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

[kathyinmo]

I got some free trusses, tearing down buildings. I have 24 of them, and they are 126 inches long. My question is: how wide will I make my build? The full 126 inches, or is that part of an overhang? Another question, how far apart do I place them?
Thanks alot!

 

[Suburban chick farmer 09]

What you have are trusses. I would put a one foot overhang on each side of the building. That way you can put vented soffit in. It will help with ventilation. Don't put them any further apart than 2 foot. It looks like a lower pitched truss so if you're not planning on building a huge coop, I would put them on 16 inch centers.

 

[kathyinmo]

OK, I changed the topic from rafters to trusses. So, what you are saying is that the build should be 1 foot less on each side (so 126" minus 24" = 102") or 8' 6" ? Can I make it long? Like 40 feet long?

Do I have this correct... I just lay these on top of the frame, and then add the plywood on top to prep for the roofing?

 

[Suburban chick farmer 09]

Quote:
The building should be 21 inches shorter than the truss. That way, when you add your 2x6 gutter board your finish overhang will be 1 foot on each side. Yes you can make the building 40 foot long. You will have to lay the trusses out on 2 foot centers though.

 

[Suburban chick farmer 09]

Quote:
Set your first truss flush with the framing on the end of the building. After this truss is set, you will need to plumb it (level) and brace it off to something solid. With the first truss braced off and plumb, you can now use this truss to brace the rest.

 

[kathyinmo]

Thanks for your help, Tim. I looked at your coop .... it is lovely! Hey, you are near me.... come on over and help! ha

Actually, I am still busy cleaning lumber. I have lots to do! I think it is worth the extra effort, to not pay for the expensive lumber.

By the way, what is the difference in trusses and rafters?

Thanks again!
Kathy

 

[patandchickens]

Please be careful with those trusses, they look "less than sturdily constructed" and no longer in quite the best shape either. I would recommend taking the time to cut some gussets out of 1/2"+ plywood to reinforce all the joints. Nail them on top of the existing cheesy little join plates. Otherwise you may find pieces of your roof leaving in a strong wind.

Yes, you do need roof overhang to have a 'healthy' long-lived building (and it's handy for ventilation too), I would recommend 1-2' of overhang on each side. So your walls will have to be several feet closer together than the length of the truss.

I would second the recommendation to run them 16" o.c. rather than 24", although it depends a bit on what kind of roofing you are planning and how much snow and wind you get. Whatever regrets you have from building things too weebly are usually MUCH MUCH larger than any regrets generated by building things a little stronger than maybe strictly necessary

Once your walls are erected (and braced!), put the trusses up by lifting them *upside down*, one corner up on one wall then the other corner up on the other wall; then a helper and a couple long posts and/or piece of rope will help you "flip" the truss so it is correctly pointy-end-up. It is highly helpful if you can tack a long vertical 2x4 along the midline of the end wall, as a "stop" for that first (end) truss and to give you something to temporarily attach it to so it stays plumb and upright til you have more trusses up and they can be attached and hold each other in position. Successive trusses get tacked to that first one, once they are in correct position and alignment, and once you have them all up the roof purlins (or sheathing) will hold them together.

It is a real good idea, especially for a building that is longish in relation to its width, to put in diagonal braces as well, nailed to the inside (underside) of the upper portions of the truss. This discourages the roof from keeling over like a line of dominos.

If you have not worked with trusses before (btw, to answer your Q, a truss is a usually-triangular multidimensional structure of multiple members joined together, that supports itself rigidly across the whole span from one wall to the other; a rafter is a single piece of lumber that is supported on the wall's top plate at one end and on the ridge beam at its other end) it would be *highly* worth picking up a book on building barns, sheds, garages, houses, whatever you can find at your local bookstore or library that has a section on dealing with trusses. There are a number of tricks that can make your life easier, also there are certain things it's important to do or not do in order to get a building that reliably stays upright and together

Good luck, have fun,

Pat

 

[kathyinmo]

Thanks Pat. I will do as you suggest, and add on plywood reinforcements at the joints. I will also do my homework, and research the use of trusses. I appreciate all suggestions!
Kathy

 

[Suburban chick farmer 09]

You don't need to add anything to the joints of the trusses. The gussets on the trusses you have were stamped on at the factory.

 

[Lensters]

An electrical engineer's opinion after consulting a couple of mechanical engineers...

The trusses look like they are in fine shape as long as that is remnants of bees or birds nests on the end (as opposed to ant or termite damage). The trusses were designed to be flush with the edge of the building, but with your nice close up it appears that you would be safe with up to 10" overhang. Since they are built out of 2x4s on essentially a 5' span and looking at 35lbs/sqft snow load for your area (a complete guess) they should be placed at most on 18" centers. You will need to run a set of brace boards to keep the bottom, middle from bowing as well as some diagonal braces as Pat mentioned.

This is with the idea of using plywood sheeting instead of purlins.