5D BIM: BIM & Estimating

As the construction industry continues to adopt building information modeling (BIM), 5D BIM is emerging as a tool to enhance project cost estimation and management. Building on the foundations of 3D BIM, which focuses on the geometric aspects of design, and 4D BIM, which integrates scheduling data, 5D BIM introduces the dimension of cost.

5D BIM allows construction teams to develop precise cost forecasts that align closely with project requirements — significantly streamlining the estimation process. With this added BIM dimension, teams gain a valuable tool for generating bills of materials, controlling costs, and more. This article will discuss how 5D BIM works, including an in-depth look into its benefits and best practices for implementation.

How 5D BIM Works

5D BIM incorporates cost data by tying that data to individual elements in the BIM model. 

In an ideal world, existing systems work together to enable this effort. Say a model gets built using the company’s database of parts and pieces. If those components get tied to the company’s cost catalog, it makes it easy for the team to estimate project costs. 

General contractors (GCs) can leverage the now-5D model to automatically generate a bill of materials, for example. Or trade partners can use the model to see how much a full section of ductwork will cost. 

Construction professionals usually won’t have an overarching federated model for the project loaded with cost data. Instead, 5D BIM gets deployed internally to create or validate estimates. That’s true whether the company adds cost data to an externally created model or does their modeling in-house. 

In short, teams don’t want to share the cost-loaded 5D model with external stakeholders to protect their proprietary pricing information. If an electrical contractor is seeing savings by buying lighting components in bulk, for example, they don’t necessarily want to advertise that they’re pocketing that added profit margin. 

5D BIM Maturity Levels

Not all 5D BIM is created equal. Some 5D models only include the cost data for materials. Only companies with a higher level of BIM maturity — like those with an internal virtual design and construction (VDC) branch — add labor data, too. The deeper the granularity the firm applies to the model, the more accurate it becomes as a cost estimation tool.

If a specialty contractor applies historical cost data for materials, for example, the model can help them generate rough pricing. Connecting it to their current cost catalog delivers better costing insights, though. And having a way to overlay the labor element based on how much time individual components take to install makes the model much more effective. It helps to solidify that key piece of pricing a project. 

The same is true for the model itself. If the contractor uses the model created during the architectural design process intended to show design intent, overlaying cost data generally yields squishy estimates. But if the firm adapts that model or creates their own to factor in their own insights in areas like constructability, cost-loading that model yields more reliable estimates. 

In other words, as contractors get more sophisticated in model development and attaching up-to-date cost data, 5D BIM moves from a rough estimation tool to a detailed, insight-yielding way to predictably price projects. 

4D vs. 5D BIM

Some companies move linearly in their BIM maturity from 3D models to 4D ones to models with 5D cost data attached. Others skip straight from 3D to 5D BIM. That works because the fourth dimension in BIM is actually a distinct category.

4D BIM entails overlaying scheduling data on the model. By modeling the construction of the project over time, it enables better sequencing. Like 5D, 4D BIM is useful for project planning and risk mitigation. Firms don’t necessarily need to deploy the fourth dimension to get valuable costing insights from a 5D model, though. 

In both instances, as technology advances and makes it easier to create models and load in 4D and 5D data, more and more companies are exploring these added dimensions of BIM. Looking forward, it’s likely that any firm doing 5D BIM will eventually deploy 4D BIM, and vice versa. 

Benefits of 5D BIM

It’s a notable lift to add the fifth dimension to building information modeling. Still, many companies are putting in this effort, in some cases even hiring dedicated BIM managers to do so. However, there can be a lot of return on investment from this effort.

More Accurate Project Pricing

By automatically attaching costs to the individual components required on a project, 5D BIM can generate accurate project costs as easily as teams have historically created rough orders of magnitude. It gets down to a granular level of detail without requiring an individual to do that digging, enabling more accurate pricing much more quickly. 

Data-informed Value Engineering

When the model has cost data attached, showing how changes impact the budget gets fast, easy, and particularly effective. The owner can quickly see how swapping a finish will affect both the look of the finished project and the bottom line. This enables stronger value engineering while protecting the overall design intent. 

Better Risk Management

Because attaching cost data to the model eliminates a lot of the guesswork in pricing a project, it helps teams remove some of the risk they take on. Budget discrepancies can contribute to conflict and lead to delays. When contractors can align the cost of the project with the owner’s budget more precisely, they notably lower the risk of a big gap there, which could mean an ongoing push-and-pull with the owner.

More Efficient Takeoffs

With 5D BIM in play, teams can deploy automated 3D takeoffs complete with cost information. This doesn’t just save time. It also eliminates the risk for human error that arises during the often tedious work of manual takeoffs. The model powers quick, accurate cost takeoffs. 

Change Order Support

If a change order arises on the project, a cost-loaded model allows teams to provide more accurate pricing on the time and materials required for that change. Rather than rough numbers, they can change out the elements in the model to arrive at more precise estimates.

When specialty contractors can deliver this level of detail quickly and accurately, the GC can pass that onto the owner. With everyone on the same page about what the change requires, making decisions — and reducing delays — gets easier.

Avoidance of Fee Erosion

5D BIM helps contractors protect their fee from the start. By enabling more accurate quoting, it helps them build in the appropriate fee (i.e., avoid underbidding). As the project moves forward, 5D BIM supports better risk and change order management, helping contractors avoid situations that could eat into their fee. Because the contractor can continually update project costs as the project evolves, they can make adjustments as needed to protect their profit margin. 

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Best Practices for 5D BIM

For companies that want to unlock the advantages of 5D BIM, there are a few best practices to be considered.

That begins with clean, reliable cost data. The company should develop a cost catalog database that can load pricing and labor data into their modeling platform of choice. Someone should be tasked with routinely going through and updating pricing and labor rates as needed. 

Then, the company needs to be able to trust the model onto which they’re loading that cost data. That could mean working on BIM management internally or adapting the design model to their needs. In any case, they need a process to validate the model so it becomes a reliable foundation for their cost projections. 

Finally, the 5D model shouldn’t just be created at the start of a project, then left alone. By continuously updating the cost data in the model to reflect the project’s progress, the model maintains its usefulness. Comparing pricing projections completed at the beginning of the project to actual costs at the end helps teams refine their 5D BIM processes. This, in turn, moves them toward faster, more accurate costing for use on future projects.

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