Creating a complete building model in Revit is a process of building up from the ground: you establish the vertical structure with levels and grids, model the enclosing elements — walls, floors, and roofs — and then add openings, stairs, and internal partitions. The order matters because Revit elements relate to one another: a floor is bounded by walls; a roof sits on top of walls at a specific level. Understanding these relationships and the correct modelling sequence helps you avoid the rework that comes from building in the wrong order. This guide takes you through the complete process of creating a basic building shell in Revit 2026.
Step 1: Set Up Levels and Grids
Before placing any building elements, establish the project’s vertical datum (levels) and the structural grid. Open an Elevation view from the Project Browser.
Editing Levels
The default template provides Level 1 and Level 2. Rename these to match your project — Ground Floor and First Floor for a two-storey house, for example. Click on a level name to rename it in-place. Adjust heights by clicking on the level elevation value and typing the correct height in millimetres.
Add additional levels as required using Architecture > Datum > Level. Draw each level line across the full width of the building section. Revit automatically creates a corresponding floor plan view for each level you add. Consider creating a Roof Level even if it is simply a reference for wall tops — it gives you a clean constraint to tie wall heights to.
Setting Up Structural Grids
For buildings with a defined structural grid, place grid lines using Architecture > Datum > Grid. Draw vertical grids (numbered 1, 2, 3…) and horizontal grids (lettered A, B, C…) at the correct spacing. Grid bubbles appear at the ends of grid lines and display in all plan, section, and elevation views — providing a consistent spatial reference across the entire drawing package.
Step 2: Model External Walls
Open the Ground Floor plan view. Go to Architecture > Build > Wall > Wall: Architectural. Select your external wall type from the Type Selector. If a suitable type does not exist, create one (covered below).
Creating a Wall Type for UK Construction
In the Properties Palette, click Edit Type, then Duplicate. Name the new type accurately — for example “EW-01: Brick/Cavity/Block 300mm”. Click Edit next to the Structure field to open the Edit Assembly dialog. Here you define the wall layers from exterior to interior:
- Finish 1 [4] — Brick, nominal 102.5mm
- Thermal/Air Layer [3] — Cavity with insulation (PIR), 100mm
- Core Boundary [—]
- Structure [1] — Dense blockwork, 100mm
- Core Boundary [—]
- Finish 2 [5] — Plaster/render, 13mm
Assign materials to each layer by clicking in the Material column. Revit’s material library includes brickwork, blockwork, insulation, plaster, and hundreds of other materials, each with visual appearance settings, thermal properties, and structural properties.
Drawing the External Wall Outline
With the wall type selected, set the following parameters in the Properties Palette:
- Base Constraint: Ground Floor (Level 1)
- Base Offset: 0mm (or -450mm for a foundation starting below ground)
- Top Constraint: Up to level (select First Floor or Roof Level)
Draw the external wall outline by clicking to set corner points. Press Escape to finish. Revit automatically cleans wall junctions at corners. Check the 3D view to confirm the walls are rising to the correct height.
Step 3: Add Internal Walls
Repeat the wall placement process using appropriate internal partition types — typically 100mm dense blockwork for structural partitions or 100mm lightweight steel stud partitions for non-loadbearing internal walls. Set the Base and Top constraints to the surrounding floor levels. Draw internal walls connecting to the external wall faces, and Revit handles the junctions.
Step 4: Place Floors
Floors in Revit are sketch-based elements — you draw the boundary shape and Revit generates the floor slab. Go to Architecture > Build > Floor > Floor: Architectural. The view switches to sketch mode. You need to draw a closed boundary representing the perimeter of the floor.
Use the Pick Walls option: click the Pick Walls button in the Ribbon, then click each external wall in turn. Revit extracts the internal face of each wall as the floor boundary, automatically creating the correct floor extent. Alternatively, draw the boundary manually using lines and arcs.
In the Properties Palette, select the floor type — for a ground floor concrete slab: “Floor: Concrete 150mm on Insulation” would include a screed finish, insulation layer, and structural concrete layer. For an upper floor timber construction, a type including decking, joists, and ceiling finish would be appropriate. Create custom floor types to match your actual specification following the same layer editing process as walls.
Set the floor’s Level to the correct storey. Click the green tick to finish the sketch and generate the floor. If any walls extend below the floor (as typically happens with external walls that continue down to foundations), Revit will prompt you to attach the wall bases to the floor — accept this to avoid gaps in the model.
Step 5: Add Doors and Windows
Place doors using Architecture > Build > Door and windows using Architecture > Build > Window. Each element must be hosted within a wall. Click on the wall face at the desired location to place the element. The rough opening is cut into the wall automatically.
Control the exact position of a door or window by selecting it and adjusting the dimension to the nearest wall face in the temporary dimension display, or by using the Properties Palette to set the sill height (for windows) or threshold level (for doors). Load additional family types from the Revit content library if the default options do not match your design.
Step 6: Create the Roof
Roofs are among the more complex elements to model in Revit, as they must define both plan shape and slope geometry. Three main methods are available:
Roof by Footprint
The most common method for simple pitched and hipped roofs. Go to Architecture > Build > Roof > Roof by Footprint. In sketch mode, draw or pick the roof perimeter. Each boundary line has a Defines Slope parameter — enable this on the lines that form eaves edges, and set the slope angle. Revit calculates the ridge height automatically from the defined slopes.
For a simple gable roof: draw the rectangular perimeter, enable Defines Slope on the two long sides (eaves), and set the slope to 35° (a common UK pitch). The two short sides (gable ends) should have Defines Slope disabled — Revit will create vertical gable walls automatically. Click Finish to generate the roof.
Roof by Extrusion
For mansard, barrel vault, or mono-pitch roofs where the profile needs to be drawn as a cross-section, use Roof by Extrusion. Draw the roof profile in an elevation view and define the extent of the extrusion.
Roof by Face
Used when modelling complex roof forms that have been created as conceptual mass geometry. Apply a roof to any face of a conceptual mass using this method.
Step 7: Attach Walls to Roof
After creating the roof, gable-end walls may need to be extended to fill the triangular area up to the roof slope. Select the gable walls, then go to Modify > Modify Wall > Attach Top/Base. Click on the roof, and Revit automatically trims or extends the wall top to meet the underside of the roof.
Reviewing the Complete Model
Open the 3D view to review the complete building shell. Check that all walls meet cleanly, floors sit at the correct levels, and the roof covers the building correctly. Use Section Box in the 3D view (check the box in the Properties Palette) to slice through the model and inspect internal conditions. Any modelling errors — wall gaps, floor overlaps, or roof misalignments — will be apparent in section.
With the shell complete, you have the foundation for a full building information model — ready to add MEP systems, structural elements, interior fit-out, annotations, and drawing sheets.
If you are ready to begin building BIM models, Revit 2026 is available from GetRenewedTech at £39.99 for one year of full access on Windows.
