# Hangar Door

Discussion in 'Workshop Tips and Secrets / Tools' started by bmcj, Aug 30, 2015.

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1. Aug 30, 2015

### bmcj

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Hi all,

in in the airpark home we are buying, our hangar is open-front (no doors). I like the open-front look, but really need a door, so we will be looking for some kind of door.

My my question is, in an effort to keep the door light, rigid, and inexpensive, what does everyone think about making a bi-fold door out of fully-wrapped foam and fiberglass sandwich panels (upper and lower panels)? can it be done and be rigid enough across a 42' span as long as the middle is supported by cables?

there's a 'twist' to my story which I will offer later, but I first want to know if this approach could work for a rectangular opening.

Bruce

NOTE: OK, I'll admit that I could do some of my own calculations, but I'm being lazy (saving energy for putting up the door later).

Last edited: Aug 30, 2015
2. Aug 30, 2015

### Vigilant1

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I'd think it could work, but it would be an expensive hangar door. Well insulated, though. Also, you may want to talk to your insurance company and see the rules of your airpark about the ramifications of building a major part of the structure with a flammable material, I would think they'd want something with a lot lower flame spread rating than XPS/EPS typically has. And the cheapest way to get the rigidity you'd need is to use very thick cores (=more flammable material). I know I would be concerned about the fire issue if I was in an adjoining hangar.

Last edited: Aug 30, 2015
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3. Aug 30, 2015

### TFF

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A normal 42' bifold door is about 4000 lbs. My companies 55' one is 6000. If making it yourself, try, but it is probably going to have to have steel in it; 42 ft is a good span. Even if lighter, they will be heavy for manhandling. We got rid of the standard FG insulation; it would get wet in a heavy rain; probably lightened the door a 1000 lbs water weight from rainstorm days.

4. Aug 30, 2015

### Joe Fisher

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5. Aug 30, 2015

### BJC

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bmcj:

I don't know where your new home will be, but if it is anything like here (Florida) the building code wind loading requirement will require a PE seal on the drawings to certify that the design will meet the code.

BJC

6. Aug 30, 2015

### bmcj

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Ouch, you're right. I know the HOA would be fine with it, but I'll need to check the county ordinance.

7. Aug 31, 2015

### Eagle

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Our local grass roots airfield uses a homemade bi-folding set of doors. It ends up being four panels, two for each door. I think its a little less than 40 feet. Each door has a small wheel at the fold in the door and the end (center) of the door. They are made with a steel frame covered with metal siding, then sprayed on the inside with foam. They work pretty well, but obviously aren't as nice as a one piece overhead door. With a little searching they probably could be made of some lighter materials.

8. Aug 31, 2015

### Hot Wings

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I've not build one exactly like you describe, but plan to.

I built one of my shop doors, a 12 x 12, out of 2 layers of 1" glass faced Isocynate foam board* with one sealing layer of chopper gun polyester to hold the whole thing together. It has 2x2 14 gauge steel at the hard points. It's nearing 2 decades of use with no problems, including a couple of klutzes backing into it. I have another 10 x 12 hole that I have all the hardware for to build a bi-fold using the same materials and don't have any worries it will be just as tough. Building code in my area is 120 mph and I now the door has seen 2/3 of that on several occasions.

*free from the scrap pile at a local fiberglass company.

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9. Aug 31, 2015

### Birkelbach

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I built a 60' x 16' bifold door for my hangar. This is NOT a trivial undertaking. Do not underestimate the loads that are imposed on the building. If the building structure was not designed for the loads imposed by a bi-fold door you will most likely have to modify it. I calculated that my door should weigh between 4,000 and 4,500 lbs. When the door is open this is around 9,000 lbs of lateral load on the top of the building trying to tear the top of the opening off. The same 9,000 lbs is pressing inward on the two rollers that each have to deal with half of that. The more you open the door the worse these loads become.

The door in Joe Fisher's album would considerably reduce these lateral loads. You can also build structure outside the building to hang the door from. I've seen this done on Quonset hut type buildings. It's not nearly as pretty but it's better than ripping the top of your building off. It also solves any irregular (not rectangular) shape issues.

Don't underestimate the wind loading either. At one point while I was working on my door it was hanging free ( I hadn't yet installed the guides on the bottom ), I had the 12' door on the other side open and a ~5 mph breeze blew in. It pushed the bottom of the door out about 3 feet. Scared the beejeebees out of me. Close the 12' door, grab lot's of C-clamps and get those bottom guides finished right now. It was impressive. My door has since seen >70mph winds and held up just fine. No hurricane yet but that day cometh, I'm sure. I don't remember what the calculated wind load was on my door but it was surprising.

Rigidity is not as much of a concern if you have enough hinge points on top and enough lifting points on the bottom. I have 11 hinges on top and 6 lifting points. My door sags at the fold ever so slightly but it had to be measured it's difficult to see. To eliminate that I'd need to build a truss outside, or change the material that I used for the fold line.

I have a hard time believing that any fiberglass type material would outperform steel in either weight or cost. It would be well insulated though.

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10. Aug 31, 2015

### Hot Wings

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You are right about the loads. A typical stick built house with an open hangar attached is probably not up to the loads without some modification. The hole I mentioned above that I intend to plug with a bi-fold was built from the start with this in mind.

I decided on foam/glass specifically because it turned out much lighter* than a built up steel framed door, and reduced the loads the building needed to withstand. Cost for the foam/glass was higher than steel frame and steel/fiberglass panels for the door. Once you figure in the cost of modifying the building the difference might not be so great.

Insulation in Fresno might not be much of a factor. In my location the extra cost is offset in reduced heating bills very quickly. Cuts down the noise too!

* just like aircraft structures weight gain and the resulting needed strength can have a cascading effect. This weigh difference might be much greater for a 40' door, depending on how many support wires are used.

11. Aug 31, 2015

### BJC

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Last edited: Sep 1, 2015
12. Sep 1, 2015

### lake_harley

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I just installed the steel framework for a set of doors like Eagle described in his post. Unfortunately, I didn't have a camera along today to have taken any photos, but will do that to add to the thread when I can.

I had a 8' X 34.5' opening to fill. I used 4 door panels. The two center panels will fold out 180 degrees to be face-to-face with the outer panels. The two outer panels then each open outward 90 degrees. I fabricated my own hinges since store-bought stuff didn't look up to the task unless I got into some pretty pricey hinges. The framework is a combination of 14 and 16 Ga 1" square tubing, basically a rectangle with horizontal and vertical crossmembers and one diagonal in compression. I also added a second diagonal (to complete an "X") out of some 5/8" 16 Ga. square tube I had on hand just to give more places to mount the 29 Ga. steel roofing/siding material I'll use to cover it, which matches the rest of the metal on the building.

I'll have points on the inside to pin the doors in place and only one of the center doors will be able to be opened from the outside.

I came up with a total weight of the entire assembly of about 300-ish Lbs. I used 6" X 3/8" "super lag bolts" to mount the hinges to the wooden corner posts. Those lags really have deep threads and I think the building will come down before they pull out.

I'll have to admit I did no wind load calculations, but generally our strong storms come from the Southwest and my hangar faces East. Compared to some of the other rickety doors on the hangar building I can't see mine being any more likely to be ripped up in a storm than they are.

I'll try to take and post pictures ASAP.

Lynn

13. Sep 1, 2015

### mcrae0104

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Keep in mind that the leeward side of a building can face significant negative pressure.

14. Sep 1, 2015

### Vigilant1

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If a door gets blown off a hangar and damages another hangar or an airplane, we can all guess who will get the bill. It will be tough to defend against that if there's no engineering data to indicate the door meets applicable codes/standards. That could be mucho expensive.

15. Sep 1, 2015

### lake_harley

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I'm aware of that.

As far as codes and standards there are no codes at the airport's location where I am putting my plane. I'm not making light of building something correctly though. If my doors get blown into something else at this airport though, I'm convinced there will still be parts of the hangar attached to the door panels.

Lynn

16. Sep 1, 2015

### Vigilant1

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Okay. But others, people who might live in the US, their hangar will be in a city (maybe), a county and in a state (or territory), and those entities have building codes that govern these things. They might have customized codes or just use a standard code (like the IBC, MBMA, ASCE, UBC, SBC, BOCA, etc). In any case, if a hangar door blows off (or takes part of a hangar with it as it blows off) and does damage to an airplane or hangar (including the one inside), the affected insurance company or individual will check to see if the door met those codes. If it didn't, then they'll look to recover damages from whoever was responsible for installing that door.
I'm no fan of our overly litigious culture, but it is what it is.

17. Sep 1, 2015

### lake_harley

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Vigilant1....You are absolutely right and I agree. Like it or not, we all have to live within the system. Please know that although my reply might have come across as rather smart-aed, I didn't mean it that way.

Lynn

18. Sep 1, 2015

### Pops

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Zero building codes in the county where I live. Zero. With 5808 people and no stop light.

Dan

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19. Sep 1, 2015

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Why are there not more "slide in" doors in the US? A horizontal split (or more) in the door and it slides on tracks, up and then inwards in the hangar? Saves most of the wind and water exposure?

20. Sep 2, 2015

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