# Mould In The Attic



## new2itDom (Dec 1, 2017)

Hey guys,

I am renovating my place i just moved into in Toronto, Canada and I was cleaning up the wiring in my attic. I noticed where one of the plumbing drain stacks comes through the roof, the pipe is frosted and there is mould forming up the roof plywood.

Im planning on getting new shingles installed in the spring, but for the pipe, am I safe to work beside that mould with a mask on. I was thinking of getting a can of spray foam for where the pipe comes up and insualating the pipe. I hear drips from the 1st floor ceiling everytime we shower. I guess from the melting frost on the stink pipe.

Just worried about the mould and working so close to it in tight quarters. what would you guys do?


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## Nealtw (Jun 22, 2017)

You have to much moisture in the attic, if it doesn't condense on the pipe it will condense somewhere else.
The area over the exterior wall should look like this picture. Air chutes from the soffet area to allow air flow. A chunk of batt insulation to insulate the top of the wall and keep the loose insulation out of the soffet. 
I would bet that your soffet is full of insulation and stopping air flow. Along with that there is a min. of vents you need near the peak to let warm moist air out.


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## user_12345a (Nov 23, 2014)

Do you by any chance have a bathroom exhaust fan venting into the attic?

If yes, that must be vented outside. That alone can cause mold growth.

If you don't have one, i would encourage you to get one installed - properly, that is.

By controlling bathroom moisture, you reduce the amount of moisture going into the attic.

Make sure you have open soffit vents (if u don't look at getting a gable vent) and have enough roof ventilation.

Look into air sealing the entire attic. Insulation needs to be moved or removed to do this properly.

*About sealing around the plumbing stack:*



Plumbing stacks move at the house shifts, especially when the temperatures changes.

Spray foam gets brittle as it ages and the seal will break over time if you use it due to movement.

You need something flexible.

People have used plastic vapour barrier around stacks to allow for movement.


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## new2itDom (Dec 1, 2017)

Nealtw said:


> You have to much moisture in the attic, if it doesn't condense on the pipe it will condense somewhere else.
> The area over the exterior wall should look like this picture. Air chutes from the soffet area to allow air flow. A chunk of batt insulation to insulate the top of the wall and keep the loose insulation out of the soffet.
> I would bet that your soffet is full of insulation and stopping air flow. Along with that there is a min. of vents you need near the peak to let warm moist air out.



WOW, that looks nice. My attic just has loose fill and poorly designed ventilation.

If I fix the ventilation problem, will the mould stop forming?


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## new2itDom (Dec 1, 2017)

user_12345a said:


> Do you by any chance have a bathroom exhaust fan venting into the attic?
> 
> If yes, that must be vented outside. That alone can cause mold growth.
> 
> ...


No bath exhaust at all, need to put one in. I will try sealing that pipe, Ive been sealing the electrical with that method right now.


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## Nealtw (Jun 22, 2017)

Hopefully you don't have a lot of mold but it should be dealt with. 
https://www.thisoldhouse.com/how-to/how-to-clean-attic-mold


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