Transite siding — cementitious shingles bound with chrysotile asbestos — was widely installed on residential and accessory structures from the 1930s through the late 1970s. While it's bonded into a hard cement matrix and not friable in its intact state, any cutting, drilling, sawing, or impact event releases respirable fibers from the broken edge.
The most common contamination event we get called for is a homeowner power-washing transite siding before a paint refresh — the high-pressure stream pulverizes the surface and aerosolizes fibers across the yard, the home interior, and the neighborhood. The second is partial repair after storm damage, where homeowners saw broken shingles to size without containment.
We assess whether removal is warranted, plan controlled wet-method work practices when it is, and double-bag everything for manifested disposal at a licensed facility. Encapsulation — paint over intact siding — is sometimes the right answer; we'll tell you honestly when it is.
Durham combines historic-district housing with mid-century ranch neighborhoods and a substantial older commercial inventory. All three of those building eras commonly contain asbestos materials in the places renovations want to touch.