Sarah Buchner

Founder & CEO Trunk Tools

Last Reviewed: September 19, 2026

Executive Summary

Sarah Buchner is unusual among construction technology founders in having actually built things. She started as a carpenter in Austria and worked up through superintendent and project manager roles on increasingly complex sites, including leading Building Information Modeling on what her conference biography calls the first as-built BIM project in Europe, on a site worth around €300 million. She took a master’s in civil engineering and then a doctorate applying AI to construction, and founded Trunk Tools in 2021 while completing a Stanford MBA. The company is now an AI layer over the documentation that construction projects generate — drawings, specifications, submittals, RFIs and change orders — built on the observation that general-purpose models cannot read construction drawings and legacy construction software cannot reason across documents. It has raised more than $70 million, is live on 1,000 US projects representing about $50 billion of construction volume, and counts Gilbane, Suffolk and Consigli among its customers.

Career Highlights

• Founded Trunk Tools in 2021 as a solo founder, developing the concept during her Stanford MBA through a research-driven ideation process aimed at construction’s labour shortage.
• Raised more than $70 million from Insight Partners, Redpoint, StepStone and Innovation Endeavors.
• Reached 1,000 live US projects covering roughly $50 billion of construction volume, with customers including Gilbane, Suffolk, Consigli, AMLI, Doka, STO, Baker and Charps.
• Pivoted the company from TrunkPerform, a worker productivity and compensation product, to TrunkText, a patent-pending text-message-based AI assistant for construction documentation, and then into a multi-agent platform running on the Cortex engine with tools for submittals, RFIs, reviews, registers, bids and change orders.
• Trained custom models on more than five years of real jobsite data and achieved SOC 2 Type II certification.
• Led BIM on what is described as the first as-built BIM project in Europe, on a roughly €300 million site, and earlier built a health and safety application for construction.
• Subject of a 2025 Stanford Graduate School of Business case study (case E880) by Kim Latypov and Garth Saloner, covering founder-market fit, solo founder dynamics and product strategy under technological disruption.
• Named an ENR California Top Young Professional and a speaker in ENR’s Groundbreaking Women in Construction programme.

Professional Journey

Buchner’s career began on site rather than in an office. She trained and worked as a carpenter in Austria, then moved through superintendent and project manager roles on progressively larger and more complex projects. That progression matters commercially as well as biographically: construction is a sector where software sold by people who have never worked a site is treated with justified suspicion, and her credibility with foremen and superintendents is a genuine asset the company markets directly.

Her move toward technology came from inside the work. She led Building Information Modeling on a large European project — described in her conference biography as the first as-built BIM implementation in Europe, on a site of roughly €300 million — and built a health and safety application for construction early on. She then took a master’s in civil engineering and a doctorate combining data science and civil engineering, focused specifically on applying AI to construction.

Trunk Tools was founded in 2021 while she was completing an MBA at Stanford, where she used a structured ideation framework to work from the industry’s labour shortage back to a product. The first product, TrunkPerform, attacked that problem directly by tying worker incentives and compensation to project outcomes. The Stanford case study of the company centres on what happened next: TrunkText, an AI tool letting construction professionals query large volumes of unstructured project documentation by text message, also found product-market fit, and Buchner had to choose between two viable products with limited resources, as a solo founder, while the underlying AI technology moved rapidly beneath her.

The resolution was to commit to the documentation intelligence direction. The company now describes itself as the AI intelligence layer for construction, built on Cortex, a core engine that reads project documents and identifies the connections between them, with a set of purpose-built tools layered on top — TrunkText, TrunkSubmittal, TrunkRegister, TrunkReview, TrunkRFI, TrunkBid, TrunkBrowse and TrunkChange. The models are trained on more than five years of real jobsite data rather than adapted from general-purpose systems, which is the company’s stated reason that generic AI cannot do this job.

Adoption has come from large general contractors — Gilbane, Suffolk and Consigli among them — and the company pairs the software with on-site training and change management, an acknowledgement that the binding constraint in construction technology is usually adoption rather than capability.

Education

Stanford Graduate School of Business

MBA

Institution not established

PhD, data science and civil engineering, on AI applications in construction

Institution not established

Master’s degree, civil engineering