A shed is born,finally

praha · Feb 20, 2007

Eddie,
I think a condensation occurs when warm air with a moisture content comes in contact with a cold surface .
Insulation eliminates that,therefore no condensation.
Sometimes air ducts going thru unconditioned space must be wrapped in insulation to eliminate unwanted water condensation. OR dryer vents /long/ going thru unconditioned space/attic/ may develop a water condensation and eventually ice formation. That stops the airflow. No airflow equals unhappy wife...........................................................no need to continue.

Joe

EddieWalker · Feb 21, 2007

Praha,

Warm air trapped in a building will hold allot of mosture in the form of humidity. When that air tempature lowers, the moisture content will increase until the vapor turns into liquid. When this happens, you have condensation. Some call it sweating. Either way, it will look like rain inside his building.

The insulation will actually make it worse, because it will trap the warm air from the day inside the building. When that air lowers in tempature from the day cooling off in the evening, or during the night, he will have moisture issues.

The only way to get rid of this is to either vent or control the air tempature. Venting is allot cheaper.

Eddie

praha · Feb 21, 2007

Eddie,
insulation is used for a moisture control. There are gradual temperature changes within an insulating materials,let's say from 90 inside to 40 outside.
At 90 degrees warm side will have a dew point,/condensation from vapor to liquid occurs/ around 80 degrees. If there's no effective vapor seal, water will start to condensate inside the insulation...
and at this point I have no idea, what was done there. He also mentioned soffit vents. ...this is just a theorie.
Just from a different perspective, why , in winter, my windows are wet and not my walls. If insulation makes things worse, I should have wet walls and dry window, shouldn't I....lol.
I would trust the builder, he is the one who should know.

Amen.

Joe

EddieWalker · Feb 21, 2007

Joe,

I didn't mean to imply that insulation makes things worse and didn't realise that anybody would get that from my post. That wasn't my intent.

Insulation is not used for moisture control. It's used for air tempature control. The vapor barrier serves two functions. One, to minimze air movement. On most homes, this is only minimally effective. The other reason, and where we disagree is it's use on moisture control.

The changes in tempature from the inside and outside of a building will create condensation. This will form on any surface, of any thickness if conditions are correct. It's very obvious on metal roofs because metal is such a great conductor of electricity. The same is true on a soda can. But foam cups will have condensation on them as well as a building with a very high R factor.

The Insulation will keep the inside tempature constant more efficiently, but it's still failing and letting hear or cold through the walls or ceiling. There is always a point of chang in air tempature where condensation will ocur. Most of the time it's too minute for us to notice, but it's happening all the time in most areas. Only extremely dry air is imune to this, and even then, it's rare.

The potential problem I see with the shed is that the insulation will trap the warm air inside the building and when it cools, it will form condensation. There is no place for it to go with the peak totally sealed in. It would be the same if he didn't have insulation, but more pronounced.

Eddie

keving · Feb 21, 2007

You have about the same gap at the peak as I do on my 24x24 garage. I have just regular attic insulation. I have no condensation issues. I do get some leaf matter blowing in during the fall. I'm guessing you won't have any problems... Sweet building!!!

bones1 · Feb 22, 2007

Steverino said:
Bones,

As far as the question of venting, I think I can see the light coming through the top of the roof and it appears in picture that there is a gap of several inches at the ridge after the roofing panels have been installed. If so the cover on top of the panels would the finish the venting system allowing air to escape between the cap and the panels. On a dark night shine a good light up there and you should see the gap inside and some light reflected to the roof on the outside. Or throw up a ladder on the inside and take a closer look.

Steverino,there is a continuous roof vent or ridge vent they tell me,so the gap you see would be correct.
I have discovered a problem with drainage now

.The right front corner of the bldg is low and water runs under the bottom plates into the bldg.Take a look at the the right front of this picture and you will see what I mean.
http://i24.photobucket.com/albums/c29/shenders/bldg/barn067.jpg
How would you guys divert this water if it we're your building.Some kind of french drain,pipes?.Would another row of say 2x6 skirt boards installed under whats there now help?.I could dig down and install them.I do have to dig the hill back some to get in the man door also.

EddieWalker · Feb 22, 2007

I'm not a fan of french drains and consider them marginal at best when you have no alternative. I would dig out more of the hill and let the water slope away from the building and then drain through an open channel. Since you plan on digging there anyway to open it up for the door, it sounds like the perfect oportunity.

Nice to hear about the vent. I couldn't tell by the pictures, so it must be a very low profile one. Very nice.

Eddie

praha · Feb 23, 2007

Eddie,
I have read many of your posts. You are very knowledgable person. And a great help to many people. I have no doubt, that we are talking about same thing , except our wording/perspective may be little different. Since the object was a pole building I talked about a purpose of insulation in this particular case. And that is a moisture control. Of course , insulation is mainly use for heat control.
Well, it has been a l o n g time since I finished my HVAC classes. I am a heating/cooling contractor, and a moisture problems are not what I have to deal with daily.
This was just a little challenge to refresh my theoretical knowledge. As I said you are good.

Joe

Steverino · Feb 23, 2007

bones1 said:
I have discovered a problem with drainage now .The right front corner of the bldg is low and water runs under the bottom plates into the bldg.Take a look at the the right front of this picture and you will see what I mean.
http://i24.photobucket.com/albums/c29/shenders/bldg/barn067.jpg
How would you guys divert this water if it we're your building.Some kind of french drain,pipes?.Would another row of say 2x6 skirt boards installed under whats there now help?.I could dig down and install them.I do have to dig the hill back some to get in the man door also.

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I would think that a natural slope away from the building would be the best solution. A low maintenance, low cost, approach. Simply dig out a little about where the eve overhangs stop and use that soil to bank up to the bottom of the building so that water would run into the channel. At this stage it only looks like a little shovel work. When it rains the water dripping off the eves will slowly erode and compact the soil further creating a better channel. If this channel gets to deep or severe you could line the channel with pea or crushed stone. In the back where the bank drops off I would use a larger stone or riprap to prevent serious erosion. This project would entail mostly elbow grease for a simple solution.

bones1 · Mar 22, 2007

http://i24.photobucket.com/albums/c29/shenders/barn088.jpg
Have to run electric service next.Changing the meter on the outside of the house to a dual feed meter so I don't have to mess with the panel inside.I'm told that's the best way to go.Thanks for looking.