Industrial roofing has evolved from the days of the granite and brick textile mills of yesteryear to the modern steel structures of today.

This is a brief overview covering the most common types of roofing in the northeastern United States. Numerous other types of roofing are also in use. Chaffee can determine your roof type and your best repair/replacement options.

TYPICAL INDUSTRIAL ROOF LATE 1800s
Roof:
Five-ply coal tar pitch with rag felts and gravel surface
Insulation: None
Deck:
Three-inch thick tongue-and-groove wood planks on wood beams
Slope:
Enough for good drainage
Roof mounted equipment:
Little or none
Comments:
Very rigid deck provides solid base for roof. No insulation allows heat to pass through roof, keeping it relatively warm and stabilizing temperature fluctuations.

Coal tar pitch "self heals" in summer. A good slope gets water off. Due to multiple stories, roof is one-third to one-fifth the size of total floor space. Typical roof could last 30 to 50 years.

TYPICAL INDUSTRIAL ROOF 1960s
Roof:
Three to four-ply asphalt with paper or fiberglass felts
Insulation:
One-inch fiberboard or Purlite (approx. "R" value = 2.8)
Deck:
Corrugated steel on bar joists
Slope:
Little or none
Roof-Mounted Equipment:
Fans, HVAC equipment, expansion joints, and roof drains
Comments:
Corrugated steel deck allows for deflection, especially under snow loads. Insulation provides base for roof but not much "R" value. Water often ponds on roof. Buildings are usually one story, so roof size is the same as floor space, which allows for lots of expansion and contraction. A typical roof life is 20 years.

TYPICAL INDUSTRIAL ROOF 1990s
Roof:
Single-ply membrane either ballasted, fully adhered, or mechanically fastened
Insulation:
2.7" polyisocyanurate insulation ("R" value = 20)
Deck:
Corrugated steel on bar joists
Slope:
Slight to none
Rooftop Equipment:
Fans, HVAC and anti-pollution equipment, satellite dishes, expansion joints, and roof drains
Comments:
Membrane can more easily accommodate deck deflection, and expansion and contraction typical of larger steel decked facilities. Also temperature fluctuations at roof level are more pronounced due to increased insulation. Most projects carry manufacturer's 10-year labor and material warranties.

TYPICAL INDUSTRIAL ROOF 2005
Insulation upgraded from 2.7” to 3.3” to meet increased “R” values, for energy efficiency. Typical Warranty now expand 15 to 20 years. Green roofs and photovoltaic are being consideration for more applications.