There's Mold in my Attic! What Caused it and How Insulwise Solves it. 

Thanks so much! It only took a few thousand hours of working in attics to start connecting all of the dots between stack effect, moisture getting into attics from the home (and roof leaks), temperature variables, air sealing, proper ventilation, etc. lol. Glad this helped you!

Hi Russell, you're highly welcome. I am going to be putting together another video for trouble shooting attic moisture issues soon. We had a previous customer who had moisture problems develop in his attic after we air sealed and insulated his attic. After I inspected everything I found that he has drainage issues on his back garage wall and water is coming through is foundation wall. In this case I'm convinced that no matter how well his roof and ventilation measures were functioning, and how well we'd air sealed his attic (we zone tested it using a blower door -- it is VERY well sealed), he'd still be having moisture issues in his attic due to the sheer volume of moisture entering his home via the foundation wall. So, these issues can get complicated. But the moral of the story for all attic mold issues is that the moisture source must first be identified and eliminated before you can hope to permanently solve the issue. Otherwise the mold will simply keep coming back. Thanks! Andy

Hi Dean, glad to hear! I believe there is a lot of misunderstanding out there when it comes to the issue of attic mold. I'd like to think that we've got a bit better grasp on it due Insulwise's building science based approach to retrofitting homes as well as the sheer amount of time that we spend in attics (thousands of hours a year across our staff!). Andy

Thanks J Dee! Andy

We see this in the Pittsburgh area often. Mold companies know how to kill attic mold, but they don't understand what causes it to grow or how to keep it from coming back. Check out this link on our website that explains attic mold, and read what I've written below. www.insulwise.com/pittsburgh-attic-mold-specialists/ 1) Confirm your roof is water tight. If it is then the moisture is coming from your home in the form of air leaks in your attic floor. These need to be verifiably sealed so that the air in your home is no longer communicating with the air in your attic. Very few companies out there understand what this is, why it's necessary, or how to do it properly, so be careful in hiring a company to do this. This is attic air sealing: www.insulwise.com/insulation/air-sealing-insulwise-pittsburgh/ 2) You need to get your attic ventilation right. Attic ventilation needs to be balanced between exhaust (up high by the ridge) and intake (down low at the soffits). If your attic only has exhaust vents than you could be making the problem worse by putting your attic in a state of depressurization...where your attic is effectively sucking air upward from your home. During the winter this air is going to have moisture in it, and you don't want that because moisture is fuel for mold growth. 3) Confirm your intake vents are working by going up into your attic during a bright sunny day and turning off all the lights. Your soffits will either be lit up with daylight (not just a dim crack of light showing) or they won't be. If you have soffit baffles and deep insulation you will need to adjust your vision so that you can peer down the open tops of the baffles. In Pittsburgh perforated soffits are decorative about 90% of the time. The wooden soffits beneath them usually have no holes drilled, so they only "look" like they're working. 4) If you believe that your attic vents are not set up properly, have a roofer calculate your ventilation needs "1/300 rule" and have him install intake and exhaust vents until you are balanced and at the recommended level. Keep calling roofers until you talk to one that can have an intelligent conversation about proper ventilation...many of them can't. 5) Now it's time to kill the mold again. This time it should not come back. 6) Attic power fans often cause more problems than they solve. Knucklehead contractors often install them without realizing that they NEED to have a specified amount of "net free make up air" for intake, or they absolutely WILL pull that air upward from your home. The required amount of Net Free Air for make up air is listed on the box of every power fan that I have looked at. And every roof vent that I've seen sold lists the amount of net free air (NFA) they supply on the side of the box. Also, no attic that I've seen needs any kind of powered fan if the passive ventilation is set up right, and the attic floor is properly air sealed and insulated. Hope this helps! Andy

That response is the best you will get! I have replaced plywood with black mold because of improper ventilation! Also you can’t have to many ridge vent or ventilation for hot air to go because it will work in reverse and not have enough to bring cold air from soffit to ridge vents! I only recommend having a longer ridge vent than to add dormer vents or anything else! If so you will be to know the proper length around your home to have to proper ventilation.

Haha, being "stuck" in roof spaces, ie attics is what I've found I'm best at doing. Andy

I worked in my attics (3 of them) recently, remove old insulation, clean, then put on new insulation, prepare some areas as storage area, cover all large openings with hardware cloth (to prevent animals to crawl in which was my ORIGINAL problem). Believe me, the more I work in these attics, the more I love the work !!! It is so quiet, I am just by myself doing what I feel right to do. All is done now, and I really miss working in my attics.

@@1942nn I don't think that any of our employees would call our work "easy." However, we all love knowing that the work we do will effectively last for as long as the house is standing. And there are very few things that you can fix, or in our case make houses dramatically more energy efficient and comfortable, that are permanent. Andy

He is solving a problem, also he is making a nice living for himself and his family

I hear ya, but honestly, he up there making bank, I'm sure!

Hi Steve, adding ventilation should not have caused mold to grow, unless possibly you live in a tropical environment and previously had been running a dehumidifier in that space? Andy

Hi Robert, Unless you live in a dry climate like Colorado or the Southwest, we always recommend removing whole house fans. From a thermal efficiency standpoint they are lousy in humid summers. That said we build insulated boxes with foam board lids for our customers who insist on having them. In Pittsburgh they're useful for about 3 weeks in the early fall and maybe a few weeks in June. The rest of the time you're going to need to use your AC to remove humidity from the air in order to feel comfortable, so you want that thing sealed as tight as possible. We use RMR mold killer. It is high test stuff let me tell you, you will need a full face respirator and you will not want to get it on you. Also, if you do not seal the air leaks in the rest of your attic floor, and if your roof/ attic is not properly ventilated with a balanced amount of intake and exhaust ventilation, that mold will 100% be coming back. Check out the link to our attic mold page to see how we tackle this: www.insulwise.com/pittsburgh-attic-mold-specialists/ How we air seal attics: www.insulwise.com/insulation/air-sealing-insulwise-pittsburgh/ Hope this helps! Andy

When a house is aligned in an East / West configuration, gable vents (assuming they are the larger kind and not the smaller kind) can do a terrific job ventilating attics because they are able to capture the natural Westward breeze that happens. You won't read about this much, but I have witnessed the effectiveness of gable vents many times. If your home does not have an East / West configuration, I would consider installing slant back vents for intake vents about 1-2 feet up from the gutter. The best option would be to have undershingle intake vents installed, but these are generally only done during a roof replacement. However, the number one thing that you want to do have get your attic air sealed. If you can do this you will dramatically limit the amount of water vapor escaping upward into your attic when it is colder out, and thus reduce the risk of a mold issue (assuming you live in a colder climate). Hope this helped! Andy

You're going to want to get that addressed properly. Most mold remediation companies can only kill the mold in the attic. Very few of them from what we've seen in Pittsburgh understand how moisture gets into attic spaces (it can come from the roof and ALSO the house via Stack Effect in the winter). Andy

Hi there, I am greatly sorry to hear about the passing of your husband. Unfortunately I'm not familiar with the Erie area. The type of solution that Insulwise offers seems to be very unique for this space. What I would recommend doing is hiring an insulation company that focuses on air sealing to come up and air seal your attic floor, make sure that your bathroom fans are venting out of the house properly, and also assess your roof ventilation for any deficiencies. We add additional roof vents all the time (these help attics to dissipate heat in the summer, but more importantly they help excess moisture to escape). Once all the prep work of the roof and attic floor has been done, I would then have the underside of the roof treated by a mold remediation company. We have learned and seen numerous times that if the moisture source in the attic is not addressed, that the mold will more than likely come back. Hope this helps you! Andy

Yeah, I wouldn't recommend attempting to dehumidify your unconditioned and vented attic, which would require dehumidifying the local atmosphere around your home ; ). Condensation almost always forms first on the northern sides of the roof, and typically lower down. That is the area that receives the least amount of sunlight / solar radiative heating during our winter days, so it has the most difficulty warming up and drying out. You first need to make sure that all of your soffit / intake vents are unblocked. Having more functioning exhaust ventilation up high on your roof than intake ventilation down low can "depressurize" your attic...this in effect can create an upward draft in your home that pulls warm moist air upward into your attic through the air leaks in your attic floor. If your intake and exhaust ventilation are balanced, or even better, if you have a bit more intake than exhaust, this is issue is far less likely to happen. The exhaust vents simply draw from the intake vents lower down on the roof. After getting your ventilation figured out you then need to deal with the issue of where the moisture is coming from. If your roof is in good shape, than the moisture is likely coming from inside your home by virtue of Stack Effect causing warm, moist air inside your home to rise and escape upward through air leaks in your attic floor and into your attic. That water vapor then condenses on the underside of your roof sheathing when its' temperature falls below the dewpoint temperature. You need to get these air leaks sealed as they are more than likely contributing to your condensation issue. You also need to make sure that all of your bathroom fans, clothes driers, etc are venting to the outside. Another contributing factor could be a humidifier on your furnace. For the time being turn it off...and I'll bet you'll see a big difference in condensation build up. Where do you think A LOT of that water eventually winds up? You guessed it...your attic. Check out our page here to see what Air Sealing is: www.insulwise.com/insulation/air-sealing-insulwise-pittsburgh/ So, get your ventilation figured out (maximize your intake ventilation), get your attic floor air sealed (either yourself or hire a contractor who understands this stuff), and dial down your humidifier. Once your attic floor has been air sealed, your home will naturally lose MUCH less humidity...so you won't need the humidifier nearly as much. These measures will likely staunch your attic condensation issues. If you have other questions hit me up. Lastly, this is our Attic Mold page. Lots of good pics. www.insulwise.com/pittsburgh-attic-mold-specialists/ Hope this helps! Andy

Yes you absolutely want gable vents on both ends so that the westward breeze can push through your attic, but you ALSO need to make sure that your bathroom fans are vented out through the roof and that your attic floor is air sealed. The first thing to do is staunch the flow of moisture getting into your attic in the first place.

Hi William, I appreciate your comments. Couple of things. 1) Having painted houses for several years I am well experienced with dry rot. What you're seeing on the rafters isn't it. It is absolutely mold growth. There is also another after video we shot where you can see that the underside of the roof looks dramatically different, basically it looks as though it were new ( ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-u_Yu0gv_Hsk.html ) . A dry rotted surface would not react that way. 2) Once the mold has been killed, adequate ventilation has been determined present or added, and the source of moisture eliminated, the wood will not continue to rot as microbes / fungus cannot grow on it due to lack of moisture 3) I am not sure what you mean by ceiling boards. The ceiling below this attic was built using drywall and has several layers of latex paint on it. Although not a perfect vapor barrier, a surface like this functions pretty well as one. After the penetrations / air leaks in the attic floor are sealed with foam the amount of moisture that can move upward from the home and into the attic space is sharply reduced. We often test this in homes using a blower door and separate monometer to conduct a zone pressure test to confirm that we have effectively separated the attic from the living space below. Lastly, we have performed this solution hundreds of times in homes in our area over the years with just a handful of callbacks. And I know with certainty that with mold if you do not fix the moisture issue, it will almost always come back. Thanks! Andy

Great stuff will work just fine, it's actually what we prefer relative to the other brands. We seal around romex wires, junction boxes, etc. You do not want to inject it into a junction box though or risk putting it into direct contact with live wire junctions. It should only be used for sealing the outside of electrical boxes. It'll withstand the heat of hot attics just fine, what will break it down is UV light, which it should not be exposed to inside an attic. Hope this helps! Andy

If the mold is showing up in the knee wall attic spaces than getting ventilation to that space would definitely help. However, you also want to get that space air sealed from the home as best you can, and definitely make sure any bathroom fans venting into that space are vented to the outside. Our order of operation for attic mold is 1) shut down the moisture source 2) properly ventilate the space 3) kill the mold. Hope this helps! Andy

Hi there, thanks for the compliment. So yes, you NEED to have that HVAC system checked out. You've got some things going on there that definitely NEED to be resolved. 1) Make absolutely sure that the roof leaks are fixed. Active leaks will leave staining on the drywall (if they are leaking badly enough). 2) Get your HVAC system checked out. I'm not sure if the HVAC is located in a conditioned space (room is heated and cooled) or an unfinished space (area is not heated and cooled, like a true attic or garage space). If it's in an unconditioned space, it should absolutely NOT be pulling in return air from that space, so there should be no holes in the return. If the closet is in a conditioned space, the hole may not be a bad thing, but it is still suspect. Either way, it should be before the filter, not after it. Any air entering the return NEEDS to be getting filtered. 3) Without removing the drywall, there is likely no way to tell if there is mold above it. 4) It's ok to finish attics so that they are conditioned spaces, they just need to be properly conditioned and insulated. 5) The chimney should be inspected as well, but you can also test it from below to make sure that it is drafting. Hope this helps! Andy

Thanks so much for the answer . Yeah I mean, the attic and the room the furnace and the hole is in have vents pushing hot and cold air in from the heating and cooling system . But the humidity gets very high and the wood is black ontop and the insulation is open next to that hole . And our roof leak was supposedly fixed and then leaked again and the paint fell of twice over the course of a year and it also left a stain. They never removed the drywall on the ceiling , just painted over it and sealed the outside I was looking into hvac cleaning and see evaporator could shouod be cleaned etc, we’ve never done that , zero maintenance . Tbh the rest of the inhabitants of the house feel there is no need to do anything so it creates an incredibly frustrating scenario, especially as I have suffered health issues for years and been borderline begging them for years but they don’t want to spend money

I also thought about the fact the furnace is right below the bare roof and so as it heats up and it’s in the room that can be 80 degrees while the outside can be 20 or less in the winter and vice versa In the summer , this can be creating condensation since it’s not isolating the roof with insulation . It’s just open, as if the roof youre in in this video is sealed but the whole right side is exposed to below and the rest of the house while there is no insulation stopping temperature changes going into that section of the roof

@@heythere6983 The furnace being in that room and close to the roof would actually help to prevent condensation forming on the underside of the roof. It is adding heat to that area, which would help to dry out the roof. The worst condensation and mold problems often form in well insulated attics. This occurs because there is little heat from the house escaping to the attic, which would help to dry the roof. We don't think that I have once ever seen a mold problem in a poorly insulated, or uninsulated attic. You might see some melt patches on the roof when it snows and possibly ice damming, but it sounds like those are the least of your issues. Andy

Oh interesting thanks . I had thought the difference of heat from the inside to the outside would cause the condensation issue

Hi there, If you have a 3rd floor conditioned space, that it will likely require some special considerations (at least if it's constructed similarly to the way 3 story homes are constructed in Pittsburgh). If the third floor has knee walls (short vertical walls about 4ft high), than you will have small attic spaces behind those knee walls. These spaces need special attention. The first order of business is making sure that bath fan is vented to the outside properly. Then you need to decide how you're going to insulate that space. Specifically, you need to decide if you're going to make those small attic spaces conditioned, or unconditioned spaces. We make them unconditioned spaces. This means that we air seal and insulate the floors of the attic space, the back sides of the knee walls, then insulate the sloped ceiling sections and finally the upper main attic. The knee wall attic spaces and upper main attics then need to both be vented with roof vents to allow any potential moisture build-up to dissipate to the outside. If you don't vent them, any moisture that finds its way into those spaces will likely lead to mold growth. Here is a link to how we deal with 3 story and Cape Cod style homes. They have the same effective upper floor construction: Three story home www.insulwise.com/choose-your-house/3-story-home/ Cape Cod style home www.insulwise.com/choose-your-house/cape-cod-home/ We are not fans of insulating the undersides of roofs (with sloped ceilings and cathedrals we recognize that it's unavoidable). We don't like this practice because I can find roof leaks (usually small) in about 80% of the attics that I work in (dry rotted rubber plumbing stack boots, nail pops in shingles, flashing failures around chimneys, etc). I realize that it's becoming popular to spray foam the undersides of roofs, but we also feel this is long term foolish (too many things can go wrong -- foam can delaminate from wood, water can be trapped against roof if there is a leak, or if you've used open cell foam, the foam can be damaged the next time you need your roof re-shingled, etc). As where if you make the knee wall spaces unconditioned, ie insulate the back sides of the knee walls and the knee wall floors, and then install roof of soffit vents, those spaces will more tolerate more "stuff happening" with your roof. Our approach offers a sort of built-in redundancy if you will. So to your original question. If it were me I'd remove the insulation from the underside of the roof deck (you will not have any type of effective air barrier there anyways, so why have your insulation layer there?), air seal the knee wall spaces, treat and eliminate the mold, and then insulate the floor of the knee wall attic spaces and back side of the knee walls, slopes, and upper attic. Hope this helped! Andy

Hi Suraj glad to help! Andy

Hi Ray sorry the late response. I'm not sure that I understand the specific areas that you're referring to. If you eliminated the plumbing leak and that area has been allowed to dry out, whatever mold was growing there will no longer be able to grow. For an added measure any off the shelf "mold killing" solution you'd find at one of the big box stores should wipe out the mold that has been growing there if you can spray it real good. Hope this helps! Andy

@@insulwiseenergycomfortsolu3293 I did all the above, nothing seems to be growing anymore. What I was concerned about is where the floor wood meets the vertical part, the cross part. I can't access the wood, even tried to stab a wet thin cloth between the wood, of course I couldn't access it since they lie on top of each other. So I soaked the edges and hopefully prevent any mold.

Hi there, we generally just use off the shelf Great Stuff from the big box stores. Lots of guys in this field believe you need the fancy expensive foam guns and larger cans, but in reality they get heavy using them for hours, the guns constantly need cleaned, they can break and get accidentally left behind in attics, and there are lots of small, tight areas where we can get a cheapo can of great stuff into, but could not access with the larger foam guns. Andy

It depends. If your attic insulation does not go over your soffit vents, that you probably don't need baffles. However, in all of the attics that we insulate we blow in cellulose insulation until we reach an R-Value of R-49, which is about 15" inches in depth. So we have to install baffles every time where there are soffit vents present, otherwise the cellulose insulation would cover and block the soffit vents. Hope this helps! Andy

Hi Elsa, great question there. That's really how you need to be thinking about issues like mold and condensation...ie, where is the moisture coming from and where can it interact with a surface that is at dewpoint temperature. I have gone into homes where people have shown me small areas of mold that keep coming back on their bedroom ceilings, etc. It seemed very strange. But when I went up into their attic the problem immediately revealed itself. There was no insulation on the areas of the ceiling where the mold kept growing...ie, where water vapor kept condensing. So to answer your question, if the attic floor is properly insulated the ceilings below will never hit dewpoint temperature in most situations. The outliers tend to be bathroom ceilings where there is no bathroom fan that is removing the steamy air from the bathroom and the room is getting continually inundated with moisture. In those situations you can get mold growth on walls and ceilings regardless of how well they are insulated. Hope this helps! Andy

@@insulwiseenergycomfortsolu3293 Thank you for your clarification Andy, that's very helpful!

Ok, if you live in a cold climate what you've just described to me is mold's "dream situation." There is plenty of heat, moisture, and no effective way to dry via outside ventilation. Your ceiling is effectively a screen door, although I have no doubt that from the underside it is beautiful. I have attempted to "fix" several log cabin style homes. They are always quaint and beautiful, but a building scientist's nightmare. If you plywood over the ceiling for storage it will not stop the air leaks. The air and moisture from the home will largely get trapped beneath it, and then mold will begin growing on the underside of the plywood and gradually rot it. This will also allow for the possibility of showering the inside of your home with a steady supply of mold spores down the road (as the spores fall down through the cracks in your ceiling). You need to do 2 things: 1) Completely seal your attic floor from your home below. With what you've described, the best way to accomplish this would be to have a spray foam company come out and spray at least 1" inch of closed cell foam over the entire attic floor. That will provide both an air and more importantly, vapor barrier. You can then insulate over top of that foam and install a storage pad. 2) Find a way to effectively ventilate your attic be installing vents in the roof or a few big gable vents. You always need to provide a way for moisture to escape the top of a structure (unless you are making the air and thermal barrier at the top of the structure, which I'll mention next). OR, You could have a spray foam company come out and use closed cell foam (this is important because only closed cell foam can create an air AND vapor barrier. The more common open cell foam CANNOT give you a vapor barrier, regardless of how thick it is sprayed on, and establishing an effective vapor barrier is critical) to insulate the underside of your roof. This is called a "hot roof" solution. About 3-4" of closed cell foam expertly applied to the underside of your roof would likely create a very nice solution for you. Best of luck! Andy

@@insulwiseenergycomfortsolu3293 Thanks for your Help Andy I’ll have to figure out what to.. I do want to put some gable vents in or maybe windows to also bring some natural light in as well.. I shut down the humidifier and it looks a lot drier up there.. If I have the spray foam on ceiling from the attic before batting insulation and plywood attic floor would that work?

@@fanman1981 Hi there, yes that should work pretty well. But you'll need to use closed cell foam because it will create a vapor barrier as well as a vapor barrier, about 1-2" inches will do nicely. You'll still need to get that attic ventilated though. Sh*t happens in houses my friend, especially with moisture. You'll want a good plan B in the case that it does, and some decent attic vents will help you a lot there. Andy

After we air seal the attic floor and make sure that the attic is ventilated properly, we then spray a mold killing agent onto the underside of the roof deck, killing all of the mold that is present. There is another short video on our page where you can see me doing that, and then another video showing what the roof deck looks like after. Hope this helps! Andy

The moldy wood either needs to be removed and replaced, or sanded down. Please do some research on proper mold remediation. People can get very, very sick from mold... one being me! You cannot solve a mold problem simply by spraying chemicals or paint over mold. Mold has roots so when mold grows on a porous surface like wood, there is no way possible to remove the entire source of mold. Not to mention, even if you kill some of the mold, dead mold is dangerous as well! And lastly, if the mold is a mycotoxin producing mold, spraying a chemical on the mold is going to cause the mold to go into defense mode and release additional dangerous mycotoxins into the environment. I beg of you to please do some research on mold illness and proper mold remediation. Mold can make people deathly ill, and can in fact kill people, as well at pets! I also want to mention those air gaps are probably causing mold to grow in the walls of the home. I say this because that is what happened to my house.

We've never scrubbed the mold off, but some people believe that you need to. You can see in our video that once we're done, it looks like new plywood, it's not furry or anything. Additionally, if you've prepped the attic properly in terms of air sealing the air leaks in the attic floor, making sure the roof isn't leaking, and making sure the roof is properly ventilated, it should be extremely difficult for mold to start growing again. Hope this helps! Andy

@@insulwiseenergycomfortsolu3293 Thanks Andy, do you think I need to go with RMR-86 or is the Vinegar or Borax going to do it?

@@struswell1 We use the RMR and it's legit, but extremely powerful. You will need a full face respirator and rubber / vinyl clothing that it can't easily penetrate (unless you are reaaaally good at avoiding the drips). Concrobium is another good product. A lot of stuff out there will kill it, but you may still see the stains, and they can appear active and still growing even though they're dead. What RMR also does a great job of doing is eliminating the mold stain itself. I'd try the lighter stuff first and see if it works for you. Andy

@@insulwiseenergycomfortsolu3293 Thanks! I hope you get great carma from helping so many people!!

Hi Nicholas, great observation. We assess every attic that we work in for ventilation requirements, the standard being 1 sq ft of ventilation for every 300 sq ft of attic, then divided between intake and exhaust ventilation. In this case the home did not have any type of overhang, it had a mansard roof on it (therefore no possibility of installing soffit vents). In those cases we install slant back vents for intake to balance out the draw from the ridge vents that are exhausting. We would LOVE to see more roofers in our area doing proper ventilation assessments on roofs while selling jobs and installing under shingle intake vents along with the always installed ridge vent. Thanks! Andy

Generally we do not remove the insulation, and for several reasons. If this roof is not leaking, the attic has been well ventilated, and we have effectively air sealed the attic, than very little moisture will continue to get into the attic. Without moisture and damp conditions, mold cannot grow (especially once we have killed it!). When it comes to the insulation itself, mold cannot grow on fiberglass or rock wool because they are inorganic fibers. Mold simply can't eat that stuff. Mold can grow on the craft paper backing, but again without moisture the mold cannot grow. Additionally, the vast majority of cellulose insulation (what we use at Insulwise) manufactured since the 80's comes "infused" with strong and effective mold inhibitors such as boric acid and ammonium sulfate --- both of which are non-toxic and also act as highly effective fire retardants. The vast majority of the time we also blow a new, fresh layer of cellulose insulation over top of whatever insulation is already there. If there are any dormant mold spores they become encapsulated or "entombed" at that point. If the homeowner felt strongly about us removing the original insulation we would, but in most cases we feel that adds a lot of additional cost to the job, without offering much of a net improvement in safety. Thanks! Andy

@@insulwiseenergycomfortsolu3293 Got it. Thank you so much for sharing all the great knowledge Andy!!! It's very hard to find experienced people like you nowadays.

Hi Robert, thanks for the compliment! We do not prime the wood afterward. I have seen attics where that had been done, and mold still regrew mold on top of the primer (or whatever they sprayed onto it). Our take is that if you kill the existing mold, and more importantly --- eliminate the moisture source, that you've effectively solved the problem. There are a number of solutions out there that will reliably kill mold, so we don't offer recommendations. The main thing is getting the floor of the attic completely air sealed (eliminates air leakage from the house that deposits water vapor into the attic), and making sure you don't have any roofing problems or ventilation imbalances that could be adding to the mix. Thanks! Andy

Hi Robert, we do not prime the wood no. I have seen several attics that had already been treated for mold in the past, and had then been primed -- with new mold growing right on top of that primer. If that primer, paint, etc is applied in an area that is good place for mold growth, eventually the mold will start growing again. In the right cirumustances, mold will eventually eat just about anything that is organically based. Once we eliminate the moisture source and kill the existing mold, the problem is solved in most cases.

We are located in Pittsburgh. I don't think my guys would be especially pleased if I scheduled them a job in Wisconsin ; ). If you can't find a company that can handle all of this problem, than I'd hire a good, building science based insulation company to first air seal your attic and do what's necessary to make sure it is effectively ventilated. I would then hire a mold remediation company to take care of the mold, then likely re-insulate once that has been done. Andy

@@insulwiseenergycomfortsolu3293 i totally understand, I will do that thank you very much for replying my comment sir have a great day

Did you take care of it? I also have this in my attic

@@eirod yes I did I hired a company called DJK environment, removed re-insulated cost 6,500 dollars

@@mixtecop what about your ceiling drywall? Was it affected as well? Removed or treated? I only ask because Im starting to see it going through my ceiling bathrooms.. so i know it's going to be pricey. Lol did you get quotes from multiple companies or no??

Dear Hfsdhjf, according to who? Mold is a fungus, and where it exists and is growing on the surface of wood it can absolutely be killed with many of the effective mold killing agents on the market. Furthermore, you can scrub it, sand it, and then kill it with a mold killing agent all that you want --- but if you do not address the underlying conditions that allowed it's growth in the first place, namely high levels of moisture and poor ventilation, then that mold is highly likely to grow right back. We have been called out to address mold growth in numerous attics where mold has already been treated by another company, but then came back. Often there's a white primer or paint on the underside of the roof --- with black, round mold colonies growing right on top of it. Our view of mold is that it is a symptom of a moisture problem. If you remove the moisture, then mold cannot grow. Hope this helps, Andy

The does not need to come out. The only parts of fiberglass insulation that mold can grow on are the kraft paper facing. The rest of it is inorganic, so mold cannot "eat" it. Once the attic floor has been air sealed, the mold has been killed, your attic is properly ventilated, and you are sure that your roof does not have any leaks, the mold should not come back. Andy

@@insulwiseenergycomfortsolu3293 I wish i can hire you to do the work in my attic. I love it when people know whta there talking about! I call 3 differnet companies and I get 3 different answers! so fustrating

@@samvicenzo5340 It's extremely difficult for home owners to get high expertise in this area. 3 contractors could easily have 3 different opinions. Two things. When you can, look to hire a company that is building science based, where the owner is a trained BPI Energy Auditor, that kind of thing. That will at least mean they've been taught how to think about solving these types of problems. The other best practice for the home owner is to ask a TON of questions. Do Not assume your contractor understands these things just because he recommends a scope of work, ask him really explain WHY it will work. IF he starts getting defensive, than you know you've got the wrong guy. Also, anyone who says something like, "look I've been doing this for XYZ years, just trust me," most often needs shown the door. Your retort should always be, "oh you've been doing this for that long? Than you should be able to easily explain why this will work, right?" Andy

We treat the mold immediately after we seal the air leaks in the attic floor, typically same day. Andy

Hi there Georgia, Yes is totally normal to see nails coming through the underside of the roof. Those are from the roofing nails that hold the shingles in place. They can sometimes allow small leaks if the heads of the roofing nails pop through the face of the shingles, but these are usually small. If the attic is properly vented, and if the home isn't pumping significant moisture into the attic via wintertime Stack Effect, these types of "leaks" will typically dry on their own without causing any serious damage. Andy

The nails holding the shingles onto the roof are what's sticking through. The nail head should be covered by the next row of shingles. Therefore, there shouldn't be any water able to get to the nail head to leak into the attic through the nail hole, because they're covered.

Hi Scott, thanks! That can be a weird thing to see and I think I know exactly what you're looking at. If you have mold / mildew growing on just one part of the ceiling on the inside, a common cause of that will often be that that is an area of missing insulation in your attic. The missing insulation causes that to be a cold spot on the ceiling, making it an effective "can of beer in the summertime" kind of thing. The water vapor in the house is condensing on that area of the ceiling, and from there you get mold growth. The fix is to inspect your attic and make sure that it is evenly insulated across the whole surface area. Sometimes people will go up to an attic to do some electric / plumbing work, move the insulation aside, forget to put it back, and from there you can get an area of mold growing on the ceiling. That would be my first guess anyway. Hope this helps! Andy

If you're not in the Pittsburgh area, your best play is contacting a few local mold remediation companies and having them come out and have a look. It could be affecting the health of your family, and it's something that you want to have examined as quickly as you can. Hope this helps! Andy

Unfortunately yes. I would say the vast majority of roofs that we work beneath have small leaks somewhere. Typically it's a piece of roof, chimney, or skylight flashing that has failed for one reason or another, the head(s) of roofing nails that have popped through the face of shingles (extremely common), older / degraded shingles with spiderweb cracks in the face of the shingles (that's what they look like when you examine them closely) that allow water to seep through them rather than shedding it, areas where wind driven rain gets blown in on occasion, dry-rotted and cracked rubber seals that go around your plumbing pipe penetrations (extremely common), etc. The bottom line is that many roofs leak somewhere, but often not that much at a time. If the attic is well ventilated, or poorly insulated, it's often not that much of a problem because the wet area simply dries out once the sun comes back out. But if either or both of those conditions are not happening, you'll have a perfect set up for mold growth. It's always best practice to repair the roof leak as soon as you know that you have one, regardless of its size. Andy

In Pittsburgh from the mid 1960's through the late 1970's there were a lot of homes that were built without any type of overhang. The roof ends directly on top of the exterior walls, and the gutter sits right there too. With these types of homes soffit vents can be installed, but it is a major renovation that involves building onto and extending the roof. A customer of mine was recently quoted $20,000 for doing this. Another option could be installing "smart vents" or undershingle vents about a foot up from the gutter, but this can really only be done when the entire roof is replaced because (unless you want to hire a roofer to cut into your existing shingles, but I'm not sure how challenging a retrofit that is). These types of homes were most often built with gable vents, which we at Insulwise believe to often be extremely effective (when these homes are alligned in an East / West orientation, you'll often feel a breeze blowing right through the attic). Gable vents allow wind to naturally push air directly through the attic, without really depressurizing it. When homes that were built without soffit vents or overhangs have ridge vents installed on them, that's where we seem to see a lot of mold issues. The "intake" for these ridge vents effectively becomes the house itself, especially during the winter months when Stack Effect within the house (warm air becoming buoyant and wanting to rise upward) is already happening. Andy

Hi Chris, soffit vents, or any type of intake ventilation would certainly be helpful here. This home however had a type of roof that wouldn't allow for that. There was literally zero overhang. Also, from our standpoint concerning mold issues, the first and most important thing to do is eliminate the moisture source. You may or may not be able to "ventilate away" a mold issue. But if you eliminate the moisture, or drive down the amount getting to the space dramatically -- you will make it impossible for the mold to continue to grow.

@@insulwiseenergycomfortsolu3293 Makes sense Andy. Where did the bathroom exhausts vent?

All bathroom vents were vented to the outside through the roof. It’s the first thing that we look for.

Hi Sylvain, sorry for the late response, but I'm not sure of the application? Do you mean that contractors put plastic in the attic space? Or in your home below? Andy

If you're unsure of what is going on and do not live in the Pittsburgh area, you should consult a mold remediation company that hopefully understands basic building science principles. Andy

Hi guys, I am sorry to hear that. Mold can absolutely be a serious thing. Unfortunately we don't do any real work with mold in basements. I would do a google search for basement mold and look for the highest rated remediation companies in your area. That said, in looking at solutions, you absolutely will want to contract with someone who understands that among the first orders of business will be understanding the source of, and then mitigating the moisture problem. IMO mold is first and foremost a moisture problem. Remove the excess moisture, and mold cannot grow. Anyone can kill the mold that's present, that's actually the easy part. Best of luck! Andy

The air sealing work that we perform in the attic in combination with the paint on the underside of the ceiling forms a fairly effective, but not perfect vapor barrier. The roof ventilation measures that we often need to install are designed to allow any moisture that makes it into the attic space an easy way to get to the outside. Homes here are not constructed with intentional vapor barriers on the attic floors or the ceilings inside the home. Andy

@@insulwiseenergycomfortsolu3293 thanks Andy. Im restoring and older home, simple farm style. Ive cleaned the attic of old insulation, rock-wool matress stuffing, cardboard, fibreglass etc down to the deck. Ive been told older homes need to breath, but also people have said I need a vapour barrier. There is also probably 30 layers of paint on interior cladding.

@@StanTheMan-us3tp Ok I understand, that was probably a lot of work! Short of spraying 2" of closed cell foam onto the floor of the entire attic, you're not going to be able to put down any sort of effective vapor barrier. That would be great, but highly expensive and also unnecessary. You want to make sure to air seal your attic floor by sealing shut the air leaks and vent any bathroom fans out through the roof. These two things are critical. After that make sure that your roof is watertight and properly ventilated (you will need both intake AND exhaust ventilation, and probably more of it than you'd think). Here is a link to our attic air sealing page so that you know what we're talking about. www.insulwise.com/insulation/air-sealing-insulwise-pittsburgh/ At this point you've done two things. You've sharply reduced the amount of moisture that can get into your attic in the first place, and you've provided an effective pathway for it to get out (if some does get in) in the second place. Your attic floor is now ready to be re-insulated. For a variety of reasons we are big advocates of using blown in cellulose insulation, probably blown in to about 15" of depth for an R-49 insulation rating. Hope this helps! Andy

@@insulwiseenergycomfortsolu3293 thanks for taking the time to write back, informative and much appreciated. Cheers

@@insulwiseenergycomfortsolu3293 It's necessary dependent on your area/building code. I live in Ontario, Canada. Our builds will not pass without a proper seal between the attic/exterior walls(We use 6mm Vapour Barrier) Generally spraying at least 2' of spray foam, with R-50 of cellulose on top is the only fix for most retro's here, unless we drop the ceiling. Very interesting seeing how different insulation can be in warmer climates none the less! From one family business to the next, I commend any insulator that's reputable. The industry is filled with total wanks

Mold shouldn't smell anything like the "piney or skunky" smells associated with weed. Mold smells musty like a damp basement. Andy

@@insulwiseenergycomfortsolu3293 my house has a piney weed smell and it just got cold outside nobody smokes in my house do u know what can cause that

@@valdez2799 I do not. If your home has carpets I would recommend them getting cleaned and if it has ducts I would recommend also having them cleaned. I'd also ask the people that come in to perform the work what they think it could be. Both of those solutions are relatively low cost and will leave your home cleaner and better off even if the piney weed smell isn't resolved. Andy

Not sure what sticky battross is, but when doing the work we absolutely wear masks. However during the demonstration video is nearly impossible to talk with one on and be understood which is why I'm not wearing one here. Andy

@@insulwiseenergycomfortsolu3293 It's a type od deadly mold.

@@HBO1984. Well, I couldn't find anything online for battrosia or sticky battrosia, and we're around this stuff all the time. It doesn't bother myself or my team at all, and trust I'm still here. When we're working in attics and not shooting videos we're always wearing respirators. And for anyone considering working in an attic I'd recommend wearing an N-95 minimum respirator because there's simply nothing good that you're going to breathe in those spaces. That said, I don't doubt that other people may be much more sensitive to it. The biggest problem with the type of mold that's growing on the underside of that roof is that it is literally eating the roof. We commonly see roofs here that need replaced because they've been so degraded by mold growth. Andy