Construction Financial Assistant at One Source Construction LLC – Southborough, Massachusetts

📍 Southborough, MA | 🕒 Full-Time | Monday–Friday (In-Office)

One Source Construction LLC is a Massachusetts-based general contractor specializing in public and commercial projects. We operate in a fast-paced, compliance-driven environment where accuracy, documentation, and accountability are critical.

We are building a highly structured, process-driven accounting operation to support our continued growth. This role is critical to maintaining financial accuracy, supporting project profitability, and ensuring compliance across all projects.

We are seeking a detail-oriented and process-driven Financial Assistant to support our construction accounting operations.

This role is responsible for accounts payable, accounts receivable, job cost tracking, billing support, and maintaining audit-ready financial records.

This role is ideal for someone who takes ownership of processes, maintains high standards, and wants to play a key role in a growing construction company.

You will work closely with project managers and leadership, directly impacting billing accuracy, job costing, and financial visibility across projects.

• Prepare and submit AIA/progress billings
• Coordinate billing with Project Managers and field teams
• Process construction AP and AR transactions
• Perform job cost coding and tracking
• Reconcile company credit cards and track receipts
• Maintain accurate records in QuickBooks Desktop (Contractor Edition)
• Track subcontractor compliance (COIs, documentation)
• Maintain organized, audit-ready job and accounting files
• Follow defined SOPs and maintain logs for financial tracking

• Work must be completed accurately, consistently, and on time
• Filing, documentation, and reconciliation are part of “completion”
• Strong organizational discipline is required
• Ability to follow structured processes and checklists
• Comfortable working in a deadline-driven, detail-heavy environment

• 3+ years of bookkeeping/accounting experience in construction
• Experience with:
• • AIA / progress billing
  • Construction AP/AR
  • Job cost accounting
• Proficiency in:
• • QuickBooks Desktop (Contractor Edition)
  • Microsoft Excel, Outlook, Word
  • Adobe Acrobat
• Strong attention to detail and organizational discipline
• Ability to work full-time in-office

• Public/municipal construction experience
• Procore experience
• Notary Public (or willing to obtain)

• $60,000 – $80,000 (based on experience)
• Performance-based bonus
• Health, Dental, Vision
• 401(k) with company match
• PTO and paid holidays