Sarah Buchner built Trunk Tools from a carpenter’s view of construction data
Former carpenter Sarah Buchner turned construction’s fragmented paperwork into Trunk Tools, which raised a $40 million Series B in 2025.
By Ingrid Halvorsen · Venture Capital Reporter
· 3 min read
Sarah Buchner Trunk Tools is the story of a former carpenter building software for the document-heavy work she once managed herself. The New York company announced a $40 million Series B in July 2025, bringing its stated total funding to $70 million, as it seeks to sell AI tools to contractors working across drawings, schedules, specifications and other project records.
Insight Partners led the round, with Redpoint Ventures, Innovation Endeavors, Stepstone, Liberty Mutual Strategic Ventures and Prudence participating, according to Trunk Tools’ announcement. The company did not disclose revenue or a current valuation in that announcement. Crunchbase News reported that the 2025 financing valued the company at $325 million, citing Buchner.
Buchner grew up in a low-income household in a small Austrian village, where her father worked as a carpenter. She began carpentry work at 12, according to Buchner’s account to TechCrunch, later syndicated by Yahoo Finance. Her construction career moved through superintendent, project manager and group-leader roles, and she eventually managed large European projects as a general contractor, Crunchbase News reported.
How did Sarah Buchner found Trunk Tools?
A fatality at a site she was running changed Buchner’s view of the work, she told Crunchbase News. She then built a separate health-and-safety app for construction workers, before Trunk Tools existed. That effort brought her into software and led to doctoral research focused on construction data science and early AI.
Her research identified the company’s eventual target: information scattered across systems and embedded in unstructured files. Buchner has estimated that a typical site can produce 3 million to 4 million pages of documentation. That scale is a workflow problem for contractors, subcontractors and project owners, not merely a search problem.
Buchner moved to California for Stanford Graduate School of Business in 2019, founded Trunk Tools in 2021 while enrolled there, and graduated in 2022, according to Crunchbase News. She said the startup did not find its first meaningful product and market until 2023. Buchner is a solo founder; she told Crunchbase News that she hired experienced AI engineers early rather than adding a technical co-founder.
What does Trunk Tools do for construction teams?
Trunk Tools says its platform organizes project material including drawings, specifications, requests for information, schedules and submittals. Users can ask questions in natural language, while its agents are designed to review documents, identify inconsistencies and connect information across workflows. The company also says the software can connect documentation to project schedules to flag potential problems.
Those are company product claims, and the evidence pack does not independently assess the quality of the system’s answers or its effect on project outcomes. The narrower case for the product is that Buchner’s experience supplied direct knowledge of the documents and handoffs the company now targets.
The Series B followed Trunk Tools’ $20 million Series A, led by Redpoint in August 2024, which brought the company’s funding then to $30 million. Trunk Tools said the newer capital would go toward engineering, product and go-to-market hiring, field enablement and expanded platform capabilities.
This story draws on original reporting from Crunchbase News.
