Walls, Floors, Roofs, and Basic Architectural Modeling

Walls, Floors, Roofs, and Basic Architectural Modeling in Revit

Revit is a Building Information Modeling (BIM) platform. Unlike AutoCAD, where you draw lines to represent walls, Revit stores actual building elements—walls, floors, roofs—with real properties such as material layers, thickness, and structural function. Every element you place is part of a coordinated model that drives plans, sections, elevations, and schedules simultaneously.

The Revit Project Environment

Before placing any element, confirm your active level. In Revit, a Level is a horizontal reference plane (Floor 1, Roof, etc.) that governs the height constraints of walls, floors, and roofs. Open the Project Browser on the left panel; double-click Floor Plans → Level 1 to make it your active view before drawing.

Always save a local copy of the starting file before making changes. Use File → Save As and include your initials in the file name. Never overwrite the instructor's original file.

Placing Exterior Walls

Activate the Architecture tab → Build panel → Wall tool. The Type Selector in the Properties palette lists every wall family loaded in the project. For this lab, select Basic Wall: Exterior – Brick on CMU. This composite wall type includes a face brick wythe, air gap, CMU backup, and interior finish—a common exterior assembly for commercial and institutional construction.

Set the Base Constraint to Level 1 and the Top Constraint to the specified floor-to-floor height. Draw the four walls of the 30-ft × 40-ft enclosure by clicking corner points. Use the Temporary Dimension that appears as you draw to hit the correct distance, or type the value directly on the keyboard before committing the segment. Close the loop so all four walls join at the corners. Revit will clean up the corner joins automatically for walls of the same family.

After placing walls, select one and check the Properties palette to confirm Base and Top constraints, wall type name, and location line (usually Finish Face: Exterior for exterior walls). Use the Align tool (Modify tab → Align) to line up wall faces with reference planes or grid lines if needed.

Drawing the Floor Slab

Go to Architecture → Build → Floor → Floor: Architectural (or Floor: Structural depending on your template). Revit enters Sketch Mode, where you draw the boundary of the slab using the Boundary Line tool. Trace the interior face of the exterior walls—Revit provides the Pick Walls option that automatically offsets the boundary to the core face.

In the Type Selector, choose or edit a floor type with a 6-in concrete structural layer. To verify: select the floor type and click Edit Type → Edit (Structure) to inspect the layer stack. The structural layer should show Concrete, Cast-in-Place at 6 inches (0′-6″). Click Finish Edit Mode (the green checkmark) to generate the slab. Revit will ask whether to attach walls to the floor; accept if your walls should sit on top of the slab.

Open the Properties palette with the floor selected and confirm the Level is Level 1 and Height Offset from Level is 0′-0″ unless the design specifies otherwise.

Adding a Flat Roof

Go to Architecture → Build → Roof → Roof by Footprint. In Sketch Mode, draw the boundary matching the exterior wall perimeter. To make it flat, select all boundary lines and uncheck Defines Slope in the Options Bar. Set the slope to 0 (or leave the slope definition off entirely). Choose a flat roof assembly from the Type Selector. Finish the sketch and confirm the Base Level and Offset put the roof at the correct height above your walls.

Auditing the Model with Measure and Align

Use the Measure tool (Modify tab → Measure panel → Measure Between Two References) to check critical dimensions. Click two wall faces; the distance appears in the dialog. Compare every measured value to the dimensioned floor plan PDF. The pass threshold for this lab is 1/8 inch (0′-0 1⁄8″).

If a discrepancy exists, select the wall, activate Move or drag an end grip, and reposition. Add a Revision entry: in the Project Browser under Sheets, right-click a sheet and select View Properties → Revisions on Sheet, or create a Revision Cloud annotation in the affected view noting the correction made.

Workspace Safety

This lab is computer-based; physical hazards are limited but real. Ergonomics matter for sustained CAD work: adjust your chair so your elbows are at approximately 90°, your monitor is at eye level, and your wrists are neutral on the keyboard. Take a short break every 50–60 minutes to reduce repetitive-strain risk. Secure loose cables under the workstation so they do not create a trip hazard. If you print the reference floor plan on a large-format plotter, wait for the machine to finish before retrieving the sheet—the print head and heated rollers can cause burns. Never defeat or bypass the plotter's safety guards.

Saving and Submitting

Save the file frequently using Ctrl+S. Before submission, run File → Audit to check for model corruption. Submit the .RVT file to the designated folder. The instructor will open the file, inspect wall type and floor type via the Properties palette, and measure three key dimensions with the Measure tool. All three must be within 1/8 inch and the correct types must be applied to earn a pass.