Window A/C unit installation in metal building.

Well.....LOML gave the approval today to go and pick up some A/C for the shop. I decided on a 10,000 BTU unit and a 8,000 BTU unit for a total of 18,000 BTU of cooling. YEA!!!!!!

Now....how does one that knows nothing about installing a window A/C unit in a metal building that does NOT have any windows.....

1. How much oversized is the exterior hole cut in the wall section?
2. How does the unit get its support when all there is, is the metal skin on the building?
3. Should the metal hole be lined with wood or something to form a frame for the window A/C unit?

If this was conventional construction, I would already have them installed and running...but this is a METAL building and I already have a leaky roof and I don't need a couple of holes in the wall that I can't do anything with.

Any and all help would be greatly appreciated.

Dennis,

I'd wait to cut the holes till you buy the units. The hole just needs to be big enough to slide the unit in. I'd make a frame with the sides running all the way, floor to ceiling. I'd make a plywood shelf that sticks out the outside of the building as large as the unit and brace the shelf solidly to the frame. Once the unit is slid in, caulk the opening to seal it. Your a lucky man! Wish I could get A/C in the shop.

Joe

You'll need to create some form of support frame, not unlike a "window" to support the units. It should be anchored to the floor and wall structure appropriately. I also agree with Joe that you need the air conditioners "in hand" before you do anything.

I have both units sitting inside the shop as we "speak". I just wasn't sure how it should be braced and if the hole cut in the outside metal sheeting should be cut any larger to line the hole with some kind of metal drip cap or "something" to keep the units directly off the metal sheet since they really provide no real structural support of any sort.

Maybe I should take a pic of the insde of the wall to show you better and maybe then you could provide me a better idea of installation.

Be back with a pic shortly.

.............is to make sure the unit is tilted slightly higher in the front than in the back. This will insure any condensate that is not evap'd will drain to the OUTSIDE of the shop, and not on the floor. You mentioned an already leaky roof, so I would imagine that the moisture from that is adequate to keep the humidity in the shop just about perfect! :D (He says with tongue planted firmly in cheek!) Good to hear you have A/C Dennis, that is a COOL Gloat! :p Ok..........I'll go away now..................... ;)

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Originally Posted by Dennis Peacock

I just wasn't sure how it should be braced and if the hole cut in the outside metal sheeting should be cut any larger to line the hole with some kind of metal drip cap or "something" to keep the units directly off the metal sheet since they really provide no real structural support of any sort.

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In addition to Kevin's recommendation to tilt the unit down a little on the outside, you definiately should be properly flashing the opening just like you were creating a window. You want things sealed for air infiltration, insect infiltration and need to insure that water (rain) runs away from the "window"...

Lot's of excellent pointers here guys.....Let me see if I can post these pics to show you what I am looking at for real.

The outside.jpg pic is what the outside metal walls look like and the approximate location of one of the A/C units.

The inside1.jpg pic is where I would like to put one of the units. The OSB wall covering is actually sitting in front of but up against the Red Iron perling that crosses between the two primary section structural supports. Through the metal sheeting and through the OSB?

The unit2.jpg pic is above my BS and above the top run of the Red Iron and is where I would like to put the second unit.

Both units would then be on opposite side of the shop and about 12 feet apart and I plan on running a 36" floor stand fan to better circulate the air inside the shop. I will eventually get around to insulating those garage doors as well as putting up weather stripping around the outside to better seal around the garage doors.

Now....if I got posting these pics correct....you should see what I am talking about....the squares of black and blue is about where the units would go.

Is this any clearer.?

I don't see any major issues here. The unit through the OSB should be easiest as you (assumed) have something supporting that OSB already and it should be adaptable to also supporting the A/C unit. The other one should be fine, too, as you can use the red iron to support the unit...put a piece of rubber under it for vibration dampening and strap it to that beam! In both cases, you'll want to do the flashing I mentioned in my other post to keep out water, etc.

I think you should be alright with the dead space between the OSB and metal. I would take some 1x material and frame the opening inside the metal for extra rigidity. It wouldn't hurt to have some on the inside wall on the OSB either. Initially, I was thinking of some leg supports on the back (outside) to help support it, but the deadspace between the metal and OSB should be enough horizontal strength with the added 1x supports. Looks like your gonna have a comfy shop in the summer too.

Congrats!