Old Canaan Building Materials

Cast iron is the material of traditional exterior railings, drain grates, cellar window guards, and hardware on New England buildings from the Federal period through the Victorian era. It is heavy, brittle, and does not bend — which is why it makes excellent compression members and poor tension members, why it is correct for posts and balusters and wrong for spans that carry bending load.

Dark grey to black, with a texture that ranges from smooth at machined surfaces to slightly porous at cast surfaces. It does not have the brightness of steel or the warmth of bronze. It is the color of a winter sky and the weight of something permanent. A cast iron railing does not flex when you push it. It is absolutely rigid and it communicates that rigidity in a way that hollow steel tube does not.

Cast iron is an iron-carbon alloy with a carbon content of 2 to 4 percent, making it hard and brittle compared to wrought iron and steel. It is formed by pouring molten metal into sand molds, which allows the production of complex shapes — the scrollwork, anthemion panels, and decorative balusters of Victorian-era ironwork. Architectural cast iron is available as reproduction from Robinson Iron in Alabama, which has been producing architectural cast iron for historic restoration projects for decades.

Cast iron does not corrode as rapidly as steel but it does rust. It requires paint — traditionally black or dark green — applied over a rust-inhibiting primer. Cast iron is brittle and will crack or fracture under impact loads that wrought iron or steel would simply bend under. Repairs require welding by a skilled metal fabricator familiar with cast iron's specific welding challenges.

Cast iron is correct for railings, newel posts, fence panels, and cellar grates on Federal, Greek Revival, Italianate, and Victorian buildings in New England where cast iron is historically documented. Hollow-section steel tube painted to resemble cast iron is not correct — the profile, the weight, and the casting surface are all wrong.

Through architectural metalwork suppliers and foundries specializing in historic reproduction. Robinson Iron (Alexander City, Alabama) is the primary domestic source for reproduction architectural cast iron. For salvage original cast iron, architectural salvage dealers in New England occasionally have period railings and fence panels.