Concrete Takeoff from BIM
Concrete is typically one of the largest cost items on any structural project. This article walks through how to extract concrete quantities from a BIM model in Sparkel — walls, slabs, and columns — and turn them into a supplier order or bid package.
The challenge with concrete in BIM models
Concrete elements are usually present in most IFC models, but the quality varies significantly. Walls may be modelled as single layers without material breakdowns. Slabs may overlap at junctions causing double-counting. Column geometry may include reinforcement that inflates volume figures. Sparkel lets you handle all of these by defining exactly what you want to measure, rather than trusting raw model output.
Step 1: Set up the takeoff structure
Create a new takeoff named for your scope — for example, "Concrete structure — bid" or "Ground floor concrete — procurement". Then create items reflecting how you want to present the quantities. A typical concrete takeoff might include:
External walls — m³, split by thickness or concrete class
Internal walls — m³
Slabs — m³, split by floor level if needed
Columns — m³ or pcs
Beams — m³ or m
Foundations — m³
Organising items by trade structure upfront makes the export cleaner and the supplier communication clearer. See The Quantity Table for a full guide to creating and managing items.
Step 2: Link elements using BIM properties
For concrete, dynamic linking is usually the most efficient approach. Open the BIM properties panel by clicking on any concrete element to understand what properties are available. Common properties to filter on:
IfcWall,IfcSlab,IfcColumn,IfcBeam,IfcFooting— IFC element classMaterial name — filter for "concrete", "betong", or a specific class like "C30"
IsExternal— True/False to separate exterior from interior elementsLevel or floor — to split quantities by storey
Set up a dynamic linking rule on each item using the relevant property filter. All matching elements link automatically, and the quantity updates in real time. See BIM Linking for step-by-step instructions on setting up dynamic rules.
Step 3: Handle unreliable geometry with shapes
If certain elements have incorrect geometry — for example, walls modelled without openings subtracted — use shapes to correct or supplement. Draw a 3D shape representing the actual volume you want to measure and link it to the relevant item instead of (or in addition to) the BIM element.
Step 4: Review and verify
Click each item in the table to see which elements are highlighted in the viewer. Check that the right elements are included and that nothing is double-counted at structural joints. Adjust dynamic linking rules or add/remove manual links as needed.
Step 5: Export or send to supplier
Once quantities are verified:
Export to Excel for use in a cost model or bid document
Send to supplier via Sparkel's built-in ordering flow — add your concrete supplier, publish the takeoff, and communicate directly within the platform