Laminate: to bond two or more layers of a material together to make a finished product.

 

Laminated Shingles: see Dimensional Shingles or Architectural Shingles.

 

Lap: that part of a roofing, waterproofing, or flashing component that overlaps or covers any portion of the same or another type of adjacent component.

 

Lap Cement: an asphalt-based roof cement formulated to adhere overlapping plies or asphalt roll roofing.

 

Lead: a soft workable metal used for miscellaneous flashings.

 

Leader Head: see Conductor Head.

 

Life Cycling Costing: a method of economic analysis that takes into account expected costs over the useful life of an asset.

 

Live Loads: temporary loads that the roof structure must be designed to support, as required by governing building codes. Live loads are generally moving and/or dynamic or environmental, (e.g., people, installation equipment, wind, snow, ice or rain, etc.).

 

Load Deflection: see Deflection.

 

Loose-laid Membranes: membranes that are not attached to the substrate except at the perimeter of the roof and at penetrations. Typically, loose-laid membranes are held in place with ballast, such as water-worn stone, gravel, pavers, etc.

 

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