Moldy Horror Show in the Attic. Help! HVAC experts, anybody

[diggdugg]

I may be able to help you here schwilly. Being a lifelong roofer I've dealt with lots of ventalation issues. What's happening is your ridge vents are pulling warm, moist air from your box thru your in-line ducting up thru the attic and out thru the ridge vent. Here is why--
1. Hot air rises
2. Ridge vents only work(like they are supposed to) when they have an air source to draw FROM. That is what those soffit vents are there for. Hot air in the attic is removed by fresh air being PULLED thru the soffit vents by the ridge vent.

So, your ridge vents are not only pulling air thru the soffit but also your box, which is introducing warmth and moisture for that mold to thrive!
What you need is a one way flapper valve in your ducting. the forced air from your fan will blow (or pull) the valve open while operating. These are cheap and easy if your using 6" round pipe. Kind of like a dryer vent you would see on an outside wall.
Test: If I read right you are pulling fresh air from the attic to your box and exausting into your house. With the in-line fan OFF get in the attic and close the attic hatch. Fire up a doob and see where the smoke goes. Hope that helps.

 

[schwilly]

Hey diggdugg, thanks for the info from a guy in the field.

I know that I have practically typed up a novel so i don't blame you for missing it but I clarified a few posts up that there is indeed a flapper valve on the ducting. I check it often and have never found it stuck open either.

I think the working theory now is that the attic is just very poorly sealed from the living space. That combined with me keeping it near 80 degrees in here and duct or no duct there is moisture making it up there and condensing on everything.

 

[Phillthy]

it's a really small space, at the peak of the roof it's only 5 feet tall and then slanting down. last year it was mostly empty up there. this year it is stacked with shit. there is well over a thousand pounds of coco, soil, ewc, and dry amendments up there. i don't know if all that moist organic material is contributing or not.

this is exactly why you are having a problem. the soil and shit up there gives off mad humidity and also contains many of the spores that contributed to your problem. attics are normally only exhausted in the summer via a thermostatically controlled fan. it never comes on in the winter and the attic is only 'exhausted' via vents at either end of the house, normally. with nothing up there, or only dry goods stored there, there wouldnt be an issue. with the soil and microbial activity up there, a perfect breeding ground for mold has been created. dark and damp.

i would ditch the shit up there or store it somewhere else and then spray for the mold.

 

[praisehim.]

^^ what he said. get rid of your shit in the attic an clean up. a good harvest isnt worht your health. Mold can cause permanent health issues, that'll ruin your life.

 

[schwilly]

this is exactly why you are having a problem. the soil and shit up there gives off mad humidity and also contains many of the spores that contributed to your problem. attics are normally only exhausted in the summer via a thermostatically controlled fan. it never comes on in the winter and the attic is only 'exhausted' via vents at either end of the house, normally. with nothing up there, or only dry goods stored there, there wouldnt be an issue. with the soil and microbial activity up there, a perfect breeding ground for mold has been created. dark and damp.

i would ditch the shit up there or store it somewhere else and then spray for the mold.

thanks for stopping by phillthy.

I guess I didn't think it would give off too much humidity, everything up there is still sealed in bags. I just like to season every new bag of components for my mix to let anything in them like aphids die off. I know the bags have breathing holes but it still seems like the moisture they give off would be negligible in the grand scheme of things.

All my mixed up soil and recycled soil stays in big totes on ground level. Not that I could get them up there anyways.

I wasn't thinking of the bagged components as spore sources but now that you say it it seems obvious. I bet those things are pumping out spores like crazy going through temp and humidity cycles up there.

This place is old and has no forced ventilation in the attic. Just ridge and soffit vents for year round ventilation.

^^ what he said. get rid of your shit in the attic an clean up. a good harvest isnt worht your health. Mold can cause permanent health issues, that'll ruin your life.

Yea, looks like I got a project coming up. I'm no longer using attic air to cool the box but I'm sure it's still not good to have mold up there.

Like I've said the whole reason I'm in this kind of situation is I moved to a new town to finish my degree, I'm on my own here, no other places to stash anything. I really didn't want bags of shit stacked in my living space. Oh well, only a few more months.

thanks

 

[RM - aquagrower]

Another lifelong roofer here.

I know that you are moving soon, so this is more directed to anyone else who comes accross this.

First thing is to verify that the attic ventilation system is working. I usually do a smoke test. On a day in which the sun is shining on the roof, hold the lit end of a joint (cig,insence,etc.) to a soffit vent. If the smoke is drawn in, then you have intake. The reason to do in when the sun is shining is that roof deck temps (in the full sun) average 2x the ambient (shade) temp.

If you have no intake, then ya got to find the problem. Since the ladder is probably out to reach the soffit vent, hop up onto the roof and look at the ridgevent. If it has shingles nailed on top (shingle over type), verify that it is NOT "Cobra Vent". (Cobra is the cheapest shingle over on the market). Cobra is a roll vent approx 10" wide, and made of "brillow pad type of material". Long story short is that it is junk and just don't work.

If the ridge vent looks good, head into the attic to verify that the rafter/soffit cavity isn't blocked with insolation. If you are blocked with inso, eave baffels need to be installed.

Also, all roof power pans I install have a "H/T1" controller. This is a combo thermastat/humidistat. Therma works in summer to cool the attic space, humid works in winter to control humidity. This is what I would recomend to the OP, after getting the soil and shit out of there.

One more thing to concider is that exhaust (ridge vent, turtle/box/static vents, ect.) don't do anything when covered with snow.

 

[schwilly]

thanks aquagrower.

i have since used weather stripping to seal the attic ceiling hatch really well. i think warm air was getting forced up through there by the positive pressure created in my living space when pumping attic air to the box. also, most of the mold was concentrated in the area around the hatch. i put all the bags of soil, coco, and ewc in big contractor trash bags and tied them shut.

i don't think the ridge vent is cobra vent but there is still obviously really poor ventilation up there. it is shingle over type. soffit vents aren't blocked but i don't think they are the limiting factor. no problem reaching the soffit vents, i can touch them from the ground. this is an old single story shotgun style place. lots of people probably have living rooms about as big as my whole place.

we also have some drier weather here now. combined with me keeping it about ten degrees cooler in my living space and I don't think near as much air from my living space is making it up there. humidity still stays around 60-80% up there but the mold seems to have stopped spreading and just doesn't look as "alive". no more visible condensation on the tips of roofing nails.

i think that maybe with the summer type humidity we were having and no warm sun to drive any convection up there the air was just sitting stagnant. weather conditions this winter just came together in a way to cause mold in a poorly vented attic. i wouldn't be surprised if lots of people around here got some mold as well.