Asbestos cement is a composite material composing of Portland Cement and asbestos fibers. Asbestos cement became very popular before being banned in the 1970’s. You will likely come across this material as you travel though “well established” (older) neighborhoods. Homeowners can benefit from knowing a little more about known health risks as they pertain to Asbestos siding as well as some common problems with the material.
Asbestos cement came into use as a siding material in 1907 when an Australian engineer came up with a method to form the material into sheets allowing it to be used as an exterior cladding and roofing material. In the 1920’s the National Fire Underwriters recommended that it replace wood siding due to its fire resistance characteristics. This boosted sales as by the 1940’s hundreds of thousands of homes were constructed with Asbestos Cement.
In the late 60’s however, reports began to surface noting the health hazards with asbestos and as reports increased the public became concerned. In 1973 the EPA banned the use of Asbestos in building materials for use a fire resistance or insulating material.
Asbestos fibers are a proven health hazard if inhaled. Asbestos dust is a known cause of a type of lung cancer called asbestosis. Mesothelioma, another deadly form of cancer that attacks internal organs, can also be caused by exposure to asbestos. However, asbestos cement siding that has been properly installed and is not in a state of decay presents no health risks as long as it remains undisturbed. This is because the cement binds the asbestos fibers and prevents their release into the air, under normal use and maintenance.
The EPA deems asbestos to be hazardous when it is in a friable state, meaning that it can be crumbled, crushed or pulverized by hand pressure. Damaged asbestos in a powdery form can allow its particles to become airborne and inhaled, causing potential health problems. Asbestos cement products that are not in a friable state are not considered hazardous. The only potential danger is when the cement is disturbed in a way that causes the asbestos fibers to become airborne.
Advantages of Asbestos Cement
- Highly fire resistant and will not melt or burn like other materials
- Resists termite damage
- Will not rot
- Easier to paint than wood
- Easy to maintain and clean
Disadvantages of Asbestos Cement
- Very Brittle, cement siding can be easily chipped or broken
- A pressure washer can easily break asbestos cement
- This product cannot be refurbished like wood can through sanding and re-sealing
- Replacement siding can be very hard to find.
- Is no longer considered aesthetically pleasing
Damage and deterioration are of upmost concern. Damage to this siding can lead to structural and health hazards. Keeping the siding clean and in good condition are both important. Asbestos cement is fairly brittle and can be easily damaged by impact. Damage to the siding can also be a moisture intrusion concern. Any damaged areas should be repaired as soon as possible. Specific non-asbestos fiber cement products are on the market today that were manufactured specifically to repair asbestos cement panels.
In summary, having asbestos cement siding on your home is not a death sentence by any means. With the right maintenance and repair program this siding can last many, many years with no issues.
As always, I hope you took some value from this post and if you have any home related questions, please let me know at the email address below.
Aaron M. Zuehlke is the owner and inspector at Zuehlke Inspection Service, LLC, a full-service home inspection company serving Southern Wisconsin. Specializing in Home inspection, Radon Testing, Mold Testing/inspection, Residential Thermal Imaging, and Manufactured Home Foundation Certifications. He also manages several rental properties through Zuehlke Properties, LLC. He can be reached by email at Aaron@Zuehlkeinspections.com or by calling the office at 608-931-7485.