TechPractices: Northern Enterprise Homes, Hartford, CT

PATH's Technologies in Practice are large scale housing projects throughout the U.S. where innovative technologies are being installed and used. Information is presented from the viewpoint of builders and remodelers who can use these examples as models for projects of their own.

Summary

Northern Enterprise Home Manufacturing, a new company located in Hartford Connecticut, is a pioneer in constructing homes with pre-cast foundations walls. They are building five in-fill duplexes in the Lawrence/Grand Street project in Hartford using pre-cast concrete foundation walls.

Krish Naraine, general manager of Northern Enterprise, built Energy Crafted Homes for three years prior to moving to Northern Enterprise. The Energy Crafted Homes program promotes increased energy efficiency in new construction and is sponsored by the local utility, Northeast utilities.

Mr. Naraine learned about pre-cast foundations in 1995 and contacted Superior Walls, a manufacturer of pre-cast concrete foundation walls, to obtain more information. After investigating the product, he became convinced that his own company could use it. The quality of the product and the overall installation cost of the system impressed Krish. Another important advantage of the system is that it allows construction to continue throughout the winter, since the concrete panels are cured at the factory. A Superior Wall foundation takes approximately five hours to erect and the building is immediately ready for its superstructure.

Details

The pre-cast foundation system consists of concrete wall panels joined to concrete ribs that serve as wall studs for reinforcement. Panels are produced according to the builder's specific foundation design that includes openings for doors and windows. The manufacturer uses polyurethane caulk to bond panels at joints and to prevent water from entering a basement. The interior wall cavity between the concrete studs contains one-inch thick extruded polystyrene insulation. Wall studs also have 3/4-inch thick wood furring strips on their interior face to allow for the installation of additional insulation and interior-finishing material such as drywall after the foundation is in place and weather-tight. Wall studs contain one-inch diameter holes to permit the installation of electrical wiring or water pipes.

Northern Enterprise incorporates multiple energy efficient features in their homes in addition to the foundation. They use double-glazed heat mirror windows, a drainwater heat recovery system, and a geothermal heat pump system. Exterior walls have R-19 insulation, and fluorescent lighting further reduces energy consumption. A mechanical ventilation system assures high quality indoor air.

Installation/Construction

Foundations are excavated and the footings lined with six inches of crushed stone to provide drainage and to support the walls. Pre-cast foundation walls are delivered on site by a truck and erected the same day using a crane.

A network of franchised manufacturers sells and installs the Superior Wall system. The extensive experience of installers minimizes the installation problems.

Benefits/Costs

In the Lawrence/Grand Street project, the cost of the pre-cast foundation is about equal to poured-in-place concrete foundation. The total installed cost for a 50 x 28-foot foundation is $7,800, including crushed stone for the footing and installation of the walls. The builder is only responsible for excavating the foundation. The major benefit for Northern Enterprise is an estimated time savings of two weeks in the construction schedule.

Code/Regulatory

The Superior Walls system is listed under BOCA Evaluation Report 89-53. The company provides an Inspection Procedure Support Data Booklet for use by the building officials to check the field installation. A professional engineer certifies the installation according to procedures outlined in the booklet but system installations still requires a local engineer stamp if this type of foundation has never been used in Hartford. A Superior Wall's representative also met with the building official to address any concerns with the product. The additional drawings increased engineering costs by $280.

Feedback

Krish reports "I like the pre-cast foundation system for its speed of installation and resistance to water penetrating the basement. The system also easily accommodates utility installation and interior finish with the holes and furring strips installed on the concrete studs."

Contact(s)

Do you have a specific question? Try the contacts listed below:

Superior Walls
937 East Earl Rd.
New Holland, PA 17557
800-452-9255
www.superiorwalls.com/

Northern Enterprise Home Manufacturing
780 A Windsor Street
Hartford, CT 06120
860-249-6117