Particle board roof sheathing, always a bad idea, but...

…when did it become a defective condition? In an older house, if by some miracle the majority is intact, what can you say besides, “Particle board lacks strength and stability when exposed to moisture and it’s installation as roof sheathing was an extremely poor choice.”, and “You should be diligent in the future in taking action to prevent roof leakage.”?

Edit: Partially answering my own question, but I’m still interested in hearing what anyone else has to say.

Actually, it’s acceptable by the IRC:

803.3.1 Identification and grade.

**Particleboard roof sheathing shall conform to Type 2-M-W as set forth in ANSI A208.1 and shall be so identified by a grade mark or certificate of inspection issued by an approved agency.

**So here’s what I came up with:

[Particle board, non-approved type- SE]]Particle board installed as roof sheathing had no grade mark visible. Particle board in modern homes is required to be visibly marked as ASTM type 2-M-W. If not of a type approved for use as roof sheathing, particle board strength and stability when exposed to moisture is significantly lower than that of plywood or oriented strand board (OSB) more commonly used for this application. The Inspector was unable to determine whether this material is structurally adequate and strongly recommends that before the expiration of your Inspection Objection Deadline you have the particle board roof sheathing evaluated by a structural engineer.


[Particle board, approved type]]Particle board was installed as roof sheathing. The particle board was visibly marked as type 2-M-W, considered aceptabe as roof sheathing by generally-acceptd modern standards.

Sounds good to me.

Only thing else I might add would be:
Subject to warping and uneven roof surfaces.
This may be considered a visual or cosmetic condition but is likely to accelerate to a structural concern should moisture come into contact with materials…

I’m trying to figure out:
If it’s rated for roof sheathing, how comparable in strength and durability to plywood and OSB is it? I can’t find anyone who makes it. I can’t find anyone who’s ever even heard of particle board ASTM-rated for roof sheathing.

If you are talking about standard particle board such as cabinet material, I seriously doubt you will ever find a reference for being rated for roof or wall sheathing. Not approved for this in FL, and a really bad choice. I’ve seen particle board panels ready for use as storm shutters before…lol.

No Brad, I’m talking about particle board with an ASTM rating as roof sheathing! I don’t believe this stuff actually exists, even if there is a standard for it. While I was researching I stumbled onto forums where roofers :—):—):—):—) were recommending it!

Interesting. If you find a link on the product, I would like to know more about it, thanks.

Every roofer here uses OSB. Wood is getting to be expensive, so alternatives are being discussed. Most all county codes are different, and many do not allow particle board for anything. I have yet to see any used for any construction purpose here in KC, at least yet.

Nice verbiage by the way, what about adding

“had no visible grade mark or certificate of inspection issued by an approved agency”

Now what about its use at open soffits

[FONT=Comic Sans MS]“The use of particleboard at open soffits is not recommended. Particleboard lacks the performance needed for direct exterior exposure; a better performance material for this application would be wood board or exterior grade plywood CDX”[/FONT]

Same here, sounds interesting.

I know in PA, we’d call OSB, particle board…maybe it’s a language thing.


are you talking about this stuff? I am asking cause there was another thread where someone called it particle board…I have walked on it where it was spanning 4 feet and it held my 220-230lbs just fine

I don’t know, Mike. They don’t call it particle board on that website.

LOL, I bet 80-90% of inspectors or contactors who see it in the field (especially after water damage ) describe it as “some kind of particle board” …I have no clue what it “really” is, I just have seen it before and dealt with it and noticed a different thread was calling it particle board and then saw this one. Just thought I would share as it is the only thing I have seen that is “particle board like” and used as roof decking (well legally)