Boston Triple-Decker Inspection Guide

Published January 18, 2026 by Editorial Team

Boston, MA

Massachusetts landscape

Key Takeaways

  • Triple-deckers require inspection access to all three units
  • Shared systems (heating, electrical) create different considerations than single-family
  • Rental history and tenant improvements affect property condition
  • Lead paint compliance is critical for rental properties in Massachusetts

Boston's triple-deckers are a regional housing type found throughout Dorchester, Jamaica Plain, Somerville, and surrounding neighborhoods. These three-story, three-unit buildings were built primarily between 1870 and 1930 to house the city's working families.

Inspecting a triple-decker differs from inspecting a single-family home. Multiple units mean multiple kitchens, bathrooms, and living spaces to evaluate, plus shared systems that serve the entire building.

Access and Logistics

A thorough triple-decker inspection requires access to all three units. This can be complicated when units have tenants:

  • Coordinate with seller to arrange tenant access during inspection window
  • Expect the inspection to take longer than a single-family (3-5 hours typical)
  • Some areas may be inaccessible due to tenant belongings or restrictions
  • Exterior and common areas should be fully accessible

If access to certain units is denied, that should be noted in the inspection report. Consider what risks you're accepting by not seeing every space.

Shared Systems

Heating

Triple-deckers typically have either a single boiler serving all units or individual heating systems per unit. Shared boilers require understanding who pays for fuel and how heat is distributed. Individual systems (common in condo conversions) are easier to evaluate.

Electrical

Older triple-deckers may have electrical setups that don't clearly separate by unit. Each unit should have its own panel and meter. Shared or unclear electrical situations create both billing and safety complications.

Plumbing

Main stacks and sewer lines serve all three units. A problem on the third floor affects everyone below. The inspector should trace plumbing routing and note any visible issues in common drain lines.

Common Triple-Decker Findings

  • Porch condition: Triple-deckers are famous for their three-story porches. These are often in various states of repair and can be expensive to rebuild.
  • Roof and siding: Large surface areas mean higher replacement costs than single-family homes.
  • Foundation: Rubble foundations supporting three stories of living space. Settlement and moisture issues are common.
  • Code compliance variations: Units may have been updated at different times, creating inconsistent conditions.
  • Tenant modifications: Unauthorized changes by tenants over the years.

Lead Paint Compliance

Massachusetts has strict lead paint laws for rental properties. If the triple-decker will be rented (even partially), lead compliance matters:

  • Properties built before 1978 are presumed to contain lead paint
  • Landlords must provide lead-safe housing for units with children under 6
  • De-leading or containment costs can be significant
  • Inspection reports should note condition of painted surfaces but won't test for lead specifically

Budget for lead paint assessment and potential remediation if buying a triple-decker as an investment.

Owner-Occupant vs Investor

Your inspection priorities may differ based on how you'll use the property:

  • Owner-occupant: Focus on the unit you'll live in plus shared systems. Rental income helps offset ownership costs but unit condition affects your daily life.
  • Investor: All three units matter equally. Focus on systems, roof, and structural elements that affect the entire building. Cosmetic issues in individual units are less critical.