Truss Terminology

[Kirk_Allen]

I was pricing some prefab trusses to get an idea of the cost for the shop I am going to build and have a question.

A 3-12 pitch truss for a 60x40 shop with a 2 foot overhang.

they price was $186 each and it would be 20-4-10 made from SYP.

Can anyone explain what the 20-4-10 means.  I assume it has to do with the load raiting but felt better asking hear than at the lumber yard.  

I would think it would be cheaper to build my own but I dont have access to any lumber that would work for a 40' + span.  

Any advice on the best way to go would be appreciate.

Thanks

[Tom]

Look under "information" at the top of the page and click on "Links Library".  The first entry is a document on framing.  it may not answer this question but may help down the road.

I had a customer that built a Hay barn with a 38' clear span with conventional framing of rafters.  He used 2x8's resting on a plate similar to the drawing in fig. 51 but without ceiling joists.

[WH_Conley]

http:www.public.iastate.edu/~mwps dis/web/tr plans.html.
Hope I got this right. Someday whin i get educated I might learn how to paste an address. This site has a lot of good info and plans, of course you can always modify the plans.

[Furby]

Don't quote me on this, but I belive the 20 is the live load rating, the 4 is the static load (load of the sheathing and roofing), and the 10 would be the dead load (snow), all PSF.
I could be way of base though.  :

Let's say you are doing a 4/12 pitch roof, 40' span. That's just under a 24' run (with the 2' overhang). You can do that as rafters useing the wooden I-joists or other prefabed joists. You would have to figure out the strength of 2x for that span, but you might be able to use 2x at 6" centers or something close. Just a guess. :

That seems a little steep by way of price for those trusses. Are they standard 2x4 top pieces with 2x6 bottom pieces?
Have ya looked at the post and beam trusses? They can be spaced much farther apart, just need heavier sheathing. :

[Kirk_Allen]

What they quated was 2x8 material.

Correct me if Im wrong but if I use 24' I joists I would have to have a support in the middle wouldn't I?  My goal is open floor space for the shop.

No, I have not looked into Post and Beam trusses.  The truss they quoted is for 8' centers.  Not sure if I need to go any further appart than that but will look into it.

Who sells the Post and Beam trusses or are they similar to Timber Frame?  I would like to Timber Frame it but Im back to the issue of wanting 40' of open floor space.  I dont want a support pole in the middle of the shop.

[Buzz-sawyer]

Kirk the longest chord is only 18' for this 40' truss heres a plan for ya.
http://www.public.iastate.edu/~mwps_dis/mwps_web/tr_plans.html    

[Larry]

I used Midwest Plan Service years ago before there was an internet to build a shed and it came out great.  They do good work and the price is right. ;D

Made a friend that owns a small truss company few years ago and found an even better method.  They got truss software – just plug in all the variables and out pops the truss plan.  I built some out of cottonwood this summer.  They were 36' long and after tweaking the program the longest board I had to saw was 12' long.  We had to substitute some kind of pine with similar strength properties as the program didn't have cottonwood in its database.  Next step was dumpster diving in a new subdivision where they where building a lot of new houses.  We fished out scrap plywood to make the gussets.  The final stop was the big box store to pick up PL adhesive and nails.  That was the only money out of pocket.

Probably a bunch of different ways to skin this cat so a little research can pay big dividends.  My Morton shed is one of the better built factory buildings and it uses trusses on 12' centers.  Its always best if you can make your building length a multiply of the truss spacing.  8' on center would be either a 56' or 64' long building.

[FiremanEd]

Evening Kirk,

We had to pay $104 each for 36' + 2' overhangs in august. These are 4' on center. If what they quoted was for 8' on center I'd think that'd be hard to beat. Even though you can build them or frame it in it would take a LOT more time than setting the trusses. Guess it comes down to time or $$.

Saw George the other day, he said to tell you hello.

Ed

[Furby]

Those 2x8 material ones are the post frame trusses I was talking about. 4/12 slope, 9' on center, the price I have is $169 + delivery, as of a couple of months ago.

Standard trusses are listed up to 32' at $68.99, 2' on center. I don't know how much the standard trusses would be special ordered at 40'.

Now the I-joists I don't know. I've seen them done as regular rafters instead of on top of the ridge beam, but not that long of a length (60').

The truss plans are an option, but you may have to have them approved by an engineer to pass code, depending on the codes in your area.

We did my grandparent's addition floor with 2x10's, clear span 20', 12" on center. I belive the inspector was going to let them go at 16" o.c., but my grandpa wanted 12" o.c.. I was in there today and that floor don't bounce one bit!

The actual length will be just under 24' at 4/12 pitch for 40' with 2' overhang, but the span it self will be a little under 22'. I would bet you could use 2x12's for rafters at that span, and maybe go 16" o.c. or 18" o.c..
The rafters would be the support for the ridge beam, so no posts. That would probly be the way to go in my book, but I don't know how the $$$ compare.

One thing to remember with the post frame trusses or having a larger spacing, is heavier roof sheathing and the cost of that. With something that is 24" or less o.c., you can if you want, use regular 7/16" OSB.

May I ask how you plan to build the walls? Pole type building, or stud framed? How high?

[Kirk_Allen]

Right now I plan on building stud walls from 2x6 or 2x8 Ash.  I have more than enough on hand to cut them but am still planning on the size of the building.  I would like to have two stories so that the second floor could be used as a rec room above the shop as well as a main office.  

Thanks for all the info.  Its a great help.
Happy Turkey Day!

[Furby]

In that case rafters would work out great because you would only need 4' or 6' sidewalls on the second floor. The rafters will give you a lot of head room.
One other problem is the 40' span for the second floor. You don't want any posts on the ground level, so you need to clear span the second floor joists.
I have the info right here, and you can do up to 40' with a "floor truss", but they are not going to be cheap!
Might want to think about putting in a line of posts down the middle, or maybe only haveing a 30' x 40' section with a second level. Half of the gound level would have posts, and the other half would be wide open. Could have tall ceilings in the half without a second level.
Just something to think about. :

[Kirk_Allen]

What ever you have Furby send it my way.

I was thinking along those same lines of only half being two story and the other being high ceiling but still planning.

The slab is going to have the radient heat put in it and Im still trying to isolate the best system there as well.

Lots of planning in hopes of doing it right.

I have even thought of going 30x 80 instead but not sure yet.

[Furby]

I was at Menards today and asked about those truss joist.
They have a flyer at the contractors desk if you want to read about them. There is no website listed on the flyer, but I'm guessing something would show up on a google.
If you go to Menards, they can lookup the size and price for you. I don't know about the other box stores, I was at Menards, so I asked.

A 30' span is a lot cheaper to do, based on what I've seen. It will depend on what materials you use though.

The 40' span is the max these truss joists are rated for. They are 24" tall, and are spaced 12" o.c. for the 40' span. The price they gave me is....................................................
$4.39 per lin. foot, in other words....$175.60 per joist + taxes and delivery. How bad did ya say ya wanted that second floor with no posts on the first???

Something else to think about is the height of the building. From the looks of the pics you have shared, you are in a pretty well open area. You will have to consider the wind factor. But I sure would not go with 8' side walls. I have a 32'x40' pole barn/garage, and it's pretty much useless for anthing other then storage, due to the 8' walls. What are your plans for the roofing? The post beam trusses sound like they might be cheaper as long as you use metal roofing. I would think they would be more expensive if you use shingles, due to the heavier sheathing required.


Just my 2 cents, but I think I would consider several smaller buildings or at least a smaller building off the big one for the office/rec room, and not put in the second floor.

Are there any places near you that do commercial buildings?
They may be able to do a steel building for you, for a comparable cost.

[Kirk_Allen]

Furby:
What is the challenge with 8 foot walls?  

I have looked into steel buildings but since I have more than enough Ash on hand I thought I would build it my self from what I cut.  I plan on using radiant heat in the foundation and insulating the walls so I'm missing the issue with the 8 foot walls.

I think your probably on track with doing a smaller building for the office etc. instead of two stories but Im still crunching numbers.

I do have a quote coming from another steel building company and its supposed to be a wholesale price. Dave, the guy that came up from Texas to hunt builds them on the side of his full time Firefighting job.  He said he could get it to me for cost so I am waiting to see what that price will be.

I plan on using steel roofing.  After roofing the farmhous last fall I dont think I want to do any more roofing work of that type ;D

[WH_Conley]

Kirk, a few different angles:
 (1) I don't know about your market there, but if you have a decent market for ash you might think about selling it and go with steel.
 (2) I think I know what Furby is talking about on 8 foot walls, forget about getting a machine inside to do anything, loader-forktruck. I built one building 13 ft headroom, worked great, the place I own now has garage 8 ft, all I can do is walk in it, 7 ft door, tractor won't fit.
    

[Furby]

Let me ask you this, what are your planned uses for a building that size?
When you get to a certain size, it feels really small for 8' walls with say 40' of distance to the next wall. Right now I wish I had spent the extra money for either an open ceiling or 10' walls in the addition, and that's only 28'x30'. I can't get anything through my standard garage doors other then cars/trucks, small boats, lawn tractors and so on. I'd love to be able to drive the backhoe in when I pour the floor. Can't do it! I have piles of pallet racking, but have to cut them down to 6' in order to use the 8' height. I could bring my mill in my garage if I wanted to, but the logs would have to be moved and handled by hand. You can't use much of a hi-lo with  8' walls either.
I helped a neighbor build his barn. 24'x32' with 12' sidewalls, 2x4 framed. It had one standard garage door and a 12'x12' sliding door for the boat. That height made a WORLD of difference. The next summer he built a new house and this time made the barn 32'x36' I think, with the same 12' walls. It was even better.
Heating will be a problem with taller walls. My suggestion is figure out your uses of the space, and if needed have a section of the building that has taller walls. A wood working shop don't need 10' walls. If ya are going to build something in your shop that is 8' tall though, ya better not have 8' ceilings, or ya have to build it on it's side. If any of the space is going to be used for boats, or tractors, or ya might work on cars, maybe you'll want to get a travel trailer in there some time, have a section with taller walls, even if it's only a small bay that's 10' tall.

Don't spend a lot of extra $$$ for the extra height, but consider the uses. If I was putting in a building that size and was only going to have 8' walls, having the support posts for the roof or even the second floor really wouldn't bother me becase the space isn't as high. Just my opinion, that's all.

[Kirk_Allen]

Thanks Guys!  Lots of great input and I appreciate every bit of it.  

I have been so focused on building it that I had not even thought about getting a tractor inside, which I want to do.  

Its amazing how the little things can bite you if your not careful.

Thanks so much!