Pole barn make over

[Slong1958]

Hey guys Im needed some help with sizing a I beam for my polebarn if possible. Ive got a 24x40 barn that Im adding on another 12 foot bay on the end and a 12 ft lean to off the rear. My plans are to close in the 2 swing out doors and add a walk-in plus add 2 18 foot roll up doors and concrete the floor. The problem is when I built the barn 25 yrs ago I only built it 9ft tall to the top of the post and Im wanting the know is it possible to put 8 ft doors in. From the ground up to the bottom of the 2x8 ive got 8 ft 5ins. so with the concrete Id have 8ft. Does anyone know how to size a I beam or does anyone have a better idea. In the pics the post that Im pointing to would have the come out to make room for the roll up doors. Ive done a little research and looked at the low clearance garage door tracks which take 8 clearance at the top.

 

[KennyG]

Sizing an I-Beam or wood beam isn't that difficult, but we would need to know the specific requirements. What is the span? What load are you carrying - is this supporting the roof or is it in the gable end? What is the snow loading in your area? I can't quite understand the configuration from your description.

 

[s219]

You must have very little snow load in that area to use a 2x8 header, is that correct? I assume it's a double 2x8 ? That is so close to minimal for even low snow load I feel like it's going to be a challenge to work with that, and even as much challenge to switch to an I-beam and gain headroom. But as mentioned, tell us the span you need to run between posts (with the middle one removed) and it will make the math easier.

If you had rafters it might be possible to come inside the header and put something beefier, but with trusses the header really needs to stay where it is now, to properly support the top and bottom chord where they meet up.

You'd be marginal to get an 8' door in there now -- really need 8' "trimmed out" opening, not rough opening. I think it's going to be a challenge to beef up the header and keep or increase the current head room.

 

[EddieWalker]

I'm not sure that I understand where you want to put the I beam?

It sounds like you want to add a roll up door. Are you wanting the I beam to be a header over the roll up door?

Why?

Roll up doors mount to the posts on either side of the door.

or are you wanting the I beam as part of the area you are adding to the building?

Why? what will it do? How much of a span will it have? Why metal and not a glulam beam? Here, I can get 24 foot long glulams for something like $250 each.

 

[Hay Dude]

Hey guys Im needed some help with sizing a I beam for my polebarn if possible. Ive got a 24x40 barn that Im adding on another 12 foot bay on the end and a 12 ft lean to off the rear. My plans are to close in the 2 swing out doors and add a walk-in plus add 2 18 foot roll up doors and concrete the floor. The problem is when I built the barn 25 yrs ago I only built it 9ft tall to the top of the post and Im wanting the know is it possible to put 8 ft doors in. From the ground up to the bottom of the 2x8 ive got 8 ft 5ins. so with the concrete Id have 8ft. Does anyone know how to size a I beam or does anyone have a better idea. In the pics the post that Im pointing to would have the come out to make room for the roll up doors. Ive done a little research and looked at the low clearance garage door tracks which take 8 clearance at the top.

I have used the low clearance doors in quite a few garages Ive built for customers. They have their place in certain situations, just keep in mind the track hangs low and can get in the way. When Im looking for clearance and need strength, I have used glulam engineered products and also have made my own flitch beams, which are a piece of steel sandwiched in between 2 pieces of framing lumber. VERY rigid and strong.
You can also conceal the header up-in the rafters, attaching the rafters to the inside of the header with properly engineered joist hangers, then nail rafter tails on the outside.
Lastly, you could slope the floor Down lower in the garage addition, but that’s probably least desirable.
You have options, just use the best one for your situation.

 

[Slong1958]

Im needing to get the roof supported and the 2 post removed so concrete can be poored then ill frame in the 2 door openings. The 2 post with the red x will be removed then the openings will be 20 and 22. Ive already got two 22x14 x 1 3/4 LVL that I was going to use and just have 7 foot doors but i got to thinking it would be nice to have 8ft doors. Im just asking if itç—´ possible to use a ibeam and be able to install a 8ft door. Who can tell me what size ibeam it would take to support the roof. The ibeam would need the be no taller than the 2x8 thats there now. It doesnt snow here much so id say no snow load. The barn roof is only supported by one 2x8 on the outside of the post and I havent had any sagging or anything.

 

[Hay Dude]

when you say I beam, Do you mean steel? If so, you need to consult a structural engineer. I was thinking you were trying to do a wood beam :laughing:
I know you want an 8 foot TALL opening, but I think we all are wondering how WIDE of an opening you desire.
What is the width of the opening?
Looks like a 16’ clear span???? If I’m correct, ask a local structural engineer for proper height and # per foot of steel.

 

[Citydude]

One is 20 foot wide, the other 22.

 

[Hay Dude]

One is 20 foot wide, the other 22.

Thanks, citydude
If that’s the case, lumber is out.
You’ll need some good size steel.

 

[Hake]

Snow load will be the largest factor in your calculations. I haven't done the math but a 10/22 steel I beam is in the ball park. Keep your spam as small as possible to accommodate the doors. Standard garage doors are 16 7 and it looks like you want 18x8' so keep your beam at 19' assuming 6" pedestal for the beam to sit on, which is plenty, typically it is ~3". It's worth setting new posts to support the beams to shorten the span.

 

[Hay Dude]

In my little town, we have a PE (professional engineer) you can meet with. Usually he will review my plans or even draw them for me.
In your case, you could probably have him visit your property, take a few measurements or pictures and he will send you a sketch of the area showing the header size, the posts and footings required to support it and the attachment requirements for post to header and trusses to header.
Probably cost you 2-300 bucks. It’ll be money well spent. You don’t want to screw around with the wrong size or wrong installation.

 

[KennyG]

To size your beam, you need to determine the roof load. The lightest that it typically used is 20 lb/sq ft and that assumes a metal roof and no snow load. If your building is 24 feet deep, you would have 240 lbs per linear foot at the beam. Although you have trusses, you can probably assume uniform loading on the beam.

Using the formula W=8fS/l, you need to determine the required S (section modulus) for the beam. Just grabbing typical numbers, assume the steel fiber stress is 20,000 psi. W, the load, for your 22 foot span is 22 x 240 or 5280 lbs. The span is 22 x 12 = 264 inches. The required S is then about 8.7 in**3. Looking at my old beam tables a 6 inch standard weight beam (17.25 lb per foot) has S=8.7. The more common 6 inch lightweight beam (12.5 lb per foot) is S=7.3.

This is pretty minimal design and assumes a very light roof. If I were doing this, I would probably look for an 8 inch lightweight beam and add the posts as recommended above to bring the span down to 18 feet.

All of this is a 10 minute handbook job, so it's your building and your responsibility.

 

[Slong1958]

Here痴 the build sheet on my trusses which has the roof load.

 

[EddieWalker]

By removing that middle post, you have gone from a simple, use just about anything span, to an expensive span. Why can't you leave that post there?

 

[Slong1958]

Eddie when I built the barn I put the post on 10’ center so you have about 9’6” of clearance. I’ve got a lawn trailer and my truck that I park in there and it would be really tight with 9’ doors. I don’t believe my truck would even fit without folding the mirrors in. As I said before I’d like 8’ tall doors but I don’t have to have them I’m just checking. I talked to a local metal supply company and sent them the paper work so I’m just waiting on them now. The guy that owns it is a structure engineer but is out of town so it looks like I’ll have to wait till next week to find out what size metal beam I’d need.

 

[GLyford]

How about putting in a new post, 12 or 14' would be a lot easier than 20.

 

[Hay Dude]

Eddie when I built the barn I put the post on 10 center so you have about 9? of clearance. I致e got a lawn trailer and my truck that I park in there and it would be really tight with 9 doors. I don稚 believe my truck would even fit without folding the mirrors in. As I said before I壇 like 8 tall doors but I don稚 have to have them I知 just checking. I talked to a local metal supply company and sent them the paper work so I知 just waiting on them now. The guy that owns it is a structure engineer but is out of town so it looks like I値l have to wait till next week to find out what size metal beam I壇 need.

I think youre on the right track now. If I wanted a quick and simple solution, Id reduce the width of the opening to 10-12 feet which should allow most anything to pass through. You could do that with ordinary framing lumber. A 20 clear span opening is huge.
My small barn has an 18 foot clear span opening and I admit, I do like it. The first picture shows my 18 foot wide x 10 foot high opening. 2nd picture shows the size of the Paralam I used. And thats a non load bearing front wall! That just keeps the opening from sagging!
I set that puppy with my new holland backhoe and pallet forks. It was about 25 feet long.

 

[EddieWalker]

Eddie when I built the barn I put the post on 10 center so you have about 9? of clearance. I致e got a lawn trailer and my truck that I park in there and it would be really tight with 9 doors. I don稚 believe my truck would even fit without folding the mirrors in. As I said before I壇 like 8 tall doors but I don稚 have to have them I知 just checking. I talked to a local metal supply company and sent them the paper work so I知 just waiting on them now. The guy that owns it is a structure engineer but is out of town so it looks like I値l have to wait till next week to find out what size metal beam I壇 need.

I agree that 9ft is kind of tight. It's also the most affordable door size that you can get, and Lowes keeps a bunch of them in stock. My shop door is 10 feet wide and that was a mistake. I can get my truck and trailer into it, but it's tight and when there is a storm coming, and I have a pallet of concrete in the trailer, it's painful to get that trailer in there quickly. I think 12 foot is the ideal width for a shop door for ease of getting in and out.

I would figure out how to create 12 foot openings and not go any wider by relocating the posts. I would avoid dealing with a metal I beam. That just complicates things. I would make a header out of three 2x8's with half inch plywood between each 2x8.