AI in Legacy Industries (Part 2): How Trunk Tools is Reshaping Construction End-to-End
Lessons from Dr. Sarah Buchner, CEO and Founder of Trunk Tools
By Claire Biernacki & Cindy Fan, BBG Ventures
The first wave of AI adoption was centered on knowledge work. Now, AI is opening doors in legacy industries, enabling new ways to work in sectors long resistant to change. Construction, a $13T industry that makes up ~5% of US GDP yet remains one of the least digitized, is proving to be ripe for reinvention. At BBGV, we believe the biggest wins happen when AI meets founders with deep domain expertise — founders who are from the field, speak the language of their customers, and solve unglamorous but critical pain points others overlook.
Earlier this month, we shared lessons from Adaptive’s Matt Calvano on bringing AI into construction finance, automating areas like billing, receipt capture, budgets, and reporting. This week, we’re moving from the books to the blueprints: fresh off of raising her $40M Series B led by Insight Partners, Dr. Sarah Buchner from Trunk Tools shared insights with us for founders building in tough-to-crack foundation industries.
Given the complexity of documents and siloed systems across the construction build process, Trunk Tools is tackling the other side of the construction equation: the job site itself. Trunk Tools deploys AI agents that operate in the thick of construction’s daily grind, automating time-consuming and error-prone workflows like document review, drawing analysis, conflict detection, and site communication.
Sarah’s story is also a masterclass in earning trust in a category that didn’t exist when she started, driving AI adoption, and scaling trust in one of the most complex verticals out there. Below is a summary of the insights she shared with us:
1. From Job Sites to Startups: The Importance of Deep Customer Immersion
Sarah started working as a carpenter with her dad when she was 12. She worked her way up in the industry to a group leader, built a construction safety app, and then completed her PhD in civil engineering and data science. Growing up on job sites gave Sarah firsthand insight into the inefficiencies that slow builders down, like paperwork, compliance, and fragmented communication. Her first product, TrunkPerform, aligned incentives and boosted field team productivity (e.g., texting carpenters extra tasks to complete for a bonus). Though that has now been phased out, it built credibility with crews and superintendents, paving the way for them to tackle bigger pain around documentation and communication.
“Entrepreneurship is not about knowing it all, but consistently figuring it out faster and better than anyone else.” But at the same time, she cautions founders to be honest about whether they really have an advantage compared to anyone in YC; without it, breaking into a legacy industry is hard.
Sarah is continuing to learn with her customers though — even today, Sarah spends time in the field every month. As she put it, “You either need to be your customer or be next to your customer deeply. That’s the only way you’ll build something people love.”
2. Why Now: AI Adoption in Construction is Accelerating
Despite construction’s importance to the economy, it has historically lagged in digitization and behavioral change. Sarah sees AI as the unlock: “People are using AI in their everyday lives, whether it’s ChatGPT or image generation, so naturally they start thinking about how to bring those tools to work.”
Trunk Tools frames this as “intelligent augmentation”: it doesn’t mean that “AI is going to take your job, but people who use AI will outperform those who don’t.” AI handles roughly 80% of repetitive tasks, like conflict detection, drafting responses, and pulling context, but relies on humans in the loop for judgment. This balance helps drive adoption while still respecting the complexity of construction and reality that everything can’t be automated end to end.
3. Building in Legacy Industries: Education and Trust as GTM Levers
When Trunk Tools launched, “construction AI” wasn’t even a category. Much of the early GTM was education and trust-building. Sarah and her team ran live workflows side-by-side with field teams, showing value in real time instead of relying solely on demos.
She also made a deliberate choice to hire customer-facing employees with construction backgrounds. “Every hire who interacts with customers has walked in their shoes,” she says. This credibility was key to building trust in an industry where relationships and reputation matter as much as results. That trust has only been further buoyed by their impact on the field: Trunk Tools answers critical spec questions in under 30 seconds, saves project managers 25 hours a week on admin, and avoids 100K in monthly rework cost.
4. Establishing an Advantage: Technical Moat and the Power of Brand
In construction, understanding drawings takes an enormous amount of effort — Trunk Tools spent 3 years building a proprietary vision stack and a construction-specific ontology to parse complex plans and job-site context. That combination of models, ontology, and processes around them is the core technical moat, reflective of lived experience, hard-won datasets, and domain expertise. A modular architecture helps the system flex to different jobsite realities without breaking.
But Sarah argues that brand matters too, especially in a “small world” industry like construction. Credibility in the field helps to compound reputation and further embed technically defensible products.
5. Scaling and Fundraising: From Vision to Proof
Sarah emphasized how proof points for fundraising evolve as you scale — Series A was about vision and early traction: proving the problem was real and the wedge worked. Series B raised the bar to proof at scale: revenue growth, expansion, usage, and a repeatable sales motion.
“The bar is undoubtedly higher,” says Sarah, “we had to show that what we’ve built actually works, can scale, and has staying power in the market. I also love that all of the investors who tried to get in the round did their due diligence with our customers way before they even spoke to us.” In vertical markets, happy customers become the strongest validation signal.
Takeaways for Founders
Credibility starts with time spent with the customers — it compounds when you ship against what you learn in the field
AI as a teammate beats AI as a replacement, especially in change-resistant sectors
Trust is a feature in relationship-driven markets, and your team is part of the product
Your brand should amplify your defensible technical spine once it’s field-proven
Treat customer love as your data room: retention, expansion, and referenceability are the proof points that close the gap from story to scale
What We’re Excited About at BBG
At BBGV, we’re excited to back underrepresented founders leveraging AI in legacy and overlooked industries, helping their customers automate workflows end to end. If you’re building in this space — or you are an investor exploring the impact of AI on industry-specific innovation — we’d love to connect. Reach out: claire@bbgv.com and susan@bbgv.com.
About BBGV:
BBG Ventures is a pre-seed and seed fund investing in underestimated founders building solutions for our polycultural future. Our founders are tackling the biggest arenas of the economy that require reinvention: health and wellbeing, work and education, financial security, energy resiliency and overlooked consumers. We look for founders who want to move the world forward, and whose unique combination of lived and learned experiences give them a competitive advantage.