Prefabrication and the enabling methodology of Design for Manufacture and Assembly (DfMA) are growing rapidly, and is further fueled by COVID-19. McKinsey forecasts that 45% of the entire AEC value chain — worth $13 trillion dollars — will shift away from traditional processes in the next 15 years.
The industry is clearly moving more towards Industrialized Construction including prefabrication and the enabling design methodology, DfMA, but executing remains a hurdle for many firms. As Amy Marks, Autodesk’s Head of Industrialized Construction Strategy and Evangelism, and recognized as the Queen of Prefab, puts it, “Industrialized Construction is about more than just embracing it — it’s about level setting on what it actually means. It isn’t just about manufacturing techniques in construction. It’s about integrating the processes, workflows, and data of construction, manufacturing, and operations into design.”
However, there are certain practices within the design and estimating process that can either enable or constrain prefabrication — one of them being target value design.
This is exactly what Marks will discuss in her keynote session at the upcoming Design-Build Conference & Expo.
Titled DfMA, Prefabrication, and Element-Centric Target Value Design, this session will discuss what happens to the collaborative process between designers, builders, suppliers, and estimators when architects use DfMA principles and prefabrication. Marks will discuss the roadblocks and issues that may come up in the process, and what construction professionals should do to address them.
Ahead of the conference, we chatted with Marks and asked her to share the three of the most important things to keep in mind when implementing target value design and prefabrication.
1. Understand the Elements Upfront
Target value design (TVD) is a practice in which the cost to build something is determined before the design phase. So instead of coming up with an estimate based on an existing design, you’ll create a design based on an estimate.
Construction professionals typically implement TVD in a trade-centric way. But according to Marks, this practice could prevent you from achieving cost certainty and ultimately hinder you from utilizing prefabrication.
“When they started doing target value design, it was all by trade. So there’s a target cost for electrical. There’s a target cost for plumbing. There’s a target cost for HVAC,” she explains.
While doing TVD in this way can provide certainty around your trade estimates, it makes implementing prefabrication more difficult, especially multi-trade assemblies.
So, rather than taking a trade-centric approach to target value design, Marks says it’s far more effective to be element-centric, where you look at the different elements or “chunks” of the building (e.g., riser, rack, headwall, central utility plant,etc.) and target costs based on those elements.
“We should move towards element-centric target value design. This means after you’ve determined the program needs, you need to understand the elements of what you’re building, and you need to do that before benchmarking historical costs and decoupling scope,” she says.
“Immediately after understanding the program, you should ideate and decouple the elements upfront.”
Marks recommends carving out the building into different chunks.
“You have to say, ‘That’s a central utility plant, we’re going to prefabricate that’ or ‘That’s a bathroom, we’re going to use pods for those.’”
“Then those become their own target costs with their own scope, instead of being interwoven with plumbing, electrical and the structure. That’s being element-centric. It’s thinking about things as the assembly of pieces and parts instead of by trade.”
2. Don’t Taint the Pool of Your Supply Chain Partners
According to Marks, you should recognize that your current supply chain may not be the supply chain you need when implementing TVD with an element-centric approach.
The way that you approach your supply chain partners will change if you decide to take an element-centric approach instead of a trade-centric one. One of the reasons why it’s difficult to do prefabrication with trade-centric TVD is that tradespeople will work on their assignment with the whole building in mind.
If you have a target cost for plumbing, for example, then the partner in charge of plumbing will work based on that cost. Now if you decide to go with a prefabricated bathroom, you simply cannot go back to your plumbing partner and tell them to exclude the bathrooms and give you credit back for that specific building element.
Marks likened it to washing a white shirt with a red sock — this practice taints the whole pool.
“The second you go out with trade-centric target value design scopes, it’s like washing a white shirt with a red sock. You can never go back, it will always be some shade of pink. The tradesperson can never unsee what he or she could have had in money and scope.”
You can avoid that scenario by understanding each element’s scope and cost upfront, while managing your supplier communications and relationships.
“In element-centric target value design, you have to carve out all these elements upfront and never give them out to the trades that aren’t making them. A bathroom pod is a bathroom pod. If you’re pricing the rest of the plumbing, you’re not pricing the plumbing in that bathroom, ever.”
She adds, “Unless you do this upfront, and unless you define the elements prior to understanding benchmarking historical costs, it’s very difficult to implement prefabrication with target value design.”
When finding or managing supply chain partners, it may behoove you to find trusted and neutral partners who can advise and help you pave the way forward. Marks also gives a nod to MEP subcontractors who have extensive fabrication experience, some of which are already implementing prefabrication to great success.
3. Don’t Overanalyze
Marks’ last piece of advice? Stop overanalyzing.
“The questions are often something like ‘Should we prefabricate? Should we not?’ Stop with all the analysis paralysis. We know prefabrication provides certainty and safety. It’s a defined scope, it’s built inside in a controlled environment and creates better flow on the jobsite,” says Marks.
“Decouple the elements of the project, understand that you can’t taint the supply chain pool, and that you’re probably going to have to work with new partners. Stop analyzing. Once you understand that you have an element that hits the target cost, go. Just do it.”
Learn How to Implement Element-Centric Target Value Design
Prefabrication will play a major role in construction going forward. You need to be prepared and learn how you can best implement the practice in your project.
So, don’t miss your chance to hear from Amy Marks at the upcoming Design-Build Conference & Expo. Register today and gain insights from the Queen of Prefab herself!
Interested in learning more about Autodesk’s role in industrialized construction? Follow Amy on LinkedIn, Facebook, Twitter, Instagram, and TikTok in addition to Autodesk Construction Solutions. You can also join the conversation using #IndustrializedConstruction #industrializedrevolution #DfMA #QueenofPrefab.