Carpenters, experts help with (free) trusses building size.. photos

[jubylives]

Those trusses look fine. Maybe a little issue on the ends. I built these for years. I built trusses from under 12" to trusses over 90' in length. The connector plates are plenty strong for the design of the trusses and the forces applied to the joints. You've been given some good advice. I would definetly add tail scabs as they are called to the ends to create the over hang then you would have the 10' building with overhang. Remember this when thinking of how tall the walls will be. I'm off to work now but I will add some links when I get home for reference.

jeremy

 

[Ridgerunner]

I'm a retired civil engineer but my expertise is in large steel welded construction, not wooden trusses and wooden construction. I'd certainly pay a lot of attention to the people who deal with this for a living.

I agree with the mechanical engineers. You'll get better stress flow, less stress concentration, and less deflection if you support the trusses at the ends. That is how trusses are designed.

The design snow load for Faytetteville is 20 pounds per square foot and Joplin's is 30. For these trusses, that is not a lot. Wind load will be more important. I'd feel quite comfortable with 24" centers on the trusses for either wind or snow. I'm not going to analyze it though. I'm not that familiar with the mechanical properties of the wood and would have to make so many assumptions and estimates about your building techniques and actual loads and weights that my numbers would probably not be that valid anyway. You said you are going to make the building 30 feet, so just use all of them. It's more work but there is nothing wrong with building it too strong. You've already got the material.

Most building materials, sheathing, siding, plywood and such, comes in 4 foot widths. When sizing your building, it is good to build in sizes that accommodate this. Remember that you need to look at out-to-out dimensions, not centerline dimensions for some things. It is an easy mistake to make. Not that I've ever done it, but...... Also space your purlins, the studs in the walls. or whatever you are attaching to so you can attach the panelling or whatever you are using without extra trimming. A little forethought or trial fitting before you cut and nail can make life a lot easier.

I'm a little to the south of you. Last May, we had a straight line wind come through that took 36 feet of roof off a 12 foot x 60 foot shed. I'll be defensive and say that I did not build that shed. It was there when I moved here. As a structural engineer, the biggest design problems I had was not the major structural members. Those were easy. The connections were the challenge and that is where the failure here was. The construction was 2x4 purlins on 2 feet centers with a metal roof. The failure was that they used nails too short and smooth to attach the purlins to the rafters. 2-1/2" smooth nails through a 1-1/2" thick purlin does not hold a lot. When I replaced it, it was with 3-1/2" ring-shanked nails. So be serious when you attach your roof to the trusses and your trusses to the building framework. Use those rafter ties geosheets mentioned.

Those diagonal braces Pat mentioned are also a great idea. It helps stop racking which could cause your connectors, whether nails or screws, to work loose. And try not to drop those trusses so you don't loosen the connectors too much.

I built my coop (8'x 12') in the end of this shed. I'll include a shot that maybe shows you how I handled ventilation all around the top. That's hardware cloth over every opening. I've got plenty of overhang outside so rain is not a problem.

Editted for spelling and grammar.

 

[kathyinmo]

Thanks Jeremy and Ridgerunner. Your wise words are very helpful to me. I do intend to build as strong and sturdy as I possibly can, and your explanations are well received.
Thanks again!

Kathy

 

[jubylives]

Yes I'd agree with ridgerunner. You can buy these at Lowes to attach the trusses to the walls.:

The connector plates may look fragile but trust me they are in there good. I've had to remove them many times in my truss building years. They are not easy to remove as they are pressed in using alot of pressure. I used to train all new hires but after the plant closed I tossed most of it. I will still get that info I have on how to use these when I get home. I jumped on a PC in the break room at luch for some quick surfing. I work 12 hour shifts (7to 7) so it may not happen till the morning.

jeremy

 

[kathyinmo]

Thanks Jeremy!

 

[jubylives]

Ok brace yourself. Hdere are some links:

http://www.sbcindustry.com/bcsi.php

Scroll down and click the pdf files on the left. There are a lot of info on these. These are required to be sent with the trusses by truss manufacturers that are WTCA compliant. Don't worry about the text so much as the pictures. These give good illustrations as to what is done with trusses.

Some good referances:

http://www.chambers-house-build-it.com/ROOF.html

http://www.maplevalleytruss.com/truss_framing.htm

http://arkansasenergy.org/business_development/energy/files/Clearinghouse/ACF789F.pdf


Ok now that your head is spinning I will tell you that what you have is a simple truss. All you need to worry about is the bracing and the attaching the truss to the wall. Here is another connector that you can buy to attach the trusses to the walls:

What you want to avoid is the trusses falling like dominos. That is where the bracing comes in. With all of the trusses up you should have 2x4s running the length of the building. Attach the bracing to the king post or the center board going from the bottom of the truss to the peak. This along with what ever you are using for roofing. What are you going to use for roofing? That actually will bear on what to do next.

I will see if I can find something on tail scabs to help while I wait for what you plan on using for roofing as in wood sheathing with shingles or purlins and metal.

jeremy

 

[kathyinmo]

I'm not sure on the roofing yet. However, I did also get many sheets of corrugated galvanized metal roofing. They are about 16 feet long, I think. I will have to measure (I am at work now). So, I was thinking to use my 1/2 inch plywood that I have first, and then the metal. Would that work?

ETA: When I attach the bracing to the king post, am I going to go in a straight line, all the way the length of the build, or do I stagger them at different levels? (Or does that matter?)
Kathy

 

[MIKE555444]

I only have one suggestion.

MORE OVERHANG....

Unless you will have weather proof exterior walls then I would suggest more overhang to protect the side of your building. If I had it to do over again I would have given myself at least 18" of overhang. After ten years I have some rot on the bottom boards of my building.

 

[The LaMarr's]

Quote:
Howdy All!!

I used to work for a company that supplied Simpson Strong tie with machinery. All the new construction bracketry pictured in this thread were made on machinery that I installed at Simpson. If decide to use these brackets, they will definitely hold your building together (given that are installed properly). While I was on site at the Simpson plants, I was able to witness destructive testing on many of their products. It was amazing to see the difference in strength between standard wood construction and wood construction using bracketry. Some of the yielding forces were so great, that the testing was performed in a "blast" room. It had Lexan bullet proof windows to keep the flying debris under control. The improvement is so great that many cities along the hurricane zones in LA, TX, and FL have made it code on new contruction that Simpson products be used in construction. It calls oout Simpson by name, not a cheap competitor. Simpson takes great pride in what they do. In the years that I travelled for my company, I was in and out of several Simpson plants in the USA. I can tell you that it is not only a great company, but also they are great people to work with. I would not hesitate to spend a little extra on this if you are concerned about the joinery in your coop..

Thanks for listening to my rambling...

 

[jubylives]

Quote:
Yes the bracing will go the length of the building. It don't really matter where on the vertical member but I would suggest the center. Trusses are designed to work as a cohesive unit. Alone they flop and fall and can break. So the more bracing that connects them together the more of a unit they become. The other place I would suggest would be to run bracing along the bottom. That is not real necessary but it won't hurt. I couldn't find anything on the tail scabs for the added overhang but I still see what I can some up with. You will want at least a 12 inch over hang from the side of the coop. I will keep looking for info.

I use to know a Lamaar. You don't by chance have the name of John do you?

jeremy