Mildew Issues in Insulated Walls

[obdormition]

Hi everyone. We are first time chicken owners and built our coop following some plans we found online from the Tangled Nest. We have three hens.

We insulated our coop with foam sheets and styrofoam panels with reflective backings. The walls are layered: wood siding on exterior, then the insulation set into the wood frame, then 1/2-inch reclaimed heat treated plywood on the inside over the frame and insulation. The inside has two coats of non-toxic siloxane waterproofer.

The online plans obviously don't have any ventilation, but the tops of our front and back walls have a 3 inch gap all the way across covered with hardware cloth. We also have two small windows (8x6in) in the coop for a cross breeze.

We had some roof leak issues which we've fixed. We had some resulting mildew/mold on the inner walls, which we cleaned with vinegar. Unfortunately, I took the inner panel off today and we do have mildew on the inner part of the wood where the insulation rests (photo). It's a thin layer and easily comes off with a spray of vinegar.

How do we proceed? Take the walls apart and clean with vinegar, then re-assemble? Scrap the insulation altogether and just have the one layer of 1-inch exterior wall and frame? Is this even something to be concerned about? Feeling really discouraged. We are adding more ventilation as I know that we don't have enough. In central NC. Thank you very much.

 

[rosemarythyme]

I would scrap the insulation entirely. It's unfortunate you put the work and money into installing it, but it really isn't necessary in most cases and only serves to provide hiding spots for rodents if any get in.

Assuming the roof leaking issue was completely fixed, I don't think the mildew/mold will be an issue regardless if you leave the insulation in. But yes you could do with more ventilation, and the hardware cloth covering it should be better attached. I see a few screws that seem to be holding it in place, no fender washers or trim wood, and nothing securing the wire at the top. Although it's fairly unlikely something would push through, it'd be safer if it was attached securely on all sides.

 

[perkolator]

Is that a 3" gap or a 1.5" gap (2x4 on it's side)? To me it definitely looks like it lacks ventilation, especially for the humid climate you're in. The build you linked to looks like it has zero, so I'd guess they have even more mold issues! ....and that's apparently put into a book on chickens that people are buying

I'd likely be hole-sawing soffit holes up along that top edge to add more ventilation, or cut out that plywood baffle thing up there at the top so it's nice and open. Additional windows would also help, you can always add a way to shut them if need be in winter time to lessen the airflow a tad. I'd lean toward removing the insulation, or maybe ventilate your wall cavity so any moisture can escape (make sure you block it from rodents/pests) Most people don't insulate their coops, the chickens don't really need it, not even in really cold areas as long as the coop is designed right.

 

[obdormition]

I would scrap the insulation entirely. It's unfortunate you put the work and money into installing it, but it really isn't necessary in most cases and only serves to provide hiding spots for rodents if any get in.

Assuming the roof leaking issue was completely fixed, I don't think the mildew/mold will be an issue regardless if you leave the insulation in. But yes you could do with more ventilation, and the hardware cloth covering it should be better attached. I see a few screws that seem to be holding it in place, no fender washers or trim wood, and nothing securing the wire at the top. Although it's fairly unlikely something would push through, it'd be safer if it was attached securely on all sides.

Thank you so much! There is additional hardware cloth on the exterior side that is well secured with lathe screws and poultry staples, we just never took down the stuff on the interior. We started putting it there and then realized how difficult it was going to be to hammer in the staples to the roof We're going to add ventilation ASAP. Do you think we need to take the walls apart to clean the existing mildew/mold?

 

[obdormition]

Is that a 3" gap or a 1.5" gap (2x4 on it's side)? To me it definitely looks like it lacks ventilation, especially for the humid climate you're in. The build you linked to looks like it has zero, so I'd guess they have even more mold issues! ....and that's apparently put into a book on chickens that people are buying

I'd likely be hole-sawing soffit holes up along that top edge to add more ventilation, or cut out that plywood baffle thing up there at the top so it's nice and open. Additional windows would also help, you can always add a way to shut them if need be in winter time to lessen the airflow a tad. I'd lean toward removing the insulation, or maybe ventilate your wall cavity so any moisture can escape (make sure you block it from rodents/pests) Most people don't insulate their coops, the chickens don't really need it, not even in really cold areas as long as the coop is designed right.

We loved the design of the coop, and unfortunately hadn't found this website yet...it's honestly a miracle we thought to add the ventilation we currently have!

Good point about the gaps -- they are truly built to be three inches, but the plywood strip at the top obscures part of it a bit, and you can't see it very well from the pictures I posted, anyways. Here are some older pictures where you can see the gaps better as they go up under the roof. Bonus picture of the rear gap that extends to the sides with our four "pullets"....

We'll take that strip of plywood off. We mostly just had it there so the girls wouldn't peck at the insulation that peeks out, since there is not a top plate covering that part. We're absolutely adding more ventilation. Do you think we need to deep clean the interior part of the walls here where the mildew is, or have we caught it early enough? Thanks a lot!

 

[rosemarythyme]

Thank you so much! There is additional hardware cloth on the exterior side that is well secured with lathe screws and poultry staples, we just never took down the stuff on the interior. We started putting it there and then realized how difficult it was going to be to hammer in the staples to the roof We're going to add ventilation ASAP. Do you think we need to take the walls apart to clean the existing mildew/mold?

Gotcha, as long as the hardware cloth outside is well secured then you're good.

If you plan on leaving the walls sealed with insulation inside, I think you can probably leave it alone, as long as no more moisture gets in the mold shouldn't be an issue as long as it stays sealed inside the wall.

If you plan on unsealing it and removing the insulation, then cleaning it off would be a good idea.

 

[Debbie292d]

Hi everyone. We are first time chicken owners and built our coop following some plans we found online from the Tangled Nest. We have three hens.

We insulated our coop with foam sheets and styrofoam panels with reflective backings. The walls are layered: wood siding on exterior, then the insulation set into the wood frame, then 1/2-inch reclaimed heat treated plywood on the inside over the frame and insulation. The inside has two coats of non-toxic siloxane waterproofer.

The online plans obviously don't have any ventilation, but the tops of our front and back walls have a 3 inch gap all the way across covered with hardware cloth. We also have two small windows (8x6in) in the coop for a cross breeze.

We had some roof leak issues which we've fixed. We had some resulting mildew/mold on the inner walls, which we cleaned with vinegar. Unfortunately, I took the inner panel off today and we do have mildew on the inner part of the wood where the insulation rests (photo). It's a thin layer and easily comes off with a spray of vinegar.

How do we proceed? Take the walls apart and clean with vinegar, then re-assemble? Scrap the insulation altogether and just have the one layer of 1-inch exterior wall and frame? Is this even something to be concerned about? Feeling really discouraged. We are adding more ventilation as I know that we don't have enough. In central NC. Thank you very much.

View attachment 3657617

I saw all the replies, and you got some excellent advice. That's a cute coop, and going to be so much nicer once you have it spiffed up. We're up in WI where avg. daily RH is 81%, and mold starts at 70%, so we have to watch for that in the coop. We put an industrial-type digital exhaust fan in which we set the min/max temp and min/max humidity. That helps a ton. Our coop is insulated, and we take other measures to keep humidity down in there, but I think you've already got it taken care of and are onto having an awesome coop!

 

[marwfb]

I saw all the replies, and you got some excellent advice. That's a cute coop, and going to be so much nicer once you have it spiffed up. We're up in WI where avg. daily RH is 81%, and mold starts at 70%, so we have to watch for that in the coop. We put an industrial-type digital exhaust fan in which we set the min/max temp and min/max humidity. That helps a ton. Our coop is insulated, and we take other measures to keep humidity down in there, but I think you've already got it taken care of and are onto having an awesome coop!

We live in WI also and did not realize the humidity/mold issue until your post. I came looking because I just saw a little mold in our coop up on the top plate of the wall holding the roof. I think we have plenty of ventilation. Can you go more into detail on what products you have to control and monitor the humidity in the coop? What levels do you turn on and off the fan? Do you use it in the summer also? Doesn't the fan just pull in more 80% humidity air? I have a covered waterer in the coop but they spill a bit so maybe I'll put that in the run. I just brought power out to the coop for a heated waterer and at the same time added a heater that I figured I'll turn on only if the temps are in danger of getting below -15. But maybe I can use this heater to dry out the air? It's a small coop with only 3 birds. I think it's about a 4x8x4tall coop.

 

[Debbie292d]

We live in WI also and did not realize the humidity/mold issue until your post. I came looking because I just saw a little mold in our coop up on the top plate of the wall holding the roof. I think we have plenty of ventilation. Can you go more into detail on what products you have to control and monitor the humidity in the coop? What levels do you turn on and off the fan? Do you use it in the summer also? Doesn't the fan just pull in more 80% humidity air? I have a covered waterer in the coop but they spill a bit so maybe I'll put that in the run. I just brought power out to the coop for a heated waterer and at the same time added a heater that I figured I'll turn on only if the temps are in danger of getting below -15. But maybe I can use this heater to dry out the air? It's a small coop with only 3 birds. I think it's about a 4x8x4tall coop.

The fan won't come on for the humidity setting unless the coop gets 70 and sometimes we've had to shut it off as it would be counter-productive. It's sort of rare though as the coop with 14 chickens in a 5x12 coop stays relatively dry now.

For in the coop dryness, we use horse bedding pellets. You can get them at any farm store and are about $8 for 40#. We put about 3" and don't do anything for a year. With only 3 chickens, you might need to use a stick and stir them around occasionally. We only remove/replace in the spring. We put the dehydrated poop and sawdust mix around trees, bushes, in the garden, and in the compost.

For water, we use a 5-gallon DYI nipple bucket. Since you have electricity in the coop, so could get one of those 2-gallon heated nipple buckets. We heat our coop to 40F so our bucket doesn't freeze. The nipple buckets don't slop water and the few drips here and there are quickly absorbed by the horse pellets.

The fan we have has a phone app I could check but I have one I like better with a display so hubby can check it too, and it has 3 sensors so we put one in the coop, one outside, and one in the basement. Here's that one.

I'm sure us heating to 40F may help lower humidity a little bit but I know keeping the poop dried out and no open water are the two main things that help.

Oh, and hey, welcome to BYC!!!