151-157 Allston Street
In July 2014, fire engulfed a six family building at 151-157 Allston Street in Cambridge. Firefighters put out the blaze, fortunately no one was injured, but all six families lost everything and their apartments were heavily damaged.Redeveloping 151-157 Allston Street became a top priority for our organization as we anticipated creating a healthier, more efficient model of housing and returning all six families to their homes. On September 1st, 2016, the project was completed with an extensive set of green features and a pending LEED for Homes Platinum certification by the US Green Building Council.
151–157 Allston Street’s building envelope is tightly sealed and insulated to minimize heat loss. The Home Energy Rating System (HERS) Index is the industry standard by which a home's energy efficiency is measured. 151–157 Allston Street will be receiving a HERS rating in 2016. The lower the number, the more energy efficient the home. The U.S. Department of Energy has determined that a typical resale home scores 130 on the HERS Index while a standard new home is awarded a rating of 100.
The walls at 151–157 Allston Street are insulated with 5½ inches of cellulose insulation on the third floor and 4 inches on the first floor with 1½ inches of additional mineral wool. Cellulose insulation typically contains 75–80% post-consumer recycled newspaper. Its thermal performance is similar to high-density fiberglass batts, but because it packs more tightly it is more effective at controlling air leakage. 151–157 Allston Street also has one inch of rigid insulation on the exterior, bringing the walls to an R-26.5 rating (the third floor is R-26). The roof is insulated to an R-50 rating. This means lower heating costs and a quieter, more comfortable home.
A smart vapor retarder and air barrier
A smart vapor retarder and air barrier (Intello) has been installed to minimize drafts and air infiltration. It lets wall cavities dry out, to help prevent mold. In summer, when humidity is high, it increases permeability so that moisture can escape, and air tightness is maintained. The blower door test for 151–157 Allston Street has not yet been scored.
Windows are double pane, insulated, argon-filled glazing with a low-E coating. The high-performance glazing helps control heat gain in the summer and heat loss in the winter.
151–157 Allston Street has a solar domestic hot water system that will preheat water to be used in the apartments. This will save approximately 800 therms of natural gas per year and will allow almost no natural gas usage for the building during the summer months.
A 9.81 KW solar electric system with 30 photovoltaic panels provides electricity to offset the lighting needs for the hallways, stairwells, outdoor lighting and pumps.
SITE: Crosswinds, the contractor, incorporated a construction waste management and recycling program to reduce the amount of construction waste that was sent to the landfill. Over 70% of demolition waste and 75% of all construction waste was recycled, including wood, concrete, gypsum, and cardboard.
The building was rehabbed using as much of existing materials as was possible after portions damaged by the fire were removed. Reusing an old building almost always has less of an impact on the environment than tearing it down, trashing the debris, clearing the site, crafting new materials and putting up a replacement from scratch.
A number of materials used at Allston Street were chosen for their recycled content. Recycled materials were also added to selected products. For example, flyash was added as an aggregate to strengthen the concrete mixes used on site. Flyash is a by-product of the coal industry, and is otherwise discarded after the manufacturing process.
Landscaping features drought-tolerant and low-maintenance plants with no invasive species.
151–157 Allston Street is a smoke-free building. Anyone who wants to smoke needs to exit the building and go at least 25 feet from all doors and windows.
Kitchens and baths have been outfitted with low-flow plumbing fixtures to reduce water use. Low-flow fixtures include shower heads, sink and lavatory faucets, and 1.28 gallon per flush toilets.
A storm water retention tank is used at the site to retard the flow of storm water into the City stormwater system. This can help prevent flooding of the street and basement during extreme storm events.
The building is heated with an energy efficient central boiler with digital controls. The boilers have an efficiency rating of 95%. The boiler is mounted on the wall to protect it in case of potential flooding.
Energy-efficient lighting, appliances, and controls are installed throughout the building. Many common area lights are controlled by occupancy sensors, daylight sensors, and timers in order to reduce electricity use. Energy Star appliances and LED lights have been installed in units to make sure that residents’ electricity bills are low and affordable.
INDOOR AIR QUALITY
Low-VOC paints and sealants were used throughout the building. All paints and sealants at Allston were selected for their low emissions of VOCs, contributing to improved indoor air quality.
Flooring materials were selected for their durability and health benefits. Prefinished hard wood floors are installed in all residential units. Wood is a durable, sustainable material that avoids emissions and dust and improves the air quality in the units and can lead to lower asthma and other health problems.
Each apartment gets ventilation through the continuous exhausting of contaminated air from the bathrooms with a very quiet, very energy efficient fan. The fan boosts its flow rate to more quickly eliminate odors and moisture when the room is occupied.