L-P innerseal siding was the oriented strand board (OSB) siding that probably received the most negative media coverage and, among other manufacturers, was involved in a huge class-action lawsuit and a payout to consumers. This Louisiana Pacific product went off the market, officially, in the late 1990's. Fact is, as most inspectors will tell you, the jury is still out or lukewarm regarding even the newer generations of OSB sidings. My experience is that, yet again, they are not all that durable in a damp climate like here in Washington.
Below are some recent photos of L-P innerseal siding that is over ten years old. They were taken recently and show OSB siding that is going down for the count. At a house, the first problem a person might see would be darkness, swelling or de-lamination, often at the bottom edge of the siding. Buckling, waviness, is common too and that can also be related to installation errors.
The photos below are the end stages as the siding goes south. Once it gets to the condition, even in photo one, there is no going back. This first photo is a heavy buildup of algae or fungus, call it converting to "green" building. The next picture is a heavy accumulation of fungus, again at that vulnerable lower edge. The third picture is what we need the mycologist for -- mushrooms are growing on the siding and that is never a good thing. I read somewhere that oyster mushrooms, like you can buy in the store, grow on wood. Wonder what these are? I can send you some if you want to try them.
If you have ever wondered why many inspectors warn that OSB siding, or other compostion wood sidings, are susceptible to moisture damage, these photos tell the story pretty well.
Steven L. Smith
Bellingham WA Home Inspections