Construction Mastics & Gunning Mix

Mastics and gunning mix are building materials used to repair or fill industrial materials such as furnaces, tile or flooring. Asbestos was commonly added to these products as it is strong, durable and able to withstand high temperatures.

Construction Mastic and Gunning Mix

Mastic is a paste-like cement that is used as an adhesive, sealant and joint-filler. This product may be used in residential homes or commercial buildings in areas such as:

• Under floor tiles
• Ceiling tiles
• Acoustical tiles
• Roofing
• Walls
• Windows

The National Emission Standards for Hazardous Air Pollutants considers construction mastic to be a Category I non-friable asbestos-containing material. This classification indicates that mastic contains 1 percent or more asbestos and may emit asbestos fibers if disturbed.

Mastic may become friable, or able to become reduced to powder with little pressure, through the following actions:

• Grinding
• Sawing
• Drilling
• Cutting
• Abrading
• Renovating
• Demolition

Gunning mix is also a type of paste that is may be applied to metals, plastics, wood or masonry as a repair compound. This product is commonly used to fill in gaps or spaces in the surfaces of the following equipment:

• Steel furnace lining
• Hulls
• Storage tanks
• Sonar domes
• Pump casings

Gunning mix may also be used to smooth pitting, rough surfaces or irregularities that may occur in equipment lining.  Over time, asbestos-containing gunning mix may disintegrate or crumble. This may expose those who contact gunning mix or may be nearby the material to asbestos fibers.

Construction workers who install, remove, repair or perform other maintenance to structures may have been exposed to asbestos. Fibers that have been emitted from asbestos materials can remain airborne for several hours or days and can be breathed in or swallowed by those in contact with the material.

Removing Asbestos Mastic

Asbestos-containing construction mastic may be applied to a variety of household products such as floor tiles or roofing materials. Homeowners may remove mastic that is whole and intact. Mastic that has been applied to insulation board or lagging should be removed by a certified asbestos abatement contractor.

Homeowners should follow the following guidelines when removing asbestos-containing mastic:

• Remove all furniture or personal items from the room
• Cover nearby objects with sheeting to avoid contamination
• Wear proper safety equipment
• Scrape off mastic that has been softened though heating or applying a solvent material
• Avoid creating dust or scattering pieces of mastic
• Wipe down surfaces and clean the area with a vacuum
• Seal debris in polythene bag and dispose of the materials in an asbestos-approved garbage location

Many states require homeowners to use professional, trained contractors when removing asbestos products.

Construction Mastic, Gunning Mix and Mesothelioma

Asbestos fibers that have been inhaled or ingested may remain lodged in the body, as fibers can become caught in the thin membrane that surrounds internal organs such as the lungs, heart and abdomen.

Once in the body, the fibers cannot be expelled and can cause irritation and inflammation. The continued irritation of the membrane lining can cause life-threatening health conditions, which include lung cancer, asbestosis and mesothelioma.