Mold removal

christiesternerz · 10-13-20, 06:51 AM

I already confirmed that my attic has a mold. What is the best solution for this?

pinballlooking · 10-14-20, 12:20 AM

Take a picture to show us what you are dealing with.

WillyP · 10-14-20, 08:30 PM

usually when dealing with mold, the first thing you need to do is fix whatever is causing the moisture. In the attic it probably has to do with poor ventilation (or a leak). If you cure that, in something like an attic, the mold will practically fix itself. Of course you still need to remove it, but making it dry will stop it from growing.

mk1st · 10-26-20, 12:29 PM

Any mold growth means you have a water problem.
It will either be a 1)water leak or 2) condensation (in rare cases it could be both)

1) A water leak will usually be pretty easy to determine and the mold will be confined to only that area: is the roof in poor condition?, is there a flashing penetration such as a vent or chimney that's failing. The damage may not show up though right under the leak as water can wick along framing members. Fix the ongoing leak and the mold won't be able to grow. Old mold, once it's inactive, is not harmful to most people and if you don't go in the attic I'd not worry about it. Definitely DON'T try to "kill the mold" with bleach!!

2) If you see mold over a wide area of the underside of the roof and framing members then you have a condensation problem, most likely because you have air leaks from your living space up into the attic. In the winter the warm moist air from below will condense on all of the cold surfaces in the attic (insulation won't stop the air movement) Air sealing the attic floor is the solution. Get an energy audit (mainly that's a blower door test with infra red imaging) and you'll get a good idea as to how much air sealing is needed. Once the air sealing's done then you can insulate with confidence.

I know roofers will beat me up over this but this problem (if it's condensation) is NOT because you don't have enough attic venting. A properly air sealed attic needs very little venting - really just to allow expansion and contraction of the air in there when it changes temperatures. Good attic venting is fine but it's not the fix-all that roofers would have you believe (partly because roofers never go in the attic and want the easy work of adding vents).

Now....off to set up my blower door.

MN Renovator · 10-26-20, 05:59 PM

I agree that you don't need a pile of attic venting, but you need some to allow the incidental moisture in winter to flow out. Moisture flows readily and usually it doesn't take much ventilation to remove the amount of moisture that ends up in an attic through incidental air bypasses. If you have attic mold, you've likely got a larger air bypass than just loose wooden top plates, small holes drilled for wires, or a hole cut for a plumbing vent stack. If there isn't a roof leak, most likely there is something like a broken or missing bathroom vent duct, a grossly oversized hole cut for a plumbing stack(square hole for a round peg or someone likes their sawzall too much), can lights(hate these things, there are insulated versions and gasket retrofits that make this a better situation though), or a soffit chase. ..or perhaps you have a cape cod house and a knee wall is involved which could have all sorts of leaks in tons of places, especially the upstairs floor bypass.

When I talk about ventilation, I'm talking about free flowing vents, not powered vents because those make the problem worse by creating a vacuum and sucking the moist and warm interior air into the attic.

I also noticed you are from Spokane. I assume this is Washington? There is a ton of wet there and I know from my friends in Portland and Seattle that their roofs essentially are caked with algae/moss because they are never dry, I don't know if there are any specific building design or science that should be different for your climate and type of house. In my region, the air is generally far enough away from the dew point to where it doesn't take much to keep the attic moisture down. This isn't a livable attic space, is it? How much mold? any particular spots it's common in, throughout the entire attic? ..or above the attic hatch or a bathroom specifically?

10-13-20, 06:51 AM	#1
christiesternerz Lurking Renovator Join Date: Apr 2020 Location: Spokane Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts	Mold removal I already confirmed that my attic has a mold. What is the best solution for this?

10-14-20, 12:20 AM	#2
pinballlooking Super Moderator Join Date: Jun 2013 Location: SC Posts: 2,767 Thanks: 162 Thanked 531 Times in 435 Posts	Take a picture to show us what you are dealing with. __________________ Current project Aquaponics system , Passive Solar Greenhouse build To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Solar Install 12.5 Kwh- To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Mini Split installs - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. EV Chevy Volt - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

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10-14-20, 08:30 PM	#3
WillyP Lurking Renovator Join Date: Jul 2020 Location: Virginia Posts: 22 Thanks: 4 Thanked 2 Times in 2 Posts	usually when dealing with mold, the first thing you need to do is fix whatever is causing the moisture. In the attic it probably has to do with poor ventilation (or a leak). If you cure that, in something like an attic, the mold will practically fix itself. Of course you still need to remove it, but making it dry will stop it from growing.

10-26-20, 12:29 PM	#4
mk1st Friend of Entropy Join Date: Feb 2010 Location: Fort Atkinson Wi Posts: 17 Thanks: 1 Thanked 5 Times in 2 Posts	Any mold growth means you have a water problem. It will either be a 1)water leak or 2) condensation (in rare cases it could be both) 1) A water leak will usually be pretty easy to determine and the mold will be confined to only that area: is the roof in poor condition?, is there a flashing penetration such as a vent or chimney that's failing. The damage may not show up though right under the leak as water can wick along framing members. Fix the ongoing leak and the mold won't be able to grow. Old mold, once it's inactive, is not harmful to most people and if you don't go in the attic I'd not worry about it. Definitely DON'T try to "kill the mold" with bleach!! 2) If you see mold over a wide area of the underside of the roof and framing members then you have a condensation problem, most likely because you have air leaks from your living space up into the attic. In the winter the warm moist air from below will condense on all of the cold surfaces in the attic (insulation won't stop the air movement) Air sealing the attic floor is the solution. Get an energy audit (mainly that's a blower door test with infra red imaging) and you'll get a good idea as to how much air sealing is needed. Once the air sealing's done then you can insulate with confidence. I know roofers will beat me up over this but this problem (if it's condensation) is NOT because you don't have enough attic venting. A properly air sealed attic needs very little venting - really just to allow expansion and contraction of the air in there when it changes temperatures. Good attic venting is fine but it's not the fix-all that roofers would have you believe (partly because roofers never go in the attic and want the easy work of adding vents). Now....off to set up my blower door.

10-26-20, 05:59 PM	#5
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 934 Thanks: 41 Thanked 114 Times in 88 Posts	I agree that you don't need a pile of attic venting, but you need some to allow the incidental moisture in winter to flow out. Moisture flows readily and usually it doesn't take much ventilation to remove the amount of moisture that ends up in an attic through incidental air bypasses. If you have attic mold, you've likely got a larger air bypass than just loose wooden top plates, small holes drilled for wires, or a hole cut for a plumbing vent stack. If there isn't a roof leak, most likely there is something like a broken or missing bathroom vent duct, a grossly oversized hole cut for a plumbing stack(square hole for a round peg or someone likes their sawzall too much), can lights(hate these things, there are insulated versions and gasket retrofits that make this a better situation though), or a soffit chase. ..or perhaps you have a cape cod house and a knee wall is involved which could have all sorts of leaks in tons of places, especially the upstairs floor bypass. When I talk about ventilation, I'm talking about free flowing vents, not powered vents because those make the problem worse by creating a vacuum and sucking the moist and warm interior air into the attic. I also noticed you are from Spokane. I assume this is Washington? There is a ton of wet there and I know from my friends in Portland and Seattle that their roofs essentially are caked with algae/moss because they are never dry, I don't know if there are any specific building design or science that should be different for your climate and type of house. In my region, the air is generally far enough away from the dew point to where it doesn't take much to keep the attic moisture down. This isn't a livable attic space, is it? How much mold? any particular spots it's common in, throughout the entire attic? ..or above the attic hatch or a bathroom specifically?