Drywall in the attic

[John H. Cooper]

Today as I was inspecting a house I came across a section of OSB sheathing covered with water resistant drywall. (see attachement). The seller indicated that they had problems the previous winter with icicles, and the builder had come back in and added ventilation and apparently this drywall? The only thing I can figure is that they thought it might insulate the bottom of the sheathing some? I couldn't see any deterioration of the sheathing in the immediate vicinity, and no evidence that they were trying to encapsulate something. Any ideas?

[Barry Adair]

Moisture/condensation issues are not remedied by the installation of WR gypsum, that I'm aware of and remember it's water resistive not water proof.

Were there any breaches, vents, ducts in the ceiling or top plates around this area?

I'd be willing to bet if frost/icicles were forming there this year, they will next year, as well.

Until the moisture is controlled nothing else will be alleviated.

Look for the same freeze issues occuring...

[David P. Valley]

That drywall will turn to MOLD eventually.

There are remedies for ice damming and adding drywall is just plain stupidity.

Ice damming is caused from improper R-value of insulation and improper ventilation.

[ldapkus]

There may be mold that is concealed by the drywall.

[John H. Cooper]

Ok, I got to the bottom of this one. This was an attached home... a "townhome." This wall was the common wall, with a valley between the two units. Basically two gable roofs with a horizontal valley in between. Not a very BRIGHT way to construct a roof in Alaska. They then installed a inverted crickets on the front and rear to create two additional valleys to cover that one long horizontal valley.

The bottom line is, they installed fire resistant sheathing in the roof on both sides of the 2 hr rated wall so they would not have to install a parapet. However, the two units were not aligned with each other. This unit extended past the front wall of the other unit. The builder did not install fire resistant sheathing where the roof extended past the other unit. The city inspector decided that this did not meet the requirements of IRCR317.2.2.2 So, in accordance with the same section, they mitigated it with "one layer of 5/8-inch (15.9 mm) Type X gypsum board is installed directly beneath the roof decking or sheathing for a distance of 4 feet (1219 mm) on each side of the wall."

So, it is code. Not good code, and not even the wy I would have interpreted the code, but I am not a code inspector. I did note in the picture that the adhesive looked red. Well it is. It is fire rated. Thank you city inspectors.

[David P. Valley]

Originally Posted by jcooper2

Ok, I got to the bottom of this one. This was an attached home... a "townhome." This wall was the common wall, with a valley between the two units. Basically two gable roofs with a horizontal valley in between. Not a very BRIGHT way to construct a roof in Alaska. They then installed a inverted crickets on the front and rear to create two additional valleys to cover that one long horizontal valley.

The bottom line is, they installed fire resistant sheathing in the roof on both sides of the 2 hr rated wall so they would not have to install a parapet. However, the two units were not aligned with each other. This unit extended past the front wall of the other unit. The builder did not install fire resistant sheathing where the roof extended past the other unit. The city inspector decided that this did not meet the requirements of IRCR317.2.2.2 So, in accordance with the same section, they mitigated it with "one layer of 5/8-inch (15.9 mm) Type X gypsum board is installed directly beneath the roof decking or sheathing for a distance of 4 feet (1219 mm) on each side of the wall."

So, it is code. Not good code, and not even the wy I would have interpreted the code, but I am not a code inspector. I did note in the picture that the adhesive looked red. Well it is. It is fire rated. Thank you city inspectors.

Now that's ridiculous. Drywall installed in an area that is susceptible to Mold. Let's install drywall to meet fire code but let's not worry about the mushrooms that accumulate all over it in a year a two.

Go figure.

[asargisian]

Remember this, if the city inspector says it's ok, then it's ok...(ya right) do you think that the owner can have a law suit against the city officials for a bad call on a no knowledge idiot city inspector. ???? Any time a city official give an ok, for what ever the reason he was there in the first place..Get it in writing.

Invest in the IRC & IBC books it's worth the investment..Paperback $80.00