Rocky Hill Co-Housing

The Rocky Hill Cohousing comprises 28 dwellings and a community building, situated on a 7.5 acre site in Florence, MA. It is one of over 150 cohousing communities built across the U.S. during the past two decades.

Cohousing promotes community vitality and mutual support between households using a shared common house and other community spaces as the driving mechanism. The common house includes dining space, guest rooms, childcare spaces, and craft and hobby facilities. Since it is created at the expense of dwelling units size, the building functions as part of everyone’s house. The need for convenient access to shared spaces, and the premium on preserving greenspace drives a clustered proximity of dwelling units in a human scale neighborhood arrangement.

Project Details

  • A basic formal rhythm across houses was achieved by offering residents a controlled pallet of of options for their dwelling unit.
  • The basic unit is essentially a 2-story square with a steep pitched roof that allowed for expansion downward to the basement to create a supplementary space and upward into the attic to create additional bedroom accommodations or a studio.
  • A second volume addition to the first floor is the primary mechanism for increasing the capacity of a Rocky Hill home. It allows for future expansion as family incomes and needs expand and supports fully accessible living. The direct connection to the exterior supports its use as a home office or an in-law apartment.
  • Rocky Hill houses also have the option of a small window-bay alcove module that can be added to the first floor kitchen-dining-living space to nest an activity such as a dining table or sitting area.
  • The introduction of a horizontal trim band at the window/door head level affords color separation at minimal cost. The community’s confidence in the saturated color hues has paid off. Color is cheap, but dramatic.
  • The arrangement of tightly clustered homes on the site allowed us to leave 2/3 of the parcel as undeveloped greenspace. This open space within the community is commonly held and the existing tree cover was retained.
  • It is a peculiar condition of co-housing development that the early committed participants have the tighter budgetary constraints, but the presence the aspiring homeowners as key development partners creates a force that drives toward customization, and price escalation. This can lead to those whose early and spirited effort created the project being left stranded as the cost of participation rises beyond their reach. Containing the force of customized cost escalation was a special constraint based on a group commitment to get everyone to the mountaintop.
  • At the time of Project Completion in 2007, the cost of construction was $120/s.f.
  • Reduced paving through the dwelling area and perimeter parking means a smaller-than-usual percentage of the developed property is impervious to rain water / storm run-off. That which remains is managed by bio-swales planted with phyto-remediating plant species.
  • Wall cavities were carefully detailed and filled with dense-pak cellulose insulation. The result was an average air-tightness reading of 1.8 ACH @cfm50, as shown through blower-door testing.
  • Roofs were oriented and sloped for solar collection (unless the owners asked for the alternate rotation). At the time of project completion, one resident had installed a 2KW photovoltaic system, and other dwellings had been prepared for future systems by the installation of conduit and piping through which to run the connections for both PV and solar thermal arrays.
  • Elimination of thermal bridges in the building enclosure create a more efficient envelope and prevent cold surfaces that could result in condensation and subsequent mold growth.


Pioneer Valley Planning Smart Growth – 2007 Award of Excellence

Western Mass AIA 2008 – Honor Award for Design Excellence

Boston Society of Landscape Architects – 2009 Merit Award

Project Team



Landscape Architects / Civil Engineering

Structural Engineering


C&H Architects, Amherst MA

Kohl Construction, Hadley MA

Berkshire Design Group, Northampton MA

Ryan Hellwig, P.E., Northampton MA

Scott Barrow