Lyman Estate Greenhouses project improves heating, accessibility

Oct 4, 2017

Lyman Estate Greenhouse, Grape House (c. 1804)

Lyman Estate Greenhouses, Grape House (c. 1804)

A comprehensive preservation project is underway at the Lyman Estate Greenhouses in Waltham, Massachusetts. Historic New England is working to upgrade existing mechanical systems, perform building repairs, and make this unique historic space – among the oldest surviving greenhouses in the United States – more accessible to all visitors.

The Lyman Estate Greenhouse complex is composed of two separate principle historic structures. The later structure encompasses a series of four connected wood-and-steel-framed greenhouses, each built at a different time. The western and oldest section (c. 1804) serves as a grapery; the easternmost section (c. 1820) houses a historic collection of Camellias; the center section (c. 1840) originally housed cultivated roses and now provides space for orchid production and maintenance; and the section that extends to the north, now referred to as the Sales House, dates to c. 1930. It originally provided the Lyman family with a variety of cut flowers and now acts as a home base for the retail operation.

The project began in spring 2017 with window conservation, focusing on the glass roof and side vents of two of the greenhouses. Our contractor removed and re-glazed the window sash that vent these spaces. To ensure visitor safety, we replaced the roof vent glass with laminated glass, which had minimal aesthetic impact. We also restored the wall caps that create the sill of the side vents as well as the operable hardware for these vents. This work was partially funded by a grant from the Massachusetts Historical Commission.

Before and after photo of conservation work to windows in the Sales House

During work and after photo of conservation to windows in the Sales House

In July, we moved on to the interior of the greenhouses. The plant benches (which, we discovered, have been repaired and rebuilt multiple times over the last eighty years) were dismantled. This involved properly disposing of all corrugated Transite surfaces. While a great insulator, Transite proved problematic as a plant bench surface, because it prevented heat from efficiently reaching the plants above. A new bench system with an expanded metal mesh surface will allow heat to circulate to the plants’ roots more effectively.

In fact, we are working to provide more efficient and consistent heat for plants throughout the greenhouses by upgrading the heating system. The previous system, which used hot water pumped through cast-iron pipes, is largely retained in place for historical accuracy. There was only a loss of approximately 12% of the historic cast-iron pipes to make way for the new fin tubes. The new system uses fin tubes (tubes with fins around their outside surfaces that allow for the transfer of heat from a hot fluid to a colder fluid through the tubes’ walls) as a heat delivery method. These are mounted next to or under the existing cast-iron pipe, and are minimally visually intrusive in the majority of the spaces.

On the exterior, masonry repointing took place in order to patch areas of mortar loss and areas that required minor rebuilding. Perhaps the most significant area that required rebuilding was on the north side of the c. 1840 greenhouse. A historic chimney, originally used to vent heat from fireboxes below, required extensive rebuilding, and is now less vulnerable to external factors that cause deterioration.

New sloped walkway into the westernmost Grape House

New sloped walkway into the Grape House

We are also making both the interiors and exteriors more accessible. Two sloped walkways – one at the western entrance to the Grape House and one between the c. 1840 House and the c. 1820 house – have been added. The Grape House walkway allows visitors of all mobile abilities to experience the first of the three Grape Houses. The walkway between the c. 1840 and c. 1820 houses allows guests to progress through the Camellia House and enter into the c. 1840 house, which will become the sales area. This allows guests of all mobile capabilities to see more of the greenhouses than ever before.

The pathway that runs along the south face of the greenhouses has also been widened and the surface replaced with a stone dust, while still following the existing (and historic) curvatures of the path. The eastern entrance to the Camellia House has become the primary entrance for guests, who can then progress through the Camellia House up the sloped walkway into the c. 1840 house.

On the north side of the greenhouses, the existing gravel pathway will be replaced with a more even surface of chip seal, and the path will be extended north along the west side of the c. 1930 house to the Hoop House. This will also enable all Historic New England visitors to experience more of the Lyman Estate.

The project is expected to be 95% complete in time for the Fall Orchid Sale, October 20 to 22. Stop by and see the progress, and pick up some beautiful orchids for your home.

You can help save and share historic sites like the Lyman Estate Greenhouses by making a gift to the Preservation Maintenance Fund