House Has a Steel Frame: A Wolf Can't Blow It Down
STEEL VS. WOOD
Drilling screws into steel is a lot easier than banging nails into wood.
"I really enjoy it," says Ed Mander, a carpenter working on a new house where the studs in the wall are made of steel not lumber. "The materials stay perfectly straight. Steel doesn't absorb water and warp."
The house he's finishing is in Scarborough, one of the five cities which make up Metropolitan Toronto. It is unusual because the builder is using construction techniques usually reserved for commercial and industrial buildings.
"These steel members give you greater flexibility with the design," says Danny Tsang in the basement of the three-story house, his hands holding the 2 inch by 8 inch studs that sit under the floor. "The steel studs are stronger and they can span much farther than a normal piece of lumber."
Mr. Tsang is an immigrant from Hong Kong, a Canadian-trained engineer who built residential and commercial buildings until he started his company, Blockwood Construction, six years ago. He has built industrial buildings with steel, but this is his first steel house.
"Lumber is getting more and more expensive, and a lot of people worry about the environmental issue, cutting trees down. So it's about time we looked at different ways of constructing a house," says Tsang.
The steel industry is helping with the job. The Canadian Sheet Steel Building Institute is trying to promote the use of steel in residential construction. This is believed to be the first house in Toronto framed in steel and not wood.
The steel industry pushes the environmental issue, saying it takes the steel from six scrap cars to build this 2,200 square foot house. The wood for framing would take 40 to 50 logs 1 foot in diameter, they say.
The amount of energy needed to produce a ton of steel has dropped 40 percent since 1972 and continues to decrease, says the Sheet Steel Building Institute. "It is a high-quality alternative to traditional wood framing materials."
Not everyone agrees.
Angus Culley is an architect and builder of residential and commercial buildings in Vancouver, British Columbia.
"A big issue in northern climates is thermal bridging," says Mr. Culley. In plain English, steel easily conducts cold, wood does not. "The beauty of building with wood is its low thermal bridging. There is a lovely inherent efficiency of wood studs. But the cold can scoot right through steel. You have to add a lot of external insulation."
But Culley says using steel studs "makes a world of sense in southern climates."
The steel industry says a house built of its studs is every bit as well insulated as one built with wood.
A steel joist weighs one-third as much as a wood joist. And carpenter Ed Mander says it is easier to work with.
Contractor Tsang says that wood prices have gone so high steel can compete. Steel materials cost 2 to 3 percent more. A carpenter takes 10 percent more time at first, but about the same after getting used to working with steel. "Overall the cost is 5 percent more than using wood," says Tsang. "But I expect to save on after-sale problems. There will be no shrinking to cause cracks in the plaster, no squeaky floors, and no sticking doors that have to be repaired."
The biggest problem is tradition, architect Culley says. Carpenters are reluctant to lay down the hammer for the screw gun.