Thread: high humidity horse barn

I got called to look at a horse barn with high humidity. There were statements that it was raining in the attic area so the mech. contrctor shows up and puts a louvered intake and exhaust fan at the other end of the building; this seemed to eliminate the moisture in the attic.
The front door gets so much humidity that they have to chip the ice to get out on cold days.
The main riding arena has five of the radiant tube heaters exhausted into the attic; no wonder the rain before power venting.
my customer is wondering why heat bills are so high and why mold is showing up on the unfinished wood in the stables.

Hmmm

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It is a wonder someone has not died! I'll bet anyone that spends much time in there has headaches or other CO poisoning symptoms.
Moisture will likely continue to be an issue if there is uncovered soil even when they fix the venting, though.
Good catch!

Jim
I was called out to review to possibly set this up for litigation as the GC doesn't want to address these issues in entirety. I have explained some things to the owner but sometimes they are hard of understanding and want what they want no matter how unrealistic.
I don't care how much you finish off a barn you will still have higher humidity. There are some who think that installing an air exchanger for 50k will really help this situation but I contend the results will be somewhat disappointing.

The exhausting of the radiant heat system is likely not a big deal only from the sense this is a metal roof and given the construction of a riding stable there will be plenty of air leakage into and out of the building up and out of the building.

However the radiant exhaust should be terminated horizontally out of the gable end(s) of the arena. That is a requirement of the manufacturer.

How many horse are stabled or is it just an arena?

Horse and cattle barns will have higher humidity and its not uncommon in cold weather to see a lot of condensation caused by horses breathing, urine, heat from their bodies, manure, and moisture coming up from dirt floor stalls even if there are rubber matts installed. As well moisture coming up from the dirt floor of the arena.

Are the walls of the stable and arena insulated?

Are you sure those are not air intakes in the attic area. The pictures show the tubes exiting out through the wall of the arena?

Another question; is there a wash bay in the barn?

http://superiorradiant.com/Portals/0...U%20Manual.pdf

Raymond
Thanks for the question.
The visit I made to gather the info so far was just a first visit to get acquainted with the layout and preliminary info.
Good observation as to the radiant heaters; I drove back by this afternoon and took additional pictures and confirmed the exhaust is out the side of the building.
I still think the excessive moisture in the attic is due to the exhausting of the of the heaters. the position of the exhaust would lend itself to the exhaust traveling up to the soffit vents and back into the attic. I agree with your assessment of all of the internal humidity generation. There are a couple of wash bays in the barn and at lease fifty horses so there is a lot of humidity generated by just the horses.
The envelope does have its issues but I see a lot that will be hard to control. I think the big point is unrealistic expectations to some extent.

Hi Mark,

I think you are on the right track, and Raymond provided some good information. Having experience with horses and barns, I concur that the operation itself lends to high humidity. I agree that the key to success (or improvement) is ventilation (air exchange).

Mark,
Side note, a horse can take in 5 gal of water a day and it does eventually come out one way or another. Horse barns are a lot like indoor pools, there is a lot of water being deposited in them and it does not drain out, it evaporates.

If you have fifty horses being exercised daily, they will perspire as well as heavy respiration and cool off period will add quite a bit of moisture to the interior of the barn.

The fix may be as simple as a small exhaust fan on a humidistat at one end of the bay with the intake at the other end.

Mark
Further to your research a few articles of interest.


Horse Barn Ventilation


Barn Heating and Ventilation

Horse Facility Temperature And Humidity **
During Winter Conditions
http://extension.psu.edu/animals/equ...ter-conditions

Raymond I was in the midst of typing this reply and I see you added another post with additional info. I am posting this ahead of reviewing your additional.
i hope this does not confuse anything in this stream.

Steve, Gary, Raymond

Thanks for the replies.

Raymond,
this area is vented with intakes on the north and exhausts on the south. They are louvered and on a humidistat. These are constantly running and really cool the place off. In Iowa, in the winter, it can get pretty chilly and when these fans turn on it can cool off the place pretty rapidly. The heat bills have been high compared to another facility that a friend of my clients owns. This other facility is comparable in size but not in some other aspects. He compares his to that of his friends but does not account for the differences. I think there are some unreal expectations as well as some issues that need to be resolved. As you guys make observations and I think through what you are saying, things become a little clearer and I think I can sum it up for my client.

There are details that need to be changed to make it better but there is also a lot you cannot do. This is a barn, it is the winter, you will not make it like an arena in the summertime.
The Arena is 220x60x16 with a dirt floor.
The stall barn is 76x22x13 with a concrete floor.
There is another area that has two wash bays that is 48x36x10.
This equates to a big area 250k cubic feet

Just a few thoughts:

What is different about the barn that is doing well?
Building materials?
Metal can not absorb water and cannot breath/dry out. = adds to saturation.
I'm sure to conserve heat most of the few windows are closed and the building is like and upside down roasting pan.
Have you measured the RH in the barn? In different areas/heights. Or the AH outside?
Airflow/moisture flow pattern ? Balanced? It is not simply a matter of cfm, it is the way the building is ventilated that may be having an effect on the buildings performance.
Are there particlar areas where the problem is more significant? Do they have anything in common? Are the stalls closed in and dead spots?
All info plotted out on floor plan including construction details.
Is the current ventilation in/out all up high, since heat rises it may be ideal for keeping the barn cool in the summer, but may not be ideal for removing humidity in the winter.
I wonder if smaller exhaust/make up in different areas, with separate humidistat(s) would be more efficient.
Circulation may also be a factor. I would turn on fan and test different areas to determine if the are dead spots.
Is the location of the humidistat having an effect on the performance?

Hi Mark;
You have gotten some good info and comments on this problem. We install pre-engineered steel buildings, no wood trusses, all steel. Condensation is a big problem with metal roofing. We always suggest at least the 3" vinyl faced insulation above the purlins, under the finish roof to prevent that condensation. Our buildings have triple layer gasket seals that go on at the soffit. The peak receives a mastic seal for the ridge pieces. This pretty much eliminates infiltration from the outside. I see a ceiling with a small amount of blown in above. No visible vapor barrier to prevent the moisture in the arena from moving into the attic. The heated moisture in the arena makes the pressure/temperature/vapor gradient to the attic that much more powerful.
Is that an insulated vertical wall assembly? If not, you have lost the battle at the start. The environment inside must be controllable. Seals at the bottom of insulated walls, doors and windows; control of vapor/air movement into the attic. Then you can think of controlling the heat loss with other measures. If you have uncontrollable openings in the building, you can not hope to control the environment.
Don't want to get too long winded.

Originally Posted by Mark Parlee

... this area is vented with intakes on the north and exhausts on the south. They are louvered and on a humidistat. These are constantly running and really cool the place off. In Iowa, in the winter, it can get pretty chilly and when these fans turn on it can cool off the place pretty rapidly.

This alone could account for the condensation / mold on the walls and floor.

As a comparison as to what I see and know having had horses no one up here heats their arena (at least very few), and some owners don't even heat the stall areas. The only areas heated are the tack room and feed room. The odd arena has a heated viewing room over the ring.

Without seeing the situation first hand Mark it may not be all that uncommon what is going on with this particular situation.

As to the concrete floor unless there was a vapour barrier underneath when constructed as you know there will be a lot of water vapour migrating up through it.

Guys
thanks for all of the great replies; their are a bunch of great questions to answer that will get me going on the right track if i get hired to investigate.

Raymond, i looked over the info you in the links you put up and sent them on to my client. I am sure he and I will be discussing this.

Steve, The materials are different there is not near as much interior metal. You are correct this fact alone can make a difference. i did take some measurements but I may be doing a lot more if this comes through. The other barn is not near as nice on the interior.

William, the entire assembly is insulated. There is 14" to 18" in the attic but I haven't gotten to whether or not there is a vapor barrier; this was whirlwind tour at my first visit.

I will let you guys know if this goes or not and what I find. you gave me a lot of good questions to help direct the inspection. It helps having different questions from others with experience.

Good luck Mark!

Mark,
50 horses @ 5gal = 250 gal of moisture to remove. Plus 50 washes. Plus 50 water troughs.

Does this barn have AC?

Is there a drain system for the stalls? Experience with 5 horses becoming 14 horses in an unheated barn and creating a draining system made a difference in many respects.

250K cf with that much moisture is a real engineering design issue. Exchanging the air to remove the moisture is not the way to go for sure. Resolution is more complicated. Having to reheat the exchanged air has to be costly. But a dehumidifier to remove the moisture will be costly though it would supplement some of the BTU for the building.

Will love to hear about the final solution, even if it is next year or the year after that.

Thats exactly what is required - air changes, good ventilation is paramount, even the articles allude to that fact.

Drainage system in stalls is not common, besides horses are exercrcised and turned out so they are not in their stalls 24-7.

Noted the rubber mats in the stall with one photo. Ideally the stall should be bedded with wood shavings, some use peat moss. Critical to keep the ammonia levels down.

I went out for another site visit with my mechanical engineer. we looked it all over again and took a bunch more pictures and are going to process what we observed.
I will add to this thread as we get things figured out.

Your added observations and statistics do help.

The barn does have AC in the stable area.

I will keep you posted as to findings and progression