Common Fiber Cement Siding Installation Errors


If you are buying or if you own a home built in the 2000’s, it most likely has fiber cement siding. As its name suggests, fiber cement siding is a cement based material known for its longevity and decay resistance. However, like anything, its longevity and resistance to deterioration is only as good as its installation. Manufacturers of this type of siding have provided detailed guidelines as to how to ensure the longevity of their product. If a siding installation specialist knows his/her stuff, he/she will be fully acquainted with these guidelines and will be following their instruction. Unfortunately, this is not always the case. 

My Job: 

My job as a home inspector is to evaluate and identify any defects related to the siding that could result or is resulting in harmful water penetration and leaks. The purpose of the siding is to provide a mostly weather tight cover over the underlying wall and floor components of the home. Any defects that result in these components being exposed to water are reported as needing repair. The following common defects related to fiber cement siding installation are some of those that can result in water penetration. 

1) Missing or Incorrect Butt Joint Details: 

The butt joint is where two pieces of siding meet together on the wall. In general, manufacturers require butt joints to have moderate contact. They highly recommend these joints to be flashed as best practice, but they will allow them to be caulked instead.  The purpose of the flashing and caulking is to prevent water from traveling between the joints and down behind the siding. 


2) Improper Clearances from Surfaces: 

Fiber cement siding can deteriorate prematurely if the siding is in constant contact with water and has no means of drying out. This typically happens where the siding is in contact with surfaces that trap moisture against it. These surfaces include roofs, patios, driveways, porches, and decks. Manufacturers therefore provide clearance guidelines at these surfaces to ensure the longevity of their product. 


3) Missing Kick Out Flashing: 

An all too common installation error is the neglect of installing kick out flashing where a gutter tray ends at a side wall. When kick out flashing is missing, roof drainage that runs down the roof surface along the side wall is typically directed behind the siding, often resulting in hidden wall and floor structure damage.


There are other installation details that can be found missing when inspecting fiber cement siding, but they typically do not result in underlying water penetration and damage. Again, fiber cement siding is a long lasting product as long the installation specialist follows the manufacturers guidelines and best practices. If you are purchasing a home with fiber cement siding or if you own a home with fiber cement siding, it would be my pleasure to help you identify if your home has any of the above problems. When you really want to know, contact Adam Duncan of Duncan Home Inspection Services, LLC.