Plain-language definitions of the terms you will hear from roofing contractors, inspectors and manufacturers. If a word comes up that is not here, call 832-663-5225 and ask.
- Built-up roofing (BUR)
- A multi-ply roof of bitumen and reinforcing felts, often finished with gravel.
- Core sample
- A small cut through the roof layers to see their makeup and check for moisture. It is patched afterward.
- Deck
- The structural surface the roof sits on, usually steel, concrete or wood.
- EPDM
- A black synthetic rubber single-ply membrane.
- Flashing
- Material that seals the roof where it meets walls, curbs, edges and penetrations. A common leak point.
- Fluid-applied system
- A roof membrane applied as a liquid, often with embedded reinforcing fabric, that cures into a continuous layer.
- Infrared survey
- A thermal-camera scan that can reveal wet insulation by how it holds and releases heat.
- Insulation
- The layer between the deck and membrane that slows heat flow. Wet insulation loses much of its value.
- Membrane
- The waterproof layer of the roof system.
- Modified bitumen
- An asphalt-based roof system, applied in layers, with polymer modifiers for flexibility.
- Moisture scan
- Any method of mapping trapped moisture in a roof, such as infrared, impedance or nuclear surveys.
- NDL warranty
- No Dollar Limit warranty: a manufacturer warranty that covers qualifying repairs without a dollar cap. Terms vary by product.
- Parapet
- The low wall that extends above the roof edge.
- Penetration
- Anything that passes through the roof, such as pipes, vents, HVAC supports or fasteners.
- Ponding water
- Water that remains on the roof 48 hours or more after rain, usually a drainage problem.
- Port-to-port
- Service time measured from when the crew leaves dispatch until it returns.
- PVC
- A single-ply membrane with heat-welded seams, known for chemical and grease resistance.
- Re-cover
- Installing a new roof over the existing one without tearing it off, where code and condition allow.
- Restoration
- Repairing and renewing an existing roof in place with a new restoration system, when its condition allows.
- Scupper
- An opening in a parapet or edge that lets water drain off the roof.
- Single-ply
- Roof membranes installed as one layer of sheet material, such as TPO, PVC or EPDM.
- Tear-off
- Removing the existing roof, typically down to the deck, before installing a new one.
- TPO
- A white or light-colored single-ply membrane with heat-welded seams, common on low-slope roofs.
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