Condensation

[Hanszmann]

Hey guys I'm newbie here this is my first question post.
My garage has this old rough epoxy concrete, when temperature raises with humidity there is a lot of condensation, my intention was to use Lithium Silicate Densifier to help control this chaos, so my question is:

what type of surface preparation do I need to do? I don't care about the looks, I only need to control humidity, because of my Wood Shop...
I was guessing that if the condensation happens, the concrete porous should be open enough for the Densifier to penetrate, so if I just degrease and powerwash it, would that be enough?

This Desifier, would leave a glossy finish or only if people polish it after?

My epoxy doesn't peal, it is like a grayish sandy look...

As I said I'm only looking to seal the surface and stop condensation.

I really appreciate if any of you could drop some knowledge over me
Thanks!
Dan

 

[bsg]

I'm curious if sealing would work as well?

I have a t shape building, the old section doesn't have a vapor barrier, the new section has a vapor barrier, there is a noticeable difference between the two sections of the building!

When I build a new building, I will not skip the vapor barrier!

Kevin

 

[LegacyIndustrial]

"when temperature raises with humidity there is a lot of condensation"
Get air-flow in there.

Densifier will not help this issue, only air-flow.

 

[Shea]

In order to better understand condensation and what effect coatings and sealers for your garage floor have in relation to it, I found it first helps to speak of it in terms of the paint on your car.

We all know what happens when the dew point raises and your car is parked outside on a cooler night - the surface of the paint collects moisture, AKA dew. Something else you may have noticed is that your car will not collect dew if there is a breeze blowing that night. Why? It's because the relatively warmer and moist air does not have a chance to settle on the cooler paint to condense and dew up, so to speak.

Now, if you wax your car real well or apply a nice coating or sealer to the paint, will it stop the dew and stay dry while your neighbor's cars still look wet? No - it will just bead the dew nicely as it collects on your car. It has no effect in terms of preventing dew on your car.

The same principle holds true for a garage floor. You can put a nice sealer or coating on it, but it will still collect moisture when the conditions exist. Why? It's because the surface temperature of the garage floor remains the same with the coating or sealer. Just as it did with the sealed paint on your car. The moist and warmer air can settle on it and condense - AKA "sweating".

Now, apply the same concept of the breezy night with a high dew point when no dew collects on your car. It's the same principle for a garage floor. If you run a fan across the floor, the air will not have a chance to settle and condense as it is always moving. Sometimes this is the simplest solution to stopping problems with sweating floors.

 

[dave*99]

A friend had his garage floor epoxy coated. He uses the garage as a party space a lot. It's near the shore (NJ) When he opens up the garage doors and sliding door to the space, the floor gets soaked with condensation. Last weekend he had about 12 beach towels strewn about so folks could walk through the space without slipping. There is grit in the epoxy, but it's not sufficient given the summer footwear his guests are wearing.

Cool sealed concrete meets warm humid air.

Prior to this his bare floor was not problematic.
So sealing the surface better makes this issue worse.

 

[Hanszmann]

Thank you so much for your answers, that was mind blowing...

It does make a lot of sense, almost obvious after you explain it...

I have two shop fans pointed to the worst areas, they definitely help, but they don't solve it at all...,

I read some where If I add a layer of plastic floor that would solve the problem, they were saying that would be enough to change the temperature and stop condensation.
what do you guys think about it?

thanks again!

 

[Hanszmann]

Guys one last question if I may, my house locates in the middle of a slope terrain, so I would imagine there is a natural water saturation when it rains and clearly I can see the ground sweating more than usual when it rains.., my question:

Could be that not only the condensation problem, but a combination of over flow of water coming from underneath? Am I over thinking this? If so the densifier could help in this case?

Lastly if the densifier could help, would it penetrates over the old epoxy?

thanks again!

Dan

 

[Shea]

Thank you so much for your answers, that was mind blowing...

It does make a lot of sense, almost obvious after you explain it...

I have two shop fans pointed to the worst areas, they definitely help, but they don't solve it at all...,

I read some where If I add a layer of plastic floor that would solve the problem, they were saying that would be enough to change the temperature and stop condensation.
what do you guys think about it?

thanks again!

Yes, interlocking floor tile will stop the issue. The structure underneath breathes and allows for air flow under the tiles. As a result, the top of the tiles keep the same or similar temp as the air. It essentially insulates the surface of the tile from the colder concrete.

The article in the link below talks about sweating garage floors and the various methods to slow the process down or stop it altogether.

https://allgaragefloors.com/how-to-stop-sweating-garage-floor/

 

[Hanszmann]

Hey Shea,

I appreciate your help, I guess this is the easiest solution then...
Thanks!

 

[yeldogt]

In order to better understand condensation and what effect coatings and sealers for your garage floor have in relation to it, I found it first helps to speak of it in terms of the paint on your car.

We all know what happens when the dew point raises and your car is parked outside on a cooler night - the surface of the paint collects moisture, AKA dew. Something else you may have noticed is that your car will not collect due if there is a breeze blowing that night. Why? It's because the relatively warmer and moist air does not have a chance to settle on the cooler paint to condense and dew up, so to speak.

Now, if you wax your car real well or apply a nice coating or sealer to the paint, will it stop the dew and stay dry while your neighbor's cars still look wet? No - it will just bead the dew nicely as it collects on your car. It has no effect in terms of preventing dew on your car.

The same principle holds true for a garage floor. You can put a nice sealer or coating on it, but it will still collect moisture when the conditions exist. Why? It's because the surface temperature of the garage floor remains the same with the coating or sealer. Just as it did with the sealed paint on your car. The moist and warmer air can settle on it and condense - AKA "sweating".

Now, apply the same concept of the breezy night with a high dew point when no dew collects on your car. It's the same principle for a garage floor. If you run a fan across the floor, the air will not have a chance to settle and condense as it is always moving. Sometimes this is the simplest solution to stopping problems with sweating floors.

Air is air --- moisture is moisture. If the breeze coming in has moisture and the car is under the dew point ... you get more water. IE: sea breeze at the ocean

People have this idea that moving air solves this problem --- it only does if the "new" air is holding less water.

Concrete can hold a lot of moisture --- keep doors open on a humid day and the cold slab is a sponge. Coat the slab and seal it and now the slab can not absorb the condensation and it sits on top.

Fans move air -- they don't change temps or humidity. Moving air changes the way the human body can get rid of moisture .. that's another thing. Feel is not the same

Fans only work when the air being moved over a surface is able to remove the water ..... warmer air can hold more water. The humidity (water) is still there

 

[yeldogt]

Yes, interlocking floor tile will stop the issue. The structure underneath breathes and allows for air flow under the tiles. As a result, the top of the tiles keep the same or similar temp as the air. It essentially insulates the surface of the tile from the colder concrete.

The article in the link below talks about sweating garage floors and the various methods to slow the process down or stop it altogether.

https://allgaragefloors.com/how-to-stop-sweating-garage-floor/

Placing an insulating layer can have an effect ---- an uninsulated slab will still be giving heat to the ground .... by covering it you are increasing the temp of the surface open to the garage. The slab temp is now colder ... so any opening will have an increased potential for condensation.

Dew point is one of those items we all experience but most don't think about -- as a life long sailor it's always on my mind.

 

[LegacyIndustrial]

Air is air --- moisture is moisture. If the breeze coming in has moisture and the car is under the dew point ... you get more water. IE: sea breeze at the ocean

People have this idea that moving air solves this problem --- it only does if the "new" air is holding less water.

Concrete can hold a lot of moisture --- keep doors open on a humid day and the cold slab is a sponge. Coat the slab and seal it and now the slab can not absorb the condensation and it's sits on top.

Fans move air -- they don't change temps or humidity. Moving air changes the way the human body can get rid or moisture .. that's another thing. Feel is not the same

Fans only work when the air being moved over a surface is able to remove the water ..... warmer air can hold more water. The humidity (water) is still there

Play some golf in FL in Summer.
You are sweaty wet.
Jump in the golf-cart, ride to next tee-box, instant relief.
Evaporative Cooling is a real thing.
Same air.

 

[yeldogt]

Play some golf in FL in Summer.
You are sweaty wet.
Jump in the golf-cart, ride to next tee-box, instant relief.
Evaporative Cooling is a real thing.
Same air.

Yes ... it needs heat.

It's potential

Blowing humid air on a cold slab ..... nope

 

[Shea]

People have this idea that moving air solves this problem --- it only does if the "new" air is holding less water.

I think you are missing the point? Warm moist air moving across a colder surface has a much harder time condensing because it cannot settle on the surface to do so.

If you check recommendations regarding moisture mitigation on concrete floors for manufacturing facilities, the first thing they talk about is using fans to move the air. The link below is an example.

https://www.manufacturing.net/opera...to get the,stopping the cycle of condensation.

 

[Showkey]

The link is the perfect explanation of what happening. The fans are trying to change the temperature difference or the Indoor “weather conditions“. Usually not very effective in the garage or basement humidity control. Moving wet humid air over a cold surface makes more condensate.......almost like the floor is giant dehumidifier evap coil, only there’s no collection bucket.

There are dozens of prior threads in the other sections: wet floors, mold, mildew, funky smells, my metal roof Is condensating , ItS “raining” inside, dripping from the ceiling, my welding gloves are moldy fuzz, my garage or basement humidity is 70-80%.

The iced tea glass will sweat or condensate Until the iced tea warms up Or the air temp drops or becomes less humid. In other words the weather changes.

Same applies to the garage slab........it’s cool, warm humid air like 85* 80% humidity the floor will sweat often enough to form puddles. The garage slab is the iced tea glass.

My attached 850 sqft garage is not climate controlled. The garage is well insulated. The home is completely shaded all summer. The garage floor takes a complete season to warm up. The ground under the slab is likely 50*. The garage floor is cool to the touch.

Today the temperature was 81* 57% humidity floor is completely dry.

Tomorrow it will 90* plus with high humidity 80% resulting in heat index 96*. The floor will soaking wet if the doors are left open. I could have 10 box fans it’s not going to dry up until the conditions change.

The Garage floor in winter water never freezes on the floor. Even when outside actual temperatures are -25*.

I have another outbuilding well insulated sealed. I run a dehumidifier to control moisture and the temperature remains @ 68-74* all summer with no AC. Humidity is controlled at 50%.

Other examples:

Condensation is a physical change in the state of matter of a substance. ... Examples of Condensation: 1. Having a cold soda on a hot day, the can "sweats." Water molecules in the air as a vapor hit the colder surface of the can and turn into liquid water.

water which collects as droplets on a cold surface when humid air is in contact with it.

Condensation is the process by which water vapor in the air is changed into liquid water. In other words, the water in the air, a gas known as water vapor, from your hot shower cooled when it met the surface of the cold mirror. This caused the water vapor to condense, or turn into its liquid form.

 

[Hanszmann]

You guys are a wealth of knowledge, I learned a lot.

My situation is really similar to @Showkey, almost same size, insulated but no AC.

So, when you turn the exhaust fan before a hot shower, It makes a difference on your mirror. So air moving can be a piece of the puzzle, but the exhaust is actually taking humidity out of the room, not as much air moving.

Today I have two air movers that doesn't really solved it, I wonder if would be worth it to install a fan exhaust to the attic.

When your ice tea is in a double wall glass, that also makes a difference. So the plastic flooring creating this double layer effect, might be another piece.
I wonder if the interlocking tile must be completely closed...

The dehumidifier seems to be obvious enough, although I wonder the cost of running it versus effectiveness.

Keep the doors closed. I didn't see this one coming, it hit me hard in the face...

As stubborn as I am, I still think that a densifier, might help on changing the structure of the surface, hardening it and making it less "spongy" therefore absorbing less water. Although now I see clear the temperature differences will remain a problem, maybe it would make even more water?!(as it wouldn't absorb as much anymore)..

I learned tons from this community, you guys are amazing!

 

[Showkey]

^^^^^^^ Your theories and understandings are correct:

1 Keep the warm humid air out

2. Condition the air space, but then you must keep the doors closed. In the winter you would not try to heat the garage then keep the doors open. Once you dehumidify the comfort level goes up. The trade off is minimum coming and going.

3. The exhaust fan would draw in make up air that would be warm and wet.

4. Plastic tile like race deck might help slightly........but........suspect once the floor under the decking sweats, it’s going to be very slow to dry out. ???

 

[pcmeiners]

As to concrete floors, if a slab has either a poorly installed or no vapor barrier it will allow a great deal of water vapor to migrate through it every day.

The worst time of the day for condensation is roughly between 2am and 7am. During this time heat radiates into space and the temperature drops sharply, also dark surfaces will drop lower then ambient temperatures (such as black colored cars). Since most garages are not air tight there is a transfer of moisture ladend air previous to 2am, even if the space is not opened during the day. As of 2am on, the space cooled for hours and moisture forms.
Example....
Was a building engineer of a brand new energy efficient school building. Initially the air blowers were left on 24 hours a day. During the first fall I would come in in the morning and there would be gallons of water dripping from the air ducts on the first floor, so much so it required a wet vacuum, even the walls had condensation.
Basically saturated air entered the building during the day (and human perspiration), then the night air cooled the duct works, temperature in the building lowered so the air hit the dew point and the water started to flow. To resolve it without dehumidification, all I had to do was turn off the blowers via a timer between during the night hours, as the building was basically air tight with the ventilation turned off. Surprising how many gallons of water condensed in a few hours in the early am.

Garages are tough, since they are not air tight, they require heating/ac or dehumidification most of the year, slab vapor barriers and decent insulation are helpful but not a complete answer.

 

[Hanszmann]

Thanks Showkey and Pcmeiners,

I'm currently adding a new coat of epoxy, just to see if I can seal better the surface.

I'll do my best to get the doors air tight, using some insulation foam.

I just got the dehumidifier.

I currently have two air movers on the ground, I'll get them on a timer.

I moved the gutter drainage away from the house ( that made some difference)
I imagine my garage doesn't have a vapor barrier. My basement is super dry, but the garage is messy.

Let's see how it goes with those changes, getting educated by you guys probably was the best thing I did to fix this issue, my behavior was terrible.., always leaving the garage open.

 

[pcmeiners]

A humidistat would be your best option, as a humidifier only is mainly needed part time during humid weather or rain, very little during the winter once external temps go below freezing.
Good luck with the moisture issue.

 

[firebirdparts]

Thank you so much for your answers, that was mind blowing...

It does make a lot of sense, almost obvious after you explain it...

I have two shop fans pointed to the worst areas, they definitely help, but they don't solve it at all...,

I read some where If I add a layer of plastic floor that would solve the problem, they were saying that would be enough to change the temperature and stop condensation.
what do you guys think about it?

thanks again!

The concrete is a big heat sink, and it has a lot of contact with the ground, whatever temperature the ground is.. When the dew point of the air is above the temperature of the concrete, dew will form on it. A big surface coating could give you a tiny bit of insulation, but I wouldn't think it would make much difference.

 

[Hanszmann]

Thank you guys,

Now I have the new coat on the floor, I tried to close all gaps I could find, and the new humidifier is working well, most of all I've been keeping the garage always closed.
We didn't have any crazy rain so far, but the garage has been amazingly clean and dry ever since.
Everything you guys have mentioned helped tremendously so thanks for that!

 

[Shea]

Awesome. Glad to hear you have it under control now.