Home Improvement / Gardening : Advantages of Using Steel in Framing Home

QUESTION: Because of the price of lumber, I am considering using steel studs for framing my new home. Can I get good insulation value with steel studs? Is more insulation required?

ANSWER: Steel currently enjoys a 20% to 25% price advantage over lumber. As a result, many builders are interested in using steel framing in residential construction. Your concern about maintaining insulation value when you use steel studs, however, is justified. To maintain the high standards required in today’s energy efficient homes, you must pay special attention to insulation details when you use steel studs.

Steel is a poor insulator. When it replaces wood framing members in the exterior shell of a building, it provides a path for heat loss that bypasses the insulation in the walls and other building cavities. This effect is known as thermal bridging. Wood studs (a better insulator than steel) produce some thermal bridging, but the effect is much more pronounced with steel.

To compensate for the lower effective level of insulation with steel studs, you must add insulation to obtain the same R-value. This can be done by building a thicker wall providing room for more insulation or by attaching insulated sheathing to either the interior or exterior surface of the exterior walls. Insulated sheathing provides a “thermal break” by interrupting the flow of heat through the thermal bridge of the stud. In either case, the current savings in material costs achieved in switching from wood to steel studs may be offset by the additional cost of insulation required to maintain the same R-value.

Due to the problems in maintaining insulation levels, some builders have found it’s most effective to stay with wood framing for the exterior shell of the building and use steel studs only for interior partitions where thermal bridging is not an issue.

Often builders used to wood framing will replace wood with steel on a stick-for-stick basis. Better economy of labor and materials is possible if the house is pre-engineered for steel construction.

Pros and Cons of Steel Framing

Pros

--Steel has a higher strength-to-weight ratio than wood and can span greater distances.

--Steel is dimensionally stable and doesn’t have the grading inconsistencies of lumber.

--Steel doesn’t burn.

--Steel isn’t attacked by insects.

--Using steel reduces the need to harvest lumber.

--66% of U.S. steel comes from recycled material (cars, etc.).

Cons

--Steel framing is less forgiving than wood; foundations and framing must be level, plumb and square.

--Steel rusts; it must be treated or galvanized.

--Builders must learn new skills and acquire new tools.

--Steel production is energy intensive and can cause air and water pollution. The National Academy of Science estimates it takes nine times more energy to produce a steel stud than a wood stud.