Revit

Strip footing family in Revit: stepped section, length per run

Strip footing family in Revit 2027: build an inverted T section, add size and material parameters, give each run its own length, compare Wall Foundation.

  • TS. Nguyễn Mạnh Tuấn
  • 15 min read
A self-built inverted T strip footing running along grid A, next to Revit's built-in wall foundation under the wall on grid B Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Most people searching for strip footings are really looking for a ready-made file: a CAD drawing of a strip footing for a two-storey house, an Excel design sheet, or a family someone has shared. A borrowed file usually fits exactly one project, and the next project means editing it by hand.

A strip footing family in Revit takes a different route: build a parametric section once, and let every footing run carry its own length. This article walks through fifteen steps in Revit 2027, from the foundation template to placing footings along a grid, and compares the result with the built-in Wall Foundation tool. For a full course on building component libraries, the Institute runs a Revit family creation course.

What a strip footing is made of

A strip footing runs along a line, under a row of columns or under a load-bearing wall. The section most often seen in Vietnamese drawings is an inverted T: a wide base slab at the bottom and a narrow rib on top that ties into the column bases. Some projects chamfer the slab edges into a trapezoid.

Because it runs along a line, a strip footing differs from a pad footing in one respect: the section stays the same while the length changes from run to run. A good family keeps the two apart. Section sizes belong to the type; length belongs to each placed footing.

Figures in this article, such as a 1,200 mm slab and a 300 × 500 mm rib, are example values for modelling, not design values. Real sizes come from each project's calculations.

Before you create a strip footing family in Revit

You need Revit 2027 with the metric family templates, including Metric Structural Foundation.rft, and a project with a grid to place the footing in. It helps to read how to create a family in Revit first for the principle of tying geometry to reference planes; this article covers only what is specific to footings.

This article is part of the Institute's Revit Structure series.

Building the strip footing parameters

Step 1 — Open the metric foundation template

Go to File › New › Family. The template dialog opens in the English-Imperial folder, the inch-based set.

1 Look in switched to the English folder. 2 the foundation template file name. 3 the Open button Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Switch to the English folder next to it, select Metric Structural Foundation.rft and click Open. Every metric template name starts with Metric.

Step 2 — Check the category and the starting frame

The Family Editor opens in the Ref. Level plan with two reference planes crossing at the origin. The type selector in the Properties palette reads Family: Structural Foundations, so the category is already right and needs no change.

1 the Forms panel on the Create tab. 2 the Family Types button. 3 the Structural Foundations category. 4 the two reference planes crossing at the origin Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Click Family Types on the Properties panel to see the starting parameters: Structural Material, Foundation Thickness, Length and Width. These four come with the foundation template. Length is a built-in type parameter that cannot be switched to instance, so it is not used for the footing length.

Step 3 — Draw the reference planes at both ends

Choose Create › Datum › Reference Plane, pick Pick Lines on the Draw panel and type 1500 in Offset. Hover next to the vertical centre plane, slightly to the left, and click: Revit creates a parallel plane 1,500 mm away. Repeat on the right.

These two planes are the footing ends. The same way, set Offset to 600 for the two slab edges and 150 for the two rib edges, each taken from the horizontal centre plane.

Step 4 — Dimension and add the length parameter

Type DI, click the left end plane, the centre plane and the right end plane, then place the dimension line. Select that string and click the EQ symbol so the two halves always stay equal. Add one overall dimension from end to end.

1 overall dimension labelled Chieu_dai. 2 EQ string keeps the footing symmetric. 3 slab dimension labelled Width. 4 rib dimension labelled b_suon Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Select the overall dimension and, on the Label Dimension panel, click the create parameter button just right of the Label box. The Parameter Properties dialog opens.

1 Family parameter, the kind that cannot appear in schedules. 2 parameter name typed without diacritics. 3 Instance selected Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Name it Chieu_dai, meaning length, choose Instance and click OK. This is the key decision: an instance parameter lets every footing in the project have its own length while sharing one section type.

Step 5 — Assign Width and b_suon to the section

Repeat for the two slab edges: an EQ string through the centre plane, then an overall dimension. This time do not create a new parameter; open the Label list and pick the existing Width.

For the two rib edges, create a new parameter b_suon, rib width, and leave it as Type. The plan now carries three labels, Chieu_dai, Width and b_suon, as in the image in step 4.

Step 6 — Set the rib and slab levels

Open the Left elevation from the Project Browser. Use Reference Plane › Pick Lines with Offset 500 and click the Ref. Level line from below to get the rib bottom; then Offset 300 on that new plane for the footing bottom.

1 the Label box set to h_suon, the list showing every parameter with its value. 2 rib height dimension. 3 slab thickness dimension Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Dimension from Ref. Level to the rib bottom and assign a new parameter h_suon, rib height. Dimension the slab thickness and assign the existing Foundation Thickness. The top of the footing sits on Ref. Level, so once placed in a project, the rib top matches the level.

Modelling the stepped section

The inverted T section is made of two Extrusion solids drawn in the Left elevation, each one a rectangle: one for the slab, one for the rib.

Step 7 — Choose the work plane

Still in the Left elevation, click Create › Forms › Extrusion. Revit asks for a work plane in the Work Plane dialog.

1 Name selected with the Center Left/Right plane. 2 the OK button Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Choose Name, pick Reference Plane : Center (Left/Right) and click OK. The solid extrudes perpendicular to the elevation, which is along the footing; its two ends are locked in step 10.

Step 8 — Draw the slab and lock its four edges

On the Draw panel pick the rectangle tool. Hover over the intersection of a slab edge with the footing bottom, wait for Revit to show Intersection and click; click the opposite corner where the other slab edge meets the rib bottom.

When the rectangle is done, Revit shows an open padlock beside every edge that lies on a reference plane. Click each one to close it. Padlocks for the vertical edges sit on the visible part of the plane, sometimes well above the shape, and are easy to miss.

If no padlock shows, use Align: type AL, tick Lock on the ribbon, click the plane first and then the sketch edge. Click the green tick Finish Edit Mode to finish the slab.

Step 9 — Draw the rib as a separate Extrusion

Click Extrusion again and choose the Center (Left/Right) plane if Revit asks. Draw a rectangle from a rib edge at the rib bottom up to the other rib edge at Ref. Level.

1 the rectangle tool on the Draw panel. 2 the rib rectangle with the padlocks of its horizontal edges. 3 the padlocks of its vertical edges higher up Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Lock all four edges and click Finish Edit Mode. With the rib as its own solid, each solid has only four edges to lock and checking is easier.

Step 10 — Lock both ends to the end planes

Go back to the Ref. Level plan. Both solids are now only 304.8 mm long, running from the centre plane to the right. Use Align with Lock: click the right end plane, then the end face of the slab; repeat for the rib and for the left end.

1 the closed padlock at the left end. 2 both solids now run the full distance between the end planes Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

The left end lies on the centre plane, so a click often picks the plane. Hover over the edge and press Tab until the tooltip reads Extrusion before clicking.

Step 11 — Assign the structural material

Select the slab solid, find the Material row in the Properties palette and click the small button at the end of the row. The Associate Family Parameter dialog opens.

1 the Material row of the solid with the associate button at its end. 2 the Structural Material parameter of the foundation category Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Choose Structural Material and click OK. Do the same for the rib. Both solids now follow one type parameter, so in the project you pick the concrete grade once.

Step 12 — Join the slab and the rib

Go to Modify › Geometry › Join, click the slab and then the rib. The two solids become one, and the line between them disappears in sections and 3D.

The inverted T footing in the Family Editor 3D view after joining the slab and the rib Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Testing the family and placing strip footings in Revit

Step 13 — Create types and flex them

Open Family Types, click the first new type button to the right of Type name; the Name dialog appears. Name the type by size, for example MB 1200x800. Add a second type MB 1500x950 and change its values.

1 type MB 1500x950 selected. 2 the six size parameters after the test values. 3 the Apply button Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

The test type uses a 1,500 wide, 350 thick slab, a 400 × 600 rib and a 6,000 length. Click Apply: the footing doubles in length while the section stays symmetric and both ends stay on their planes. Anything that does not follow is not locked.

Step 14 — Save and load into the project

Save the file as .rfa, named with your office's library prefix. Click Load into Project on the Family Editor panel. With several projects open, the Load into Projects dialog lists them so you can tick the target.

Step 15 — Place the strip footing along a grid

Open the structural plan of the foundation level and go to Structure › Foundation › Isolated. Choose the type in the type selector and type the length in the Chieu_dai row of the Properties palette before clicking.

1 the Modify, Place Isolated Foundation tab. 2 the strip footing family and type selected. 3 length 9000 typed before placing. 4 the footing preview following the cursor Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

In the example, grids 1 and 3 are 8,000 apart and the footing extends 500 past each, so Chieu_dai is 9,000. Click the intersection of grid 2 and grid A: the footing is centred there and runs along grid A. For a footing along grids 1, 2 or 3, press Space to rotate before clicking.

The Properties palette of the placed footing shows Elevation at Bottom −950, the 350 + 600 total height of type MB 1500x950. Reinforcement follows in column and foundation reinforcement, and concrete volumes in concrete quantities in Revit.

Wall foundation or a custom family: which to use

Revit has a built-in footing under walls: Structure › Foundation › Wall, choose a type in the type selector and click the wall. The footing follows the wall and grows when the wall grows. Autodesk's page Create a Wall Foundation states that it supports a bearing or retaining wall.

1 the self-built inverted T footing along grid A. 2 the built-in wall foundation under the wall on grid B Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering

Edit Type on the wall foundation shows its limit: the section is a single rectangle defined by Width and Foundation Thickness.

1 Wall Foundation is a system family. 2 Structural Usage set to Bearing. 3 width and thickness only Photo: Screenshot of Revit 2027, Institute of Information Technology in Civil Engineering
SituationUse
Footing under a load-bearing wall, rectangular sectionWall Foundation, quick and follows the wall
Footing under a row of columns, no host wallA custom strip footing family
Inverted T section with a rib or chamferA custom strip footing family
You want to draw the footing with two clicks like a beamA path-based family, see below

The second way to make a footing follow a line is to start from the beam template Metric Structural Framing - Beams and Braces.rft, change the category to Structural Foundations in Family Category and Parameters, and model it with Sweep. The footing is then drawn with two clicks, like a beam. The section can be split out into a Profile family from Metric Profile.rft and reused across families.

When the strip footing family does not work

SymptomCauseFix
Changing Chieu_dai leaves the footing at its old lengthSolid end faces are not locked to the end planesAlign the plane, then the end face, and click the padlock
Changing b_suon shifts the rib to one sideNo EQ string through the centre planeDimension the three planes and click EQ
Every footing of a type has the same lengthThe built-in Length is a type parameterCreate a separate instance parameter for length
Changing h_suon raises the rib but the slab does not dropThe rib bottom or slab top edge is not locked to the rib bottom planeLock both edges to the same plane
Nothing appears after placing, and a warning says None of the created elements are visibleWorking in an architectural plan, the footing is below the view rangePlace footings in the structural plan of the foundation level
Wall Foundation offers nothing to click under a row of columnsThe tool only accepts a wall as hostUse a custom family under columns

Four common misconceptions

What people sayWhat Revit 2027 actually does
A footing family must be switched to the foundation categoryThe Metric Structural Foundation template is already Structural Foundations
The built-in Length parameter is the strip footing lengthLength is a built-in type parameter and cannot be made instance
Wall Foundation covers every kind of strip footingIt only supports walls, with a rectangular width by thickness section
Strip footings have to be modelled In-PlaceA family is reusable in any project; an in-place element lives in one file

In short, a strip footing family in Revit is worth building when the footing runs under columns or has a stepped section; a rectangular footing under a wall is covered by the built-in Wall Foundation.

Frequently asked questions

Can I just download a strip footing family?

Many sites share them, but a downloaded file has to be opened and checked: is the length a type or instance parameter, which unit system does it use, is the geometry locked to planes. Building it with the fifteen steps above means you know every parameter and can reuse it on every project.

Why should the strip footing length be an instance parameter?

With the same section, each footing run has a different length. An instance parameter keeps one type such as MB 1200x800 for the whole building while each run gets its own length.

Should a footing under a wall use Wall Foundation or a custom family?

For a rectangular section under a load-bearing wall, use Wall Foundation for speed. With a rib, a chamfer, or a run under columns, build a custom family.

Can a strip footing family be scheduled for concrete volume?

Yes. It belongs to Structural Foundations and has Volume, so a foundation schedule reads the volume of every run directly. Chieu_dai is a family parameter and does not appear in schedules; use a shared parameter if you need a length column.

About the author

TS. Nguyễn Mạnh Tuấn — BIM lecturer at the Institute of Information Technology in Civil Engineering, Hanoi University of Civil Engineering