I have never seen this type of sheathing. It appears to be sheet rock laid on 1 X 3 lath, with some type of tar backed paper, on top of this is plywood. Any ideas? House is sixty plus.
I hope the photo works, my first at trying to send a photo.
Thank you.
I found this for you here that relates to the same thing but shows the gypsum layer under the wood underlayment.
Local jurisdiction mandated probably? I would check with the AHJ in your area.
http://www.gypsum.org/pdf/GA-276-05.pdf
Marcel :)
Thanks! I never seen this type of sheathing in 32 thirty two years of firefighting.
So after reading that, is it a single family or multi?
That’s proof it works! 
BTW, home inspection must seem pretty relaxing for you. Are you ever tempted to take your ax to a wall?
Do you have any ladder safety tips to pass on?
John Kogel
www.allsafehome.ca
Single family!! Nothing better than the smell of smoke and the sound of breaking glass!!!
Always tie the ladder in!!!.
Mine would be to not use metal ladders ,and use proper ladder angle.
slide hands along rails, rather than hand by hand on rungs.
Put ladder 3 rungs higher than the gutter and do not climb the ladder in front of the house in case you leave marks.
Make sure you’re wearing gloves if your sliding your hands down a fiberglass ladder. Those splinters can be worse than wooden ones.
Jeff
I don’t like the idea of sliding hands along the rails, I think that’s a bad practice. Granted, holding side rails is how it’s shown in the picture on the OSHA site, but my personal experience with OSHA and my opinion is that a few of their methods (like ladder climbing and nailing cleats for scaffolding to walls) are wrong.
If you grasp the rungs you can catch yourself if you slip, even with one hand. If you’re holding onto a side rail, chances are you won’t, you’ll fall.
To descend safely- I believe more accidents happen while descending- you don’t release your grasp on the upper rung until you have a grasp on the next rung down. With 30 years as a carpenter, I’ve caught myself a number of times this way. Never had a serious fall.
The safest way to climb or descend is to maintain three-point contact… you only lose contact with the ladder with one foot or one hand at a time.