Vulnerable Siding Materials 

Every so often, somebody invents a siding material that appears to be a good bargain, and ends up being a problem. Some of these materials disappear with changing architectural standards, and others hang around for decades. In our area, the four most common sidings we see as concerns are Insulbrick, Compressed Fibre Sidings, EIFS (Exterior Insulation and Finish Systems or synthetic stucco) and Asbestos Cement Siding

Insulbrick is a paper based, tar impregnated, granular faced material that was popular from 1920 to 1950. This material can appear as brick, stone, metal siding or shingle. The pattern on the surface is simply embossed. The product burns extremely well, has seam related water penetration problems, and of course, can no longer be purchased, so repairs to small areas are difficult. Some insurance companies have been reluctant to insure Insulbrick sided houses, because of the increased fire concerns.

Compressed Fibre siding materials are probably here to stay. These materials started in the 1970's and have undergone several iterations in design and execution since. Many of these products swell and delaminate as water penetrates. Rarely are horizontal and vertical seam joints sealed properly by installing contractors. Embossed surface patterns often mimic traditional stucco or wood siding. The newer types are apparently manufactured with waterproof glues, and if so, should stand up for longer periods of time. Only time will tell! In the late 1980's several major forestry companies had premature failure of these products that resulted in lawsuits and premature endings of the production of such materials. We still occasionally come across installations of these, and are hard pressed to be positive about the future performance of these materials.

EIFS was first developed after the second World War, in an effort to insulate and cover much of Europe that had suffered so much damage. The system performs very well on this type of masonry construction.

In the early 1980's, the technology was exported to North America, where it was applied to our conventional wood frame construction. The experiment has had some notable disasters. Since there is no drainage system in an EIFS wall, any water penetration will rot the structure. In the older masonry style wall, this water penetration could actually drain through the wall without damage. Houses in Ontario built with EIFS up to 2003 were not required to have any system to accommodate this water. It is important to note that any wall system will leak water if exposed to driving rains. Unfortunately, the problem was attributed to windows and doors for many years, and there are still thousands of these homes in our area requiring substantial repair to stop this problem.

As home inspectors, we are limited in our ability to determine the condition of structural elements that are not visible. For this reason, when you consider purchasing a synthetic stucco house, you should also consider a more involved inspection of the stucco. This type of inspection can be done with an infrared camera. The camera reads surface temperatures of the wall and shows where water penetration is occurring. This is beyond the scope of our inspection, and is typically performed by a specialist called a thermographer.

Asbestos cement siding (commonly called John Mansville siding) is a mixture of cement and asbestos fibre. This material has proven to be very durable. Since the asbestos is encapsulated, the health risk is minimal. Cutting or grinding can release fibres, so this should be avoided. Removal and disposal of this material has become more expensive as it is listed as a hazardous waste. The panels often crack or chip particularly at corners and holes, and since they are no longer available this can be a cosmetic concern. Actual problems with the siding performance are almost unheard of.