Why not a double sliding door? Do you have 20 ft on either side for the door to slide on the exterior side? I'm very happy with my Morton sliders on both ends of my 48 X 60 building. They're light enough to slide open with minimal effort. A creative guy could probably design automatic openers if he wanted. I thought about it but don't really need that for my use.

 

Why not a double sliding door?

Shop is 70 ft wide. Also a slider does not seal up good enough fo a heated shop. I like the idea of a automatic slider . never thout of that.

 

The only doors I've ever actually seen 40 ft wide and 18 ft tall are those "bifold" hanger doors. I'm thinking they'd be pricy with springs and counterweights, openers, whatever you need to lift that huge thing up and keep it up.
As for sliders, I think you can get weatherstripping that will help greatly for a heated building, but I'd defer to other people who've done it since my building is uninsulated and not heated or cooled except by God (and he can be a little "heavy handed" on the extremes!)
Go talk to a Morton salesman even if you don't sign a contract with them. They should be able to show you possibilities and you can get ideas. Maybe you'll want to buy the doors from them, who knows. But I do think they have some answers you seek.
Good luck.

 

Hydro swing:

http://www.hydroswing.com/

 

I agree 100%. Installed a couple for a hangar I was GC'ing in NH a couple years ago, Ill see if I have any pics. The customer service was A+, and they were extremely easy to install.

 

What size and type of beam do you have above the area you want the door at?
I have two 12'wide X 10' tall overhead doors that when both are opened I can remove a center 8" piece, that incorporates the door tracks as well, and this gives me approx 25' opening.
I know it is smaller than you want but you might find two 20'x18' doors to make it work. This way you also don't have one large opening in colder temps.

 

What size and type of beam do you have above the area you want the door at?
I have two 12'wide X 10' tall overhead doors that when both are opened I can remove a center 8" piece, that incorporates the door tracks as well, and this gives me approx 25' opening.
I know it is smaller than you want but you might find two 20'x18' doors to make it work. This way you also don't have one large opening in colder temps.

That is a very good idea!!! How well does it seal up. Also how long does it take to remove the center section? I will also have a 20 ft door on the side wall for the smaller items.

 

On mine the center piece is simply removed by hand. It has a piano hinge on the top so that it can be lifted up when the doors are open but it has been cut (by the previous owner). It only takes less than a minute to remove it.
The bottom is locked into place by a spring loaded pin into an alluminum plate that is bolted to the floor.

 

Our 40 by 20 bi fold leaves about an 18' opening and combines are starting to hit if you dont get the gaurd rails and extensions folded up. They are only going to get bigger.

 

Our 40 by 20 bi fold leaves about an 18' opening and combines are starting to hit if you dont get the gaurd rails and extensions folded up. They are only going to get bigger.

Thanks for the info!! I better specifi the opened height that I want. How do you like your bifold door? Would you by another? How well does it seal up from the weather? Thanks

 

Winter seal is'nt bad at all. It has been in place 14 years and goes up and down 1 to 5 times a day. We also have floor heat though so you can open the door and close it when its 20 degrees out and 5 minutes later the whole shop is warm. We added additional hinges a couple years ago to help the old ones which are wearing and starting to crack. The door is on the east side of the shop and when the wind blows out of the North real hard in the winter we run a chain to the middle of the door from a tractor or fork lift cause it sucks the door out real hard. We also have a large garage door on the west over a wash bay and if the wind is blowing with any strength from that direction the bi fold only gets operated if that door is closed.

 

We also have floor heat though so you can open the door and close it when its 20 degrees out and 5 minutes later the whole shop is warm.

In floor heat or overhead radiant tube is the way to go. Recovery time is much better than forced air.

One note on the slider doors. I service a few aircraft hangars in town and they are replacing the door seals often. They simply don't last.

 

I'm sorry if someone already posted this but I was just looking at Schweiss Bi-fold doors for a hanger today. They have a fantastic web site and an informative FAQ section that might help you.

 

We've got a Schweiss bi-fold door in our shop. 34'x16'. Works great. We went from 2 17' sliders that took two people to open and would freeze shut in the winter and didn't seal very good.