Fire retardent OSB

[Mark Nicholet]

Is fire retardent OSB typical in duplex dwellings? I find lots of FRT sheathing (plywood) in older duplex(s). I am pretty sure the blackness I found todayis mold/mildew although I want to be sure it is not charcoaling. Thanks everyone and long live NACHI

[Brian A. MacNeish]

Originally Posted by mnicholet

Is fire retardent OSB typical in duplex dwellings? I find lots of FRT sheathing (plywood) in older duplex(s). I am pretty sure the blackness I found todayis mold/mildew although I want to be sure it is not charcoaling. Thanks everyone and long live NACHI

Looks like mould! Is it active now or was it just in the first year or so while the building dryed out from damp wood/concrete and excess mositure migrated to the attic.

I tell clients to check the attic in colder winter weather and call me if there is excess condensation/frost on the sheathing.....then we can work on the causes.

[jkogel]

There are attic moulds that are green or white when active and leave a black stain like in your pics after they die. Active molds of any colour can be wiped off with a finger, so that's a good test. Be careful scaring people when there's just a bit of old stain on the OSB. Call for improvements to ventilation if the soffits are blocked, weatherstrip seal on the hatch, stuff like that.

John Kogel
www.allsafehome.ca

[Jeffrey R. Pope]

What makes you think it's "fire-retardant" (resistant) OSB, as opposed to standard OSB?

[Mark Nicholet]

Originally Posted by jpope

What makes you think it's "fire-retardant" (resistant) OSB, as opposed to standard OSB?

I havent had much experience with Fire retardent OSB. I have seen quite a bit of FRT plywood that is deteriorated (looks black with white charcoaling). Just wanted to know if this new fire retardent OSB ( http://www.flamedxx.com/ ) does the same thing as FRT plywood deterioration.

[Mark Nicholet]

Originally Posted by jkogel

There are attic moulds that are green or white when active and leave a black stain like in your pics after they die. Active molds of any colour can be wiped off with a finger, so that's a good test. Be careful scaring people when there's just a bit of old stain on the OSB. Call for improvements to ventilation if the soffits are blocked, weatherstrip seal on the hatch, stuff like that.

John Kogel
www.allsafehome.ca

It is my understanding that mould (dead mould) can re-activate under the right conditions.

[ccurrins]

Originally Posted by jpope

What makes you think it's "fire-retardant" (resistant) OSB, as opposed to standard OSB?

Asked again.

[jkogel]

Originally Posted by mnicholet

It is my understanding that mould (dead mould) can re-activate under the right conditions.

Moisture, temp and food. There are mold spores in the air.

[Mark Nicholet]

Originally Posted by ccurrins

Asked again.

The charcoaling/deterioration of FRT plywood sheathing sometimes blends in with mold/mildew staining. I am curious if anyone has had experience with fire retardent OSB and if it blackens the same way as FRT plywood sheathing does when it starts to deteriorate from high attic temperatures.

[Marcel R. Cyr]

Originally Posted by jpope

What makes you think it's "fire-retardant" (resistant) OSB, as opposed to standard OSB?

Jeff, at least we know the product was manufacturered in 1996 August, but I do not see the Class "A" stamp anywheres.

Marcel

[Jeffrey R. Pope]

That's why I asked

[jkogel]

Originally Posted by mcyr

Jeff, at least we know the product was manufacturered in 1996 August, but I do not see the Class "A" stamp anywheres.

Marcel

It is Exposure 1 classification, which is French Canadian for Class A. Just kidding, Monsieur Marcel.

http://www.osbguide.com/pdfs/EL812.pdf

[Marcel R. Cyr]

Bonsoir, French Canadian? No Franco-American Yes.

I think that is just a fancy word for mutt in the Lingual World. ha. ha. That's what happens when brought up to close to my Canadian friends of New Brunswick.

Marcel

[Carl Brown]

OSB = Mold candy

[Marcel R. Cyr]

Originally Posted by cbrown1

OSB = Mold candy

And comes in colors too!

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Brown mold on plywood roof sheathing



Marcel