More help needed w/ pole building humidity

[jsduke]

Thanks to all who responded to my first post (drainage). All great information (love this site) /forums/images/graemlins/smile.gif .

Since it hasn't rained significantly here in a while and the floor of my building is fairly dry, I'm thinkin' I may have more work to do in addition to the drainage because the humidity is still above 90% (tractor metal always wet to touch) unless the overhead door is left open.

My building is steel clad (sides/roof/doors) with 'single bubble' insulation between roof steel and supporting wood framework. A ridge vent and soffit venting, open to the inside of building, comprises total 'planned' ventilation (no windows or cuppola). Additional air may enter where the steel corrugations stand out from the ground level pressure treated nailer.

While the tractor and other equipment inside bead moisture (mostly but not entirely on the underside) the inside of the steel seems fairly dry(?).

Any ideas on how I can diagnose/eliminate this indoor rain forest? It can't be that good for my stuff /forums/images/graemlins/frown.gif.

Thanks again.

duke.

 

[DavidJ]

You basically have 2 choices.

Dehumidifier. Which will reduce the moisture to a noncondensing level.

Power ventilation. This will be the lower cost but I'm not sure it'll completely cure the problem. I'm sure it'll help because you said it gets better with the overhead door open.

 

[BubbaJr]

I have 6" of insulation in the walls of my pole barn, and 12" in the ceiling. I still had a moisture problem and found that it was coming from the concrete (about 1-1/2 years old). I bought a dehumidifier and now everything is dry out there. Just make sure you get one that is sized for your building.
Good Luck.

 

[Junkman]

</font><font color="blue" class="small">( I still had a moisture problem and found that it was coming from the concrete (about 1-1/2 years old). )</font>

When I poured the floor in my garage & cellar 20 years ago, I put 6 mil poly on top of the gravel and have never had a problem of moisture coming up from the ground below. I did it in my latest garage floor 3 years ago and the contractor said that it is common place now to use it. The only thing is that when they pour the concrete, it must be stiffer because the moisture in the concrete will only come to the surface when they power paddle it. I does take longer to set up, but that is a plus for strength. I also finished the top surface with a clear poly sealer as soon as it was dry enough to walk on ....

 

[jmc]

I think you should start with the floor too. The old timer who is going to concrete my polebarn floor told me that the concrete sealer works so well you don't really need the 6 mil plastic underneath. Although I'm going to put the plastic down anyway, that's a pretty good recommendation for an after-the-fact fix. Cheap too. A dehumidifier would be a very last resort to me with the soffitt/ridge vent openings.

 

[Junkman]

I spilled some diesel fuel on the concrete this weekend and learned for the first time that it will dissolve the concrete sealer and make it tacky. Now I have to wash that area with a detergent and reapply the sealer. I wouldn't skimp on the plastic.... cheap insurance.....

 

[beenthere]

Adding heat to the building will help lower the relative humidity and decrease the wet condensation on the equipment and tools in the building. If you have insulation, heat will be the easiest fix available to you, IMO. Plastic beneath the slab would have been the best, but too late now.

Too many old timers say plastic isn't necessary, but they don't have to put up with the wet concrete slab either. Some who pour the concrete don't like the plastic because the concrete can't be worked as quickly so it takes them more finishing time. The last concrete I had poured, the crew put down two inches of sand on top of the plastic, holding it in place and making the concrete set up quicker for earlier trowling. Seemed to work great.

 

[Egon]

The plastic keeps the water content of the mix at proper levels. The soil underneath can't absorb any water from the mix thus making finishing time longer and requires more site time before the final trowelling.

gon

 

[jsduke]

I guess I failed to say that my floor is not concrete /forums/images/graemlins/blush.gif. The base is an aggregate/dirty fines mix (crusher run). The floor has yet to be topped with a clean fines/agg. material (several inches).

Is there some way I can place plastic down between my base and topcoating maybe using sand or stone dust to isolate the plastic from the larger aggregate below and above to prevent puncturing/tears? Maybe a very thick plastic and/or multiple layers?

Thanks.

duke.

 

[Junkman]

put down a 2" or 3" layer of stone dust and then put the top coat on. 6 Mil plastic should have enough strength to hold up. I would use concrete rather than any other top coat because of the firmness. I have found that when you park anything on a gravel or asphalt floor, that it will eventually sink into the surface.... I would also put wire into the concrete and if you are planning an apron, then put some re rod into the end where the apron is going to be and have it extend out about 2" from the edge of the floor. You can do this by drilling some hole in the wooden form to put the rods through. The only problems is that you will have to cut the wood to take it off the rods.... chances are it is only going to be a 2 x 6 so you won't be wasting much lumber.... I spaced mine 12" apart and the apron has never fallen away from the floor......

 

[jmc]

That seems like a good approach. You may be in luck afterall...

Have you considered spreading a cheap plastic cover over part of the floor for a couple of days to get a feel for how much moisture is working its way up?

 

[jsduke]

Hello Junkman,

A clarification please.

Are you saying to put the plastic down first (on my CR base) then the dust and finally the topcoat?

Thanks.

duke.

 

[Junkman]

put down a stone dust base and then the plastic. The plastic doesn't care which level it is on because the moisture will always be below it. I suggest the stone dust because it will compact well and give you a smooth base for the cement floor. I did my garage floor that way because it faces a hillside about 10 feet away. I also put in a French drain on the side wall at the base of the footing with a 4" PVC pipe to carry the water away. I have seen the water pool 6" high on the side of the building, but the floor has always stayed dry. I have cardboard under some things that I store in there and when I remove the cardboard, there is no moisture under it. Just try to keep the cement people from cutting slits in the plastic. They will do this when you are not looking so the water content of the cement can get below the plastic and they can finish the floor sooner. I caught them doing this on my floor, and I just put down another layer of plastic and told the guy that did it that if I caught him doing it again, that I would throw him off the property and charge him with malicious damage to the property! Many years ago, a worker said that he wouldn't see the problems from his house and I replied that he could leave then. I never let the contractor bring him back on my job because of the poor attitude. Some people just don't care unless it is for themselves.

 

[jsduke]

Junkman,

I'm not putting in a slab. I'm topcoating with a dust/aggregate product which compacts pretty well. Should I put some straight dust on top of the plastic as well as under and then my topcoat on the dust?

I too need drainage, front and right side are downslope. Problem is my underground utilities (power/phone) are approx. 3 ft in front of the building. I've got ample room on the right side but only the 36" in front. Gotta trench between the utilities and the front in order to dump the water downhill and away from my house.

What exactly was done to create your drain and how deep/wide did you go?

Thanks.

duke.

ps. It's become a rarity to contract a service or buy a product and not have problems. Several years back I had a tile hearth built for a woodstove. The guy they sent didn't build it symetrically... nearly an inch wider on one side as compared to the same tile on the wall behind. It was very noticeable. When I flagged the owner on it he told me it wouldn't be seen after they installed the trim (which I requested). I insisted that it be made right which he did...but not without a pi** fit. The trim they were going to install turned out to be crap (looked like it had been salvaged) and I told them to skip it. I could go on for days about this kind of stuff /forums/images/graemlins/mad.gif.

 

[Junkman]

OK.... now I understand the problem more clearly...... if you put plastic down and then put another layer of stone dust on top, the plastic is going to hold the moisture below it, but if the top layer of stone dust gets wet, it will not dry very quickly and you will have another problem. If I were in your predicament, I would reconsider the concrete floor.....
As for the drain that I installed, it is a 4" perforated pipe that has a "sock" over it to prevent fines from getting into the holes. That is covered with 3/4" crushed trap rock and then there is a layer of "cloth" that prevents the top soil from migrating into the crushed stone. The total depth is about 24" with about 18" of it being stone & 6" being top soil. The water will pool on top, but it will also dissipate rapidly. Almost forgot to mention that I put down a thin... 3" layer of sand/stone dust to cushion the 4" perforated pipe first...
It is about 12" wide and has a 1/4" per foot pitch.. The idea is to get as much water away from the area as fast as you can.
If you are careful, the 3 feet in front is enough to work in. I would also put a drain in this area rather than just using a solid pipe here...... might as well keep everything as dry as possible.....
If you know someone that has a Kubota BX22, it is the perfect size for a trenching project such as this... I know, because I have a BX22 with a 12" hoe bucket.....
the Junkman

 

[jsduke]

No $ for the slab at this time /forums/images/graemlins/frown.gif.

I guess I've got to minimize the amount of water that reaches the 'above the plastic' layer. Outside of some snow melt from plowing and if the tractor gets wet and dries inside I don't expect a lot of new moisture except migration from below and from the sides (rc wicks a bit). The front and right side drainage will keep major ground flow at bay so all I need to address is proximity rainfall/snow melt and roof runoff.

If I can isolate the 'above the plastic' layer from side migration it's gotta help. What if I allow for an additional 2 ft. in width and length when I size the plastic so I can turn the edges up vertically to block from the sides and ends?

I wish I could get a 'Mulligan' on this structure /forums/images/graemlins/smirk.gif.

duke.

 

[Junkman]

can't see how that would hurt anything... turn up the sides and hope for the best....