CASE STUDY: 345 HARRISON, BOSTON

Photos: © Bill Horsman; courtesy of Bison Innovative Products

345 Harrison, Boston

Copley Wolff Design Group – Landscape Architects and CBT Architects designed a versatile rooftop space using a pedestal deck system with modular wood tiles for 345 Harrison Apartments located in the desirable South End neighborhood of Boston.

Apartment living has become more competitive in the nation’s top markets, and Boston is no exception. This neighborhood is home to vintage shops, jewelry stores, antique furniture markets, and urban eateries all within walking distance of this apartment building. The apartment’s amenities include a rooftop dog park done in synthetic turf, a pool with surrounding pool deck done in stone paver tiles, and lounge area with gas grills, seating, and a 12-person firepit with glass details. All these amenities express the building’s upscale character and are supported by an underlying pedestal system structure.

Smooth 2-foot x 2-foot ipê wood tiles were placed over an adjustable pedestal system to provide modularity. The pedestal system supports more than just the 2-foot x 2-foot ipê wood tiles—it also supports traditional joist and plank ipê decking, concrete pavers, and artificial turf for the dog park, thus expanding the variety of surface materials found on this rooftop space. This case study is an example of an outdoor space that benefits both people and the environment. It provides a rooftop garden that encourages social interaction, outdoor activity, and relaxation while reducing heat transmission into the environment.

Redwood: A Durable and Aesthetically Beautiful Material

The natural beauty, durability, strength, and warmth found in real redwood lumber and timbers are what make it an excellent wood for outdoor projects. Redwood has shear strength up to five times greater than plastic or composite decking. Redwood is a lightweight wood that is easy to work with, thus helping to lower overall construction costs.

Redwood lumber is available in a wide selection of grades, and it can be used for many common building applications, including decking, fencing, pergolas, building siding and trim, and many other landscape uses.

Redwood lumber and timbers may be used by architects and designers interested in designing to low- (or no) fossil-fuel, greenhouse-gas-emitting energy performance standards. The range of uses include commercial, industrial, and residential properties. Redwood is available in 1-inch and 2-inch dimensional lumber and in 4-inch, 6-inch, 8-inch, and larger timbers.

Timbers are the largest pieces of solid-sawn lumber produced by sawmills. Timbers are typically 5 inches thick and larger. Redwood is one of the lightest yet structurally strong softwoods found in North America, making it an ideal wood for a wide range of structural applications where large timbers are required. Structural applications for redwood timbers have been used for shade structures, gazebos, pergolas, arbors, and deck framing in outdoor design projects.

Redwood Grades

Redwood lumber and timbers are available in a wide variety of grades, including sapwood and heartwood grades. The term “grade” in lumber refers to the strength, durability, and appearance of the wood. Grades of redwood lumber are determined using criteria outlined by the Redwood Inspection Service (RIS). The grades provide guidance in determining the best use for the redwood based on its durability and appearance. Appearance is an important factor in selecting both color and the presence of knots. Durability is important in determining whether the lumber is appropriate for in-ground contact or can only be used aboveground.

Redwood is graded for its durability or resistance against insects and decay. These factors are actually easily distinguished by the color of the wood. The reddish-brown heartwood from the inner portion of the tree contains extractives that provide resistance to insects and decay. Thus, all heartwood grades of redwood will have the word “heart” in the grade name. Heartwood grades include Heart Clear, Heart B, Deck Heart, Construction Heart, and Merchantable Heart.

Garden grades of redwood contain more knots and natural characteristics than are allowed in higher, architectural grades. Garden grades of redwood include Deck Heart, Construction Heart, Deck Common, Construction Common, Merchantable Heart, and Merchantable. These are the grades that are more frequently used for decks, fences, and garden structures where knots or other visual characteristics have little to no effect.

For the finest uses, the architectural grades of heartwood are appropriate. Architectural grades include Heart Clear, Heart B, Clear, and B Grade, and may be available kiln dried (preshrunk and stress free) for fine exterior and interior uses. These are the choice grades for applications where attractiveness and tight joinery are desired as well as dimensional stability.

Sapwood is the cream-colored wood that develops in the outer growth layer of the tree, but it does not possess the same resistance to decay and insects that redwood heartwood does. However, redwood that contains sapwood can be used in construction aboveground where there is little danger of damage from insects or decay. Sapwood grades include Clear, B Grade, Deck Common, Construction Common, and Merchantable. These sapwood grades can be used for decking that does not contact the ground, garden shelters, and other aboveground outdoor applications, such as benches and seating.

Appearance is the other major factor in the grading of redwood. The rich, warm texture and grain pattern of redwood hold true even with age. Freedom from knots, or clearness, is the determinant for the highest grades. Other grades are categorized by the number, size, and nature of knots as well as the presence of other characteristics such as stains or manufacturing defects that may occur during the milling process.

Redwood decking also features Class B flame spread and is approved for use in California’s Wildland Urban Interface (WUI) fire-hazard severity zones without restriction. In order to provide a Class A flame-spread rated product, redwood lumber and timbers can be treated with an exterior fire retardant. The result is a Class A exterior decking product. The product is covered by a limited lifetime warranty. In addition to decking, accessory items such as joists, railings, and other specialty items are available.

The Class A flame-spread rating means that the treated redwood product can be used under even the most stringent Wildland-Urban Interface (WUI) building codes throughout the United States, including the International Code Council’s International Wildland-Urban Interface Code (IWUIC). The IWUIC code requires decks to be constructed of approved fire-retardant treated wood specified for exterior use. Under such guidelines, only a Class A flame-spread rated exterior wood product would qualify for usage.

CASE STUDY: OUTDOOR KITCHEN, PRIVATE RESIDENCE, EUREKA, CALIFORNIA

Photo courtesy of Humboldt Sawmill Company

Redwood was used for the construction of this large pergola that provides outdoor socializing 12 months of the year.

Outdoor kitchens extend living spaces, making home entertaining easier, especially with large gatherings. A Eureka, California couple knew that an outdoor kitchen would be a special environment for them to use 12 months of the year. The design began as an outdoor fireplace, but quickly expanded into an outdoor kitchen, living, and entertainment space. The entire outdoor living space was then capped by a custom-built redwood pergola that provides the perfect outdoor space. The homeowners are frequently asked to host events due to the size of the yard and the patio and this pergola structure provides a wonderful enhancement to those large events.

The redwood pergola was built in two sections with the section over the kitchen and living area being covered by a shingled roof. The section over the dining area has a clear, corrugated plastic roof that allows natural light in. As Eureka receives a lot of rain and fog, this roof covering allows the homeowners to use the space as often as possible.

Ideas For Creating Interesting and Well-Designed Outdoor Environments

Architects and designers can create decks and pergolas using redwood lumber and timbers to expand residential and commercial outdoor environments. Pergolas provide shade and when combined with plantings can reduce heat island effects. Pergolas also help homeowners and businesses to take their social gatherings outside.

Photo courtesy of Humboldt Sawmill Company

Redwood timbers were used to create this pergola located in Farmington, New Mexico.