In general, trusses are not something that you should build yourslef without any previous experince , and / or designing yourself. Go to the librairy and study the different types of trusses and recommendation of. I would certaining go with more than 2 webs, think the added costs is just merely a few dollars, you are getting alot more stability than with just a couple my other suggestion is definitely make a jig when you build them so that all of them are uniform. Built trusses as a class project in vo- tech and even with a jig they can all turn out slightly different which equates to a roof that will be way off and you will notice that alot although you may not notice the slight difference with the trussess themselves. I also might add studying how to brace a truss until you get some sheeting on, if not done properly one truss can domino all the others and you will have a dangerous mess. Bracing the trusses together can be accomplished by good grade plywood and several nails in each per side. I hope that helps out I am not trying to be a know it all and you may already know all of this just trying to point out some often overlooked stuff". I may add you may want to get a quote from home depot, lowes etc., sometimes they build these at a very good price just depends on who they have construct them. Good luck- they are not that hard to build if you follow a howie, fink etc pattern.

 

AS a certified Code Enforcement Officer (fancy name for building inspector) I can tell you that trusses are an engineered assembly and most jurisditcions will not accept home made trusses withouot having an engineer stamp them.

I'm sure Johnboy either is and engineer or has one on staff to stamp the designs. Ask your local building department what their policy is,, you may save yourself some heartache and money .

Just a thought

bubba

 

Johnboy,

Did you get my emails on how to contact me with the specs?

 

I think you should check around for Engineered trusses, I couldn't even touch the lumber in them for the price of the trusses delivered. I think they maybe giving you Home owner prices.

 

mleichtle
I have a question for you. I have built trusses before for a 24 foot wide garage. this summer I am planning on building a 36 foot wide garage. I was woundering if you could give me an example of the truss I need. ie how many webs do i need? and will 2*4 work for the webbing?
I am going to be using 2*6 with 2*4 webs. I want to place a truss every 4 feet.
Will a 4 - 12 pitch work for this?
I don't want to cut any birds mouth at the end. I think that would severly weaken the truss. Instead i will cut the end of the truss so it sits flat on the wall.
Any advice from you will be greatly appreciated.

 

You bring up a good point!

Funny part is, a lot of building inspectors in our area are too lazy to get out of the truck, let alone climb up and look for stamps... Of course, you are right, just a thought you brought to mind.. All I could picture is our local guy, who won't get out of his truck unless you provide coffee and donuts, and then only inspects the portion of the building containing them. He actually questioned a monolithic slab poured as an addition on a garage we built last year, and refused to believe that this method could work, and insisted that footings be installed after the fact...lol.

Thankfully, there are people like you to pass on the proper info, for those of us bless with folks that don't do their jobs...lol

 

Fordtractornut, First I would have to ask why 4' spacing? you would have to ladder frame between each truss because most sheathing (plywood or OSB) is only rated to span 2'.

Yes the way you described would work, I would recomend a double Howe web configuration. do a google serch for double howe roof truss and you'll find some diagrams.

Lastly, and most important, 36' clear span, I feel is pushin the limit on home built trusses. The bottom chord would have to be spliced from 3 boards and those joints are under alot of stress. My software shows a big plate for these joints. A plywood gusset would have to be quite a bit bigger.

A standard truss, 2' on center would be $80 tops. If you can build 'em for less than I'd call that extra cost insurance.

Good luck.

 

I agree with mleichtle, the forces at the truss joints on a 36' clearspan truss on 4' centers it a lot more than you would want to try to handle with plywood. And even if you could get them to work possibly with a bolt through or something, you're still going to have more joint rotation and deflection than with a metal connector plated truss. This ISN'T one for the do-it-yourselfer. I do a lot of poultry house and pole barn trusses and you can do what they call a Post-Frame construction that is very cost effective. It's where you have your Treated posts say at every 10', and you use 2 trusses, one on each side of the post and then use atleast a 2x6 stood on edge between them for your purlins. It usually works out to be a bit cheaper than putting your trusses on 24" or ever 48" centers because it eliminates the need for any band or header at the top of your posts, the load is transfered from the trusses, directly to the posts. Our saw shop is built that way here and it works great because we have a 10' area between the trusses that our forklifts can manuever withough the worry of the masts catching the bottom of the trusses. But I would definately have a local manufacturer build these for you. That truss at 4' on center carries a total tributary roof load of almost 6000 lbs and thats for a minimal snow load and stuff here in the south. It could be more further north.