Bleach Bombs for Attic Mold (was Roof Problems in Cold Weather)

[tioga 0630]

I'm reposting and hope Pop or someone else will reply.

I had a roofing contractor--the real deal--come and inspect the crawl-space attic from the inside and out. He says mold is a very big problem and that he'll have to replace a lot of the plywood.

Question: He told me that if I don't want to commit to a December job (which I don't, because there's no sun for the shingles), I can begin to fight the mold by setting off bleach bombs.

HOLY S#@T! Bleach fumes almost killed me in my sleep one night, in SUMMER, when I went wild trying to renew an old linoleum floor. This was with the windows all open and the bedroom I slept in on the second floor!

He says you have to stay out of the house for two days because the fumes are so strong. If these bombs work so well, wouldn't that mean they infiltrate the ceiling drywall of the living quarters (this is a ranch home)? There's loose, not rolled, insulation, which certainly would soak up the bleach too, wouldn't it?

I realize how serious a problem mold is, but does anyone have experience with killing this kind of spider with a shotgun? It seems the cure is at least as bad as the problem.

Thanks.

[Michael Baugh]

I'm not impressed. First plan needs to be to properly ventilate the roof. Mold flourishes at and above 55% humidity. But before removing the plywood, the mold needs to be killed. Centers for Disease Control (CDC) advocates a 1:10 mix of Clorox in water, and that is seen as more effective than straight bleach, because of the water serving as the interface. A bit less than a pint of Clorox in a gallon of solution would be close to their figure.

So, we have a dilute bleach solution needing to be applied to all surfaces, with plenty of contact time. I've known of people to use a garden sprayer for the task. For smaller jobs, a window cleaner sprayer. Not a stream, but a good spritz. Needs to be applied to ALL surfaces, not just the wood.

Not exactly the same as a bleach bomb, though. But certainly more trouble. BTW, your roof needs AT LEAST one square foot of vent opening for every 300 square feet of vented space, or you have no shingles warranty.

I suggest calling theOwens-Corning roofing folks at

1-800-ROOFING with your roof mold question. Might also expect them to discuss ventilation with your mold issue.

[m Ransley]

I never heard of a Bleach Bomb, where do you buy them. You have mold because you are not vented enough or you have serious leaks. Do you see water comming in, do you have proper venting to maintain circulation and near outside temperature. Undervented attics will condense water on roof decks and mold. Is the mold everywhere or localised, as in a leak area or possibly where warm air is rising from below. You can get a garden sprayer and spray the areas with bleach, again I never heard of a Bleach Bomb.

[m Ransley]

Mike , that is interesting what you say about bleach, but I have found the oposite. I have a house in shade and every year use 4-6 gallons of bleach outside on concrete and wood, when I dilute it 50% I need to redo it again, just waisting my time. Bleach is commonly 96-98% water to start with. The Active ingredient being Sodium Hypochlorate. Do you have a link to your statement.

[Speedy Jim]

Forget it. As you noted, the chlorine fumes are a major lung irritant.

I got involved with this over 10 yrs ago. Foolishly spraying the stuff without proper protection or ventilation. And that wasn't even in a tight space like under a roof. I still suffer effects to this day which are not reversible.

Another approach is to use a fogging machine, left unattended. There are biocides today which can be used and are far less toxic than bleach:

Do some GOOGLE searching for mold remediation. Lots of commercial quick buck sites but some good info too.

Jim

[zxcvbob]

It sounds like a horrible idea.

I would fix the ventilation problem that is causing the mold growth, then if there is really a lot of it up there I would spray with a mild fungicide -- maybe something like bordeaux mixture (lime + copper sulfate) -- while wearing a proper respirator.

Bob

[m Ransley]

Zxcv a Bordeaux mix? Isnt copper sulfate poison? When it dries it may enter the house as dust! Bleach dries in a few hours and no smell in

2 days

[Pop]

Try going to

and search for mold

[Pop]

Also,

[Pop]

Try this:

Find a pre-screened contractor for mold containment. From what I'm seeing, this isn't really a diy job.

[zxcvbob]

Copper sulfate is not particularly toxic. But I wouldn't eat the stuff.

Bordeaux might not be the best choice, but I would use some kind of copper or manganese fungicide that will leave a fungus-deterring residue.

The important thing though is to fix the moisture problem.

Bob

[Lar]

:) I realize how serious a problem mold is, but does anyone have :) experience with killing this kind of spider with a shotgun? It seems :) the cure is at least as bad as the problem.

Do you know which mold is a problem? Nmerous types of mold will be found around ANY home. Not sure I would trust the opinion of a "roofer", don't care how long he has been roofing. Find a company that is licensed and will inspect and tell you what types you may have and if any health concerns or present.

Lar. (to e-mail, get rid of the BUGS!!

Dancing dog is back!

[m Ransley]

Start with more venting it is cheap, hard to price or say what type without a photo. But 100$ and up. That might cure everything and the mold will just die and you are done. There are soffit, eave, side and roof vent options. You have ridge vents, but now you need an entry vent to allow the ridge vent to work. The winter temps need to be near outside in the attic or condensation will continue. Warm air infiltration from below may also be a problem .

[tioga0630]

[SNIP GREAT SUGGESTION]

Ho, Y-E-S. I'm mad as H#$l tonight. The bona fide roofing contractor came back today to finish his estimate. He confirmed that my mom was ripped off when the '95 roofer told her the ridge vent was adequate. The new roofer suggests at least six vents (cans) and says that hip roofs are the worst for mold. He made it clear that 1) running a bathroom fan into the attic, 2) having the DWV stacks running into the attic, and 3) telling an old lady that ridge venting was sufficient was the work of a scam artist.

But to make things worse, a second guy I have coming in for an estimate tomorrow finished our appointment-setting by telling me, "Oh, so your house is rotting from the inside out." What a way to make somebody feel great...

[m Ransley]

You mean your vent fan and stacks discharge into the attic? I hope not, but if that is what you are saying there is 95% of the problem. Before you accept a bid find out your roofs venting needs in Cu ft.

[batticdoor]

Here is a related article I wrote - hope it helps.

Got Attic Mold? Lets Talk Energy Conservation! - by Mark D. Tyrol,

- December 2004

It happens to countless homeowners around the end of the year - you make the annual visit to your attic to collect the holiday decorations and what do you find? Spots and blotches covering the bottom of the roof sheathing. Worse yet - it turns out to be attic mold!

What does energy conservation have to do with mold in the attic? Well if you take a step back and consider how the house behaves as system, they are often directly related.

Building science experts have long been using the "house as a system" approach to diagnose the cause and origin of building defects.

For example, ice dams. These are often caused by warm air seeping into the attic which causes the snow and ice on the roof to melt. The water drains to the edge of the roof (which is colder than the rest of the roof because it is an overhang and not warmed by the attic), freezes and creates an ice dam. As this process is repeated daily, the ice dam grows larger. Eventually water is forced under a shingle where it can seep into the house.

Understanding how the house behaves as a system and the various causes and effects is necessary to diagnose most building related problems.

But how about that attic mold? How did it get there?

Mold requires chronic moisture to form and to thrive, so source(s) of moisture must be present. Possibly the moisture came from outdoors. The roof is newer and a quick check of the roof shows no obvious damage or leaks.

Possibly the moisture came from indoors. During the heating season, the interior of the house frequently has high moisture levels, especially bathrooms and kitchens. A quick check shows that all bathroom fans, kitchen vents, etc. are properly ducted completely outdoors and not into the attic. The amount of insulation looks good and the attic is well ventilated.

Don't give up - you are almost there! Remember the house as a system? You know that warm, moist air is in the house, but how is it getting into the attic?

By air leaks! Air leaks are the leading source of energy loss in most houses, and a frequent source of chronic moisture that can cause attic mold. Most homeowners are well aware of air leaks around windows and doors (especially old ones), but many overlook the numerous gaps leading directly into the attic!

Have a look around the attic and you may find large gaps around recessed lights and fans, holes where wires or pipes are installed, even large gaps around the chimney. And don't overlook the whole house fan and especially the folding attic stair - a big, uninsulated hole in your ceiling that is often overlooked!

These gaps can add up to a large hole that allows warm, moist air from the house to flow right into the cold attic. The warm moist air condenses on the cold roof sheathing, creating chronically damp conditions that can lead to attic mold growth. And the energy loss - it can be like leaving a window open all winter long!

Seal these air leaks and you stop a significant moisture source. And just think of all the energy you can save and the cold drafts you can stop!

Mark D. Tyrol is a Professional Engineer specializing in cause and origin of construction defects. He developed several residential energy conservation products including an attic stair cover and a fireplace draftstopper. To learn more visit