. Reflected ceiling plan

A reflected ceiling plan (RCP) shows the ceiling as if the floor were a mirror, so it lines up exactly with the floor plan beneath it rather than being flipped. It carries ceiling heights, materials, light fixtures, sprinkler heads, air grilles and access panels. It is where the architect, the electrical engineer and the mechanical engineer have to agree, so a messy RCP usually means coordination problems.

A reflected ceiling plan: two ceiling finishes (tagged CI01 and CI02 and keyed to a legend), two ceiling heights and the light positions, all dimensioned from the walls. Reference: Riyadh Hotel Reception, Interior Shop Drawings by Astro Architects on Behance.

4. Roof plan

The roof plan is the building seen from directly above. It shows slopes with arrows and pitch, ridges, valleys and hips, gutters and drains, parapets, skylights and rooftop equipment. On a flat roof it is mostly about drainage: where the water goes and how the insulation is tapered to get it there.

5. Exterior elevations

An elevation is a straight-on view of one face of the building, with no perspective, named either by direction (North elevation) or by a number keyed on the plan. It shows the overall height, the floor levels as datum lines, every door and window, and the material of each surface, usually with notes calling them out. Elevations are also what most design review boards and homeowners' associations look at, because they are the closest a technical drawing gets to "what will it look like".

The main elevation of the same villa: grid bubbles along the top tie it back to the plan, and the level markers at each side give the floor and roof heights. Reference: LB Villa, Architectural working drawing by Mohamed Fayed on Behance.

6. Interior elevations

Interior elevations do for one wall of a room what exterior elevations do for a facade: cabinets, shelving, tile layouts, mirrors, fixtures and the mounting height of everything. Kitchens and bathrooms always get them, because that is where a few inches matter most.

7. Building sections

A building section is a vertical cut through the whole building, like slicing a cake, marked on the plans with a section line and a pair of arrows showing which way you are looking. It shows what no plan or elevation can: floor-to-floor heights, ceiling heights, the thickness of each floor, how the stairs climb, where the structure is, and how the roof meets the walls. As in a plan, what the cut slices through is drawn heavy and what you see beyond it is drawn light.

A section cut through a villa: basement, two floors, the rooftop rooms and the roof in one view, with every level marked. You can see the curved stair and the double-height windows, which neither the plan nor the elevation shows clearly. Reference: LB Villa, Architectural working drawing by Mohamed Fayed on Behance.

8. Wall sections

A wall section is a tall, narrow section through one exterior wall, from footing to roof, at a large scale. Every layer is drawn and labelled: foundation, slab, framing or masonry, sheathing, insulation, air and water barriers, cladding, and the window head and sill. It is where much of the building's energy and moisture performance is decided, which is why envelope consultants read it closely.

9. Details

Details are the junctions drawn large enough to build: a stair nosing, a window head, a roof edge, a threshold, a handrail fixing. A set can have dozens of them. Each is numbered and called out from the plan, section or elevation it belongs to, so the builder can go from "how does this corner work?" to the exact drawing that answers it.

A stair detail: the hatched concrete, the finish layers, the nosing and the baluster spacing, each dimensioned so it can be built without guessing. Reference: Residential Villa Technical Set, KAITECH Project by Ahmed Selem on Behance.

10. Enlarged plans

Enlarged plans redraw the busy parts of a floor plan at a bigger scale: kitchens, bathrooms, stair cores, elevator lobbies. They carry the fixture positions, clearances and dimensions that would be unreadable at 1/8" = 1'-0", and they are where accessibility clearances get checked.

11. Schedules

Schedules are tables. The door schedule lists every door with its tag, size, type, material, fire rating and hardware. The window schedule does the same for windows. The room finish schedule gives the floor, base, wall and ceiling finish of every room. The tags on the plans (a door tag such as D07, say) point into these tables, which is why a change to a door means editing one row, not twenty drawings. In BIM software, schedules are read straight from the model, so they cannot drift out of step with the plans.

12. 3D views

Axonometrics, isometrics, exploded views and perspectives explain how the pieces fit, especially on stairs, complex roofs and assemblies. They usually sit on the cover sheet or next to the plans they explain. They are rarely dimensioned and are not meant to be measured. See our own example of an axonometric below.

How a set of architectural drawings is organized

A drawing set is not a pile of sheets. It is ordered so you can find any drawing from any other one. Most US offices use, or loosely follow, the Uniform Drawing System in the United States National CAD Standard (NCS), published by the National Institute of Building Sciences. A sheet number like A-101 has three parts:

So A-101 is the first architectural plan sheet, A-201 the first elevation sheet, A-301 the first section sheet, A-501 the first sheet of details and S-101 the first structural plan.

Not every office uses those digits. The villa used for several examples in this article simply numbers its sheets in sequence, but in the same order. Its sheet list runs: A100 cover, A101 site and location plan, A102 area calculation, A103 basement, A104 ground floor plan, A105 first floor plan, A106 roof plan, A107 and A108 elevations, A109 and A110 sections, A114 glazing calculation and A115 door and window schedule. The order is the same in most sets: the context first, then the plans from the bottom up, then the elevations, sections, details and schedules.

Every sheet also has a title block, usually down the right side or along the bottom. It gives the project, the sheet title and number, the scale, the date, who drew and who checked it, and a revision table. When two people disagree about a drawing, the first question is which revision each of them is looking at.

Architectural drawings by project phase

The set does not appear all at once. In the US the phases are usually the ones in the AIA owner-architect agreement, and each phase produces a different kind of drawing:

Each step adds sheets. A schematic design for a house fits on a handful of sheets; its construction set, with the engineers' drawings, runs to dozens.

Architectural drawings vs construction drawings vs blueprints

These three terms get mixed up all the time, including by people in the industry:

• Architectural drawings are the architect's sheets, the A-series: plans, elevations, sections, details and schedules.
• Construction drawings, or construction documents, are the whole coordinated package used to permit, bid and build: architectural drawings plus civil, structural, mechanical, electrical and plumbing drawings and the written specifications.
• Blueprints are, strictly, copies made with the cyanotype process John Herschel introduced in 1842: white lines on blue paper. The process was replaced by diazo whiteprints and then by plotters and PDFs, but "blueprints" has stuck as the everyday word for any set of building plans.

So "what are architectural blueprints?" has a simple answer: architectural drawings, in an old word.

How to read architectural drawings

If you have a set in front of you for the first time, read it in this order:

1. Cover and G-sheets first. The sheet index tells you what exists. The symbols and abbreviations sheet tells you what the marks mean in this office.
2. Check the scale and north arrow on every sheet. Sheets are rarely all at one scale, and a drawing marked "not to scale" means exactly that. Use the written dimensions, never a ruler on a print.
3. Read the plans, using the grid. The lettered and numbered grid lines (A, B, C across; 1, 2, 3 down) run through every plan, elevation and section. "Grid C/4" means the same point on every sheet.
4. Follow the markers. A circle split in two, with 3 over A-301, means "drawing 3 on sheet A-301". Section markers add an arrow for the direction you look. Elevation markers on the plan point at the face being drawn. Door and window tags point into the schedules.
5. Read the line weights. Heavy lines are what the plan or section cuts through. Medium lines are edges seen below or beyond. Dashed lines are hidden or above. Hatching marks a material: concrete, masonry, insulation, earth.
6. Look for the clouds. A cloud drawn around part of a drawing, with a triangle and a number, marks a change in that revision. Check it against the revision table in the title block.

This walkthrough of a complete residential set, by 30X40 Design Workshop, shows how plans, schedules and specifications work together on a real project:

What's in my set of architectural documents? (30X40 Design Workshop, 19:16)

What's in my set of architectural documents? Sharing everything: drawings, schedules, + specs., by 30X40 Design Workshop on YouTube, 19 minutes 16 seconds. The player only loads when you press play.

One model, four drawings: how BIM produces them

Plans, elevations and sections used to be drawn separately, so changing one meant redrawing the others, and the mismatches between them were a big source of site problems. In BIM software they are no longer separate drawings. They are views of one 3D model. A plan is a horizontal cut through the model, a section is a vertical cut, an elevation is the model seen square-on, and a schedule is a table read from it. Move a wall and every view moves with it.

To show this is not just marketing, we took one IFC4 model our AI engine produced, a single-storey house of 113 m² (about 1,217 sq ft), and drew four views from it with a short Python script. The plan and the section are real cuts: every triangle of every wall, slab, door and window is sliced by the cut plane, and the cut edges are rebuilt into the black shapes you see. The grid lines, dimensions, door swings and level markers are placed from the model's own coordinates too. Nothing was drawn by hand.

One IFC file, four drawings: a plan cut 1.2 m (about 4 ft) above the floor, the south elevation, section A-A along the red line, and an axonometric. The same grid bubbles appear in the plan, elevation and section, which is how you find one point across sheets. Room names and areas come from the model's IfcSpace entities: 113.1 m², or about 1,217 sq ft.

What this does not give you is everything a construction set needs. There are no door and window tags, no material hatching, no notes and no title block, and the house is a schematic-level model: its walls are single solids, so there are no layers to show in a wall section. The office-grade drawings earlier in this article still take an architect hours of annotation per sheet. Getting the model right is the part a tool can speed up most. If you want to see how an IFC model is structured inside, we opened one line by line here.

Sources

• United States National CAD Standard, Version 6, National Institute of Building Sciences: the Uniform Drawing System behind A-101 style sheet numbers.
• Architectural drawing, Wikipedia: drawing types, conventions and history.
• Blueprint, Wikipedia: the cyanotype process introduced by John Herschel in 1842 and what replaced it.
• Shop drawing, Wikipedia and As-built drawing, Wikipedia.
• 30X40 Design Workshop, What's in my set of architectural documents? (YouTube, 2021).