Best Way to KILL Mold in Attic???

Closed Thread

  #1  
Old 12-13-11, 05:19 AM
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 245
Best Way to KILL Mold in Attic???

Hello everyone! I recently started a thread trying to find out why I suddenly have mold in the attic after 112 years without.
http://www.doityourself.com/forum/ro...-now-help.html

It turns out it was me. No good deed goes unpunished. On the second floor we have kneewalls and slanted ceilings for the length of the house. The prior owner had insulation blown in the the bays in the slanted part of the ceiling and over the flat part. (see diagram in link above).

The genius that I am decided that 4" of settled insulation wasn't enough, so I rolled R-19 over the blown in insulation and partially into the cavity of the slanted part of the ceilings. I did this last year and now I have mold!!! Specifically it is on the sheathing on the north side of roof.

Last night I pulled the fiberglass insulation back from the sheathing and the sheathing was moist, as was the insulation. Below the R19 that I stuffed in there was the original blown in stuff....IT WAS DRY!!! So clearly I inhibited airflow to the point where I allowed condensation to form and mold to grow.

So I will be removing the R-19 where it makes contact with the sheathing. But the million dollar question is ..... what is the best way to kill the mold??? The mold hasn't been there long, my guess is that it is new as of this fall/winter. It is the white, somewhat chaulky/fuzzy variety.

I've heard of 50/50 bleach/water but I imagine in a "not-so-ventilated" attic the fumes would get pretty bad. What about Hydrogen Peroxide? No fumes really. I test sprayed some on last night and the mold started fizzing and bubbling like peroxide on a dirty wound, so its doing something. I'll check it tonight to see how well it did cleaning it up.

I know you can never 100% kill mold on a pourous surface but I've got to do something. Starting next year I will make corrective steps to improve the soffit ventilation as part of a remodel.....but I don't want a fuzzy attic in the mean time.

Your advice?!?!!? And sorry for the long post, I've had alot of coffee.
 
Sponsored Links
  #2  
Old 12-13-11, 03:19 PM
Member
Join Date: Oct 2006
Location: Wilmington
Posts: 4,219
Mold is a part of our nature, it is here, all it needs is a nurturing atmosphere. Warm Moist air in an attic with poor ventilation is perfect. Improve the ventilation with soffit/ridge vents!!! Add insulation to at least R30, or 12-14".

Fill the existing ceiling joist bays to full, then switch the direction of the insulation layer. This covers a lot of the missed areas before. And do it agian, in the opposite direction.

To get rid of existing mold, a solution of 10:1 water:bleach, is the formula I keep reading about. It works for me.
 
  #3  
Old 12-13-11, 03:56 PM
Join Date: Sep 2011
Location: USA
Posts: 13
I would make sure all the ventilation is set up correctly, possibly get a dehumidifier. I use a bleach and water solution. Take action now before you have to call someone over to professionally do it.
 
  #4  
Old 12-13-11, 04:12 PM
airman.1994's Avatar
Member
Join Date: Dec 2005
Location: VA
Posts: 5,729
Likes Received: 3
Best way would be to use Foster 40-80.
 
  #5  
Old 12-14-11, 06:51 AM
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 245
Thank you everyone! Just to give you guys an idea of what my construction looks like (some of you may have already seen this on the original thread)....



There is no way to put soffit vents in right now. The ceiling bays are just plugged with blown in insulation. When I remodel and provide a proper air channel I will install the soffit vents. I currently have a ridge vent. Also, the slanted ceiling part, beiing full of blown iin insulation is probably about R19. The flat part of the ceiling has 6" of blown in plus one layer of R19, so it should be at least R38.

I am going to "un-do" some of the work I did and get the R19 away from the sheathing. Where the R19 hits the sheathing and above to the ridge vent is where there is mold. Its not everywhere, its more spotty and sporatic, but consistant. Its only on the North side as well.

I will be removing the R19 near the sheathing over the next few days. I then want to spray something on the mold to try and kill it. I'll put some fans up in the attic to provide some airflow so that the moisture from whatever I spray doesn't hang around too long.

So far I've got these opinions:
- Foster 40-80: Foster
This seems promising. I like using professional products just because I feel like they know better about dissenfecting than I do. I will look into buying this.
- Bleach solution: This will kill the surface stuff but maybe not the stuff in the pores. I can't stand the smell of bleach and this is an "almost" enclosed area....and I don't have the appropriate filters for my respirator.

ANd then there is the 3% Hydrogen Peroxide which I mentioned earlier. Does anyone have experience with this for mold remediation? I did a search on the net and the greenies are all about this or vinegar instead of bleach since it is more "earth friendly". I keep hearing how it works better too. Any truth to this?
 
  #6  
Old 12-14-11, 08:25 AM
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 19,221
Likes Received: 34
I use peroxide for removing blood from carpet and other soft materials but have never tried it for mold. Despite the smell, bleach is a tried and proven method of killing mold so I stick with it.
 
  #7  
Old 12-14-11, 08:38 AM
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 245
I sprayed the peroxide on one small section, we'll see how it goes. It bubbled like crazy on the moldy spots. I'm going to go with bleach though....no sense half-a$$ing it.

I'll keep an eye on it and if needed I'll by some of that Foster 40-80 stuff, as I'm sure it will work great. If I could buy it locally I would use it over bleach but the shipping costs make it a bit prohibitive.
 
  #8  
Old 12-14-11, 12:21 PM
Member
Join Date: Jan 2005
Location: ny
Posts: 60
I used an acid based product cal-brite it was sold by a local pest controle Caltex International - Cleaning and surface restoration business opportunities (one of the few refrences i found online) amazing stuff, spray it on and the mold just disappears. I then used a borate solution to prevent further growth (i used termite prufe) but as others have said you need to stop the moisture buildup.


I did try bleach but found it didnt work well on the plywood and was labor intensive.
 
  #9  
Old 12-14-11, 03:31 PM
Member
Join Date: Oct 2006
Location: Wilmington
Posts: 4,219
You described your problem perfectly, poor ventilation. You do not have to remove insulation, but you do need soffit ventilation and an air space up along the roof sheathing. There are ways to do that without removing insulation. AND, plug any places thwere warm. moist air escapes from the house into the attic, wire holes, fan ducts, gaps in insulation, etc.
 
  #10  
Old 01-13-12, 01:15 PM
Member
Join Date: Jan 2012
Location: USA
Posts: 1
lupi2279... is this what you were referring to for the cal-brite:Nu-Calgon Cal-Brite Coil Cleaner, Gallon

Thanks!
 

Last edited by the_tow_guy; 06-22-12 at 09:25 AM.
  #11  
Old 01-16-12, 05:01 AM
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 245
Thanks for the responses everyone! I'll give an update. About a month ago I went up and sprayed a 50/50 mixture of bleach and water. It killed the mold and cleaned everything up. I've been keeping an eye on things up there and even though I got the insulation off of the sheathing there is still condensation. It is very little when compared to before but it is still there.

I have pine planking going across the rafters and plywood on top of the planking. Before, mold was on everything on the north side. Now I just get condensation on the plywood in the spaces between the pine planking.

This spring I plan to gut/remodel the bathroom which will give me access to 60% of the north side of the attic. I'll properly kill/treat any remaining mold and install proper venting. The remaining 40% of the attic I will fix from the attic. I will suck out the blown in insulation from the bays and install proper venting and insulation. It will be a real PITA doing it from the attic but it will save me from creating a HUGE mess inside the house.

Thanks again!
 
  #12  
Old 01-22-12, 02:58 PM
Join Date: Jan 2012
Location: USA
Posts: 1
everything that i ve read about mold remediation suggests that the benefits of clorox are far out weighed by the harmful side effects. there are many products out there that are much safer, microban, concrobium, etc. i ve used concrobium several times available at home depot probably lowes too. add some raft r mates at eaves to allow air flow and soffit vents. i'm currently doing the same thing right now in a cape cod. previous owners had r19 in rafters with 2 roof vents and gable vents, no soffit vents. everywhere the insulation was pieced there was condensation.
 
  #13  
Old 01-22-12, 03:44 PM
airman.1994's Avatar
Member
Join Date: Dec 2005
Location: VA
Posts: 5,729
Likes Received: 3
I would not say Microban is safer. How many lawsuits they be in
 
  #14  
Old 01-22-12, 07:01 PM
Member
Join Date: Jan 2011
Location: United States
Posts: 2,446
I recently within a few weeks saw an episode of Ask This Old House where they used dry ice to remove mold. The dry ice was professionally sprayed on with a high powered sprayer something like a sand blaster. When they were finished it had cleaned the wood of the mold. Afterwards I think they used a borate solution and sprayed that on to help prevent regrowth. Tom Silva said though that the owners needed ventilation especially in the soffits. They also needed to either remove or cover up their gable vents since they had ridge venting. Tom Silva also said they needed a better vent from their bathroom fan than allowing it to vent into the attic as it should always vent outside. The video for that episode should be on their website. Good luck in your mold fight it never is a pleasant thing to deal with.
 
  #15  
Old 01-01-13, 04:00 PM
Member
Join Date: Jan 2013
Location: Canada
Posts: 1
BigOldXJ,

We recently purchased an older home which has some attic mold and closely resembles your diagram in that there are no soffit vents and the cavity from the soffits to the attic contain fiberglass insulation - hence very little to no attic intake ventilation. As your diagram illustrates the distance from the attic to the soffits is lengthy (about 8 feet in my case).

I am also thinking about a graduated approach to get air flowing from the soffits. All of my research tells me that you have to resolve the airflow first in order to remove the moisture that will cause mold to return even if you get rid of what is currently present.

One idea is to remove the existing insulation in the enclosed cavities, run a 3 inch pipe (e.g. PVC) from the attic to a new soffit vent and then re-insulate the cavity with loose insulation. Using closed cell spray foam might be better but it is costly. The advantage of this approach is that interior walls do not need to be torn down and replaced. The downside (other than the amount of labor required) is that a lot of pipes will be required to get adequate air flow. My attic is approximately 1000 square feet and my calculation is that I need about 80 square inches of intake ventilation (1000 / 150 X 12).

Another option is to encapsulate the attic by insulating the underside of the roof. Sprayed foam insulation appears to be used in this approach, from what I have ascertained. Existing roof vents would need to be sealed. I am hesitant to go this route as you would never know if roof is rotting due to a leakage on the exterior. In addition, if a roof section does require replacement more foam must be sprayed. There may be other reasons not to go this route.

I would appreciate any feedback on these ideas as the attic is poorly insulated but I feel I must resolve the ventilation issue before addressing this.
 
  #16  
Old 01-09-13, 09:01 AM
Member
Join Date: Jan 2005
Location: ny
Posts: 60
@daduh

I dont think so.

I actually bought it at a a local pest supply/home inspection store Dana Pest Control.

it seems as though caltex distribute through a network of professionals by their website Environmentally safe mold remediation and mold removal business opportunity personally I think their website looks a little sketchy. That said I cant say enough about the calbrite product. sprayed it on w a pump sprayer (use gloves its slightly acidic) and the wood looks new. Scrubbing w bleach did crap. If i remember it was about $30 and it was a 2 part solution. I followed later w Termite Prufe(borate solution) and have had no re-occurance.

heres a pic i found online of the bottle i used Google Image Result for http://inspectapedia.com/mold/Cal_Brite_Client_Photo02304-05-07Zs.jpg
 

Last edited by lupi2279; 01-09-13 at 09:20 AM.
  #17  
Old 03-23-13, 01:54 PM
Member
Join Date: Jan 2013
Location: usa
Posts: 1
I sure wish I could find this Cal-Brite stuff. Not having any luck. Is it discontinued?
 
  #18  
Old 07-15-13, 05:35 PM
Member
Join Date: Jul 2013
Location: Usa
Posts: 1
Cal brite

Myself included. Does anyone know were to purchase the cal brite product?
 
  #19  
Old 09-09-13, 05:05 AM
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 245
Well since this thread doesn't want to die I suppose I'll provide an update.

The problem is obviously ventilation. With just a ridge vent there was no way for cold intake air to make it into the attic. The only way to get that air was getting in was from the house. Warm, moist household air + attic = MOLD.

I installed two gable vents for intake air. Soffit venting would be ideal but impossible due to the construction of the house. I will install a fan on one gable vent connected to a humidistat to exhaust humid air in the winter.

Now an update on the mold. There are some spots where the mold did not die. The bleach spray I did over a year ago was probably not as effective as I would have liked. I didn't have chemical goggles on and that stuff burns your eyes pretty bad! I hurried the job as fast as I could so I'm sure I missed plenty.

Also, bleach is pretty ineffective on a porous surface. There are other more professional products out there that are more appropriate. I just bought a gallon of Fiberlock Shockwave which is a professional grade biocide. Foster 40-80 would have been another good choice but was unavailable locally.

I ended up spraying the surface 3 times, starting at one end of the roof and going back when I reached the other end. The wood is old and dry so the first spray got soaked up pretty fast. The second spray stayed wetter longer. The third spray stayed wet for some time. So I should have adequate penetration.

We'll see, but I'm hoping for the best! I am having insulation blown into the exterior walls so that should prevent warm air from reaching the attic and I'm doing as much air sealing as I can to prevent it further.

That in conjunction with the new attic venting and the powered fan on one side I hope to be done with this problem!!!
 
  #20  
Old 11-17-13, 10:00 AM
Member
Join Date: Nov 2013
Location: usa
Posts: 2
Spraying myself - Hydrogen Peroxide

I've heard bleach doesn't work well for porous surfaces... So I'm planning on going with a 10% hydrogen peroxide + borate solution on my sheathing... Just as if I was dry-ice blasting and worried about running out of oxygen, now I'm concerned about using something that has TOO MUCH oxygen - creating what might be a highly flammable environment in a hot, dry attic. Any advice on that? I'm assuming as the hydrogen peroxide reacts with - anything - it will release the extra O atom and my attic will be flooded with oxygen? Or am I overthinking this?

Plus, is it okay to overspray the flame-retardant-coated cellulous-based insulation with this stuff? It's the blown-in kind, not the pink rollout stuff.

Plus+, is it okay to overspray the insulation with the fiberlock primer/sealer/paint stuff once I treat everything with peroxide? Or should I cover it as best as I can w/ plastic THEN spray? the ceiling isn't very high and it's *very* difficult to get "back in there". Nearly impossible. so if I'm spraying the sheathing, I'm going to be spraying the insulation too, unless I cover it.
 
  #21  
Old 11-20-13, 10:47 AM
Member
Join Date: Sep 2009
Location: USA
Posts: 39
I wanted to add one more recipe for a mold killing formula that works quite well. I'm not sure where I came across this formula, but it is surprisingly inexpensive to make.

The formula is 2 teaspoons per quart of washing soda (not baking soda). This is available in the laundry aisle at the supermarket. Then 1/8 teaspoon of trisodium phosphate per qt. of water--available in the paint section at Home Depot/Lowes, etc. This can be used in a fogger that can be rented from HD, or for smaller jobs I bought a battery powered sprayer designed for RV cleaning. You could also use one of those pump up insecticide sprayers too. The goal is just to produce a really fine mist.

I did one little experiment on a very musty smelling instrument case. I sprayed the case, and allow it to sit overnight, and the next morning the smell was completely gone. I knew I had a winner at that point. This beats the heck out of spending $8-$10 a quart at the local home improvement centers, and does not leave any smell behind like bleach or vinegar. Just be careful about spraying it too heavily or it will leave a white film.

Of course, you have to get rid of the source of the problem or your mold will just come back. This means eliminating the food source and conditions for mold to grow. I suspect all this sounds very simple, but having dealt with mold issues myself, sometimes the hardest part is figuring out where and why the mold is growing. I went for almost a year in my own house smelling mold, and thought that it was coming from the basement. I later came to find out there was a small leak in the tub surround. Every time I showered, a small amount water leaked behind the bathtub, and got into the flooring. Since this was all closed up I never saw any water. When I finally got around to renovating the bathroom, I was totally shocked at the amount of mold! OMG, the floor joists were saturated with water, and since there was floor covering and ceiling covering from the basement, I never saw it. I ended up having to cut out the joist, flooring and the water even seeped into the walls and bottom plate, all of which had to be cut out and replaced.

When I redid the tub surround, I made sure to use concrete backing board, just in case water ever got behind the new tub surround. Again, pretty simple once I found the problem, but I had no idea it was a problem for years. I suffered from respiratory problems, post nasal drip, congestion, lack of energy and brain fog all winter. Mold is nasty stuff. Not everyone reacts to it, but I sure did.

Best,

Troy
 
  #22  
Old 12-31-13, 04:56 PM
Member
Join Date: Dec 2013
Location: United States
Posts: 1
Post Hey everyone

Hi guys/gals,

I just bought my first house in Oct 2013. Im just south of Boston, MA. This thread has been very helpful in giving me some ideas on how to tackle my mold problem.
Heres a description of whats going on and what my attic is like;

Central Air system (With attached humidifier and is properly vented to chimney)
Ridge Vent
No soffit vents from what I can see so far
Windows on the front and back sides of the attic
Leaky Chimney that gets the wood around the chimney wet
Pull-down stairs that fold up into attic when closed
Insulation is this old yellow blown-in stuff, and the pink stuff on top of that
Minimal floor boards

I went up there the other night to check if my chimney leak fixes worked and realized that theres quite a bit of white colored mold forming mostly on the lower half of the roof (more on the north facing side than the south facing side). First thing I thought was that I have my humidifier set too high, so I turned it off until we can fix the problem. Last night I opened both of the windows up there about 3-4 inches to allow some ventilation.
I need to add alot more insulation up there and maybe build an insulated box to cover the stairs, theres alot of openings going into the walls that I need to seal up also.

Anyways, back to the mold. Im definitely going to spray and get rid of it all, but I dont know the best way to go about preventing it from coming back. This is my first time having to deal with something like this and I want to make sure I do it the right way the first time.

Any suggestions??

Thanks!
 
  #23  
Old 12-30-14, 08:01 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 17,727
Likes Received: 2
Old thread ... closed..

Please start new...
 
Closed Thread

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes