any carpenters?..construction question

[dpcutter]

I'm changing around my workshop area, and want to span the depth of my shop which is 23' 3" deep withouth and floor posts. I was thinking of making my own trusses, out of #2 grade 2x4 stock. I was thinking of making a flat truss, with a triange/web design in center with a 2x4 on top and bottom as the chords. The top and bottom chords I will turn on edge for additional strength. Main question, can the top and bottom chords(the 2x4's on edge) be spliced together?? I want to span almost 24', can I simply butt up the 12' length 2x4's to make a total length of 24'? I was thinking of using a metal joinery plate on each side of the splice on top and bottom, and also use plywood over the spliced area, 2' to each side of splice. If this will work, do the splice on top and bottom have to be staggered?? if so, how far, or can I get away without staggering them??? Thanks guys!!

 

[landrvrnut22]

Here's a stupid thought. Before you go making your own, why don't you go to the local lumber yard, and see how much they are. I can guaruntee the price to buy the trusses, and have them delivered to your door is way cheaper then you buying the lumber, and trying to build them your self.

They will also be designed by an engineer, and if they fail, the engineer would be responsible. If you build them yourself, and they fail, its on your head.

Also, if you have any kind of inspection done, the inspector will ask for the stamped drawings. When you tell him you built them yourself, he will laugh at you, and fail the inspection.

Only trusses I have built myself were for a 8x12 storage shed.

 

[volks-man]

I'm changing around my workshop area, and want to span the depth of my shop which is 23' 3" deep withouth and floor posts. I was thinking of making my own trusses, out of #2 grade 2x4 stock. I was thinking of making a flat truss, with a triange/web design in center with a 2x4 on top and bottom as the chords. The top and bottom chords I will turn on edge for additional strength. Main question, can the top and bottom chords(the 2x4's on edge) be spliced together?? I want to span almost 24', can I simply butt up the 12' length 2x4's to make a total length of 24'? I was thinking of using a metal joinery plate on each side of the splice on top and bottom, and also use plywood over the spliced area, 2' to each side of splice. If this will work, do the splice on top and bottom have to be staggered?? if so, how far, or can I get away without staggering them??? Thanks guys!!

i am reading this as a roof truss.(?)

main question: short answer is yes. trusses frequently have butts in them.

2nd question: they wil be staggered already. the bottom chord is horizontal while the top chord is on a slope. they will not line up vertically.

comments:
1: your building inspector will want to see an engineered drawing of the trusses with an engineers stamp on them.
2: trusses are designed to carry specific live, dead, snow, and wind loads. the webbing is placed to maximize the strength of the roof system. it would be hard to calculate what you would need without the proper tables.
3: layout is important. most trusses are designed to be used on a '24" on center' layout. depending on the loads you will encounter you may need to utilize a 19.2 layout with 2x4 construction.
4: if you are still thinking about building your own trusses after reading above you will need to make a full size jig (in shape of the truss) so that they will all end up the same.

 

[MATTYB11]

I also suggest pricing out engineered trusses at a local lumber yard. 23' is a prety big span to be making up your own trusses.

 

[ehgauss]

I had the misfortune to be able to buy enough 2x4s that a neighbor had left over from a construction project at too good a price to pass up. That enabled me to build my own 24' trusses for a garage I built at a cost that was favorable compared to prefabricated trusses, but it was a lot of work. Also, as an engineer, I found my old statics textbook that reminded me how to calculate the load on each of the truss members and joints, considering the structural and snow loads. I also designed in and included a lift beam setting on the lower chord of the trusses the length of the garage. I've lifted engines, etc. from the beam with no trouble. I used a double W +1 configuration and fishplated each joint with 1/2" plywood, nailed and glued. You would need a special press to install the metal plates used in the store bought trusses. It's pretty low level engineering but tedious to do the calculations necessary to get the right design, but unless you're comfortable doing it right, and doing a lot of work, you're certainly better off (and maybe not much more expensive, if at all) buying them ready made to your requirements.

 

[ehgauss]

I forgot to mention that I did include the truss calculations with the application for a building permit. The building inspector's comment was "If you can do those calculations yourself, I'm not going to bother checking" (beyond verifying I was using the correct values for snow, wind, and structural loads).

 

[trimmmed]

I'm changing around my workshop area, and want to span the depth of my shop which is 23' 3" deep withouth and floor posts. I was thinking of making my own trusses, out of #2 grade 2x4 stock. I was thinking of making a flat truss, with a triange/web design in center with a 2x4 on top and bottom as the chords. The top and bottom chords I will turn on edge for additional strength. Main question, can the top and bottom chords(the 2x4's on edge) be spliced together?? I want to span almost 24', can I simply butt up the 12' length 2x4's to make a total length of 24'? I was thinking of using a metal joinery plate on each side of the splice on top and bottom, and also use plywood over the spliced area, 2' to each side of splice. If this will work, do the splice on top and bottom have to be staggered?? if so, how far, or can I get away without staggering them??? Thanks guys!!

Yes the chords can be spliced. I would defintely stagger them differently on top and bottom.

What metal joinery plate are you going to use? Are these floor trusses or ceiling trusses? They will probably need to be 20" deep or so.

 

[Mkarlson]

I've built a few trusses and would reconmend the making of a jig or building one check it for size and correct slope your looking for and build the others on top of the first. Those hardware store beat in steel plates are not worth the time and money it takes to use them. In a truss factory hydraulic stamping machine are used to install them at home a hammer and block of wood can be used but not with great success. I'd just use plywood gussets at each joint.

landrvrnut22 is correct...you can sometimes find the trusses pretty cheap at menards or lowes.

 

[volks-man]

forgot to mention....

although it could be very dishonest you could contact a truss builder with your measurements and get a quote. the quote will be accompanied by a fairly detailed drawing of your proposed trusses.

the catch is that it would not be right to ask for a quote if you have no intention to buy from them.

maybe i should not have mentioned it?

 

[dpcutter]

I want to make a flat trusses, so that the top and bottom chords are parallel to each other. I want to turn the 2x4 on edge for more strength, and cut 2x4's at 45 degree angles to form the web pattern in between the top and bottom chords. I have looked at several images of flat trusses on the internet and they look very simple to construct. MAIN QUESTION: will it work if I butt the two chords together and splice them together to form a total of 24'.....two 2x4x12 foot sections butted together and spiced at the center point to create the 24 feet. Home Depot sells metal joinery plates. I was thinking of using them on each side of the splice, and also cover the whole side of truss where splice is located with a 4 foot length of plywood, 2 feet each direction beyond spliced areas....is it ok to have the splices lined up on both top and bottom??... btw, this is a side project, no building permit or inspectors just a backyard LOW BUDGET project....thanks guys!!

 

[CUCV]

I am currently building a 28' x 32' garage with an apartment above. I bought floor truss for $2600. I went with 18" tall trusses at 16" OC because the building was getting to tall but I could have saved money going with a taller truss at 24"OC. This truss company has a bunch of designs online which could help you out.

http://www.wsitruss.com/Prod_Frame.asp?Truss=F24

 

[volks-man]

I want to make a flat trusses, so that the top and bottom chords are parallel to each other. I want to turn the 2x4 on edge for more strength, and cut 2x4's at 45 degree angles to form the web pattern in between the top and bottom chords. I have looked at several images of flat trusses on the internet and they look very simple to construct. MAIN QUESTION: will it work if I butt the two chords together and splice them together to form a total of 24'.....two 2x4x12 foot sections butted together and spiced at the center point to create the 24 feet. Home Depot sells metal joinery plates. I was thinking of using them on each side of the splice, and also cover the whole side of truss where splice is located with a 4 foot length of plywood, 2 feet each direction beyond spliced areas....is it ok to have the splices lined up on both top and bottom??... btw, this is a side project, no building permit or inspectors just a backyard LOW BUDGET project....thanks guys!!

why didn't you say so?

forget everything i said.

i know nothing about flat (floor?) trusses. just roof trusses.

if i had to guess i would go with the other guys and say stagger the joints.

good luck.

 

[dpcutter]

I want to build a flat roof truss, my pitch will be made by my difference in front and rear wall heights. I have a shed roof. The current difference in height is only 2 feet, I'm going to make the front wall to rear wall a height difference of 3 feet six inches. I figured the flat trusses would be very simple to build...was really only concerned with depth of truss with #2 2x4 stock, and if it's ok to splice the chords, and do they need to be staggered or can the be aligned on top and bottom?? I will have about a 9 degree pitch with aluminum metal roof material which has been on there already for years so I know the material will work. I just want to make sure the trusses are strong enough if I splice the top and bottom chords, and what the overall depth should be...?? thanks guys

 

[redprospector]

A splice is the weakest point in any truss. In my opinion they must be staggered. I've built trusses for quite a few projects (years ago), and alway's tried to avoid a splice in the center of the span. That was on a regular roof truss though, not a flat roof truss.
We used to call a "flat roof/floor truss" a king beam.

Andy

 

[dpcutter]

The truss will be of flat construction style, but the roof will have a pitch to it. The front wall will be 3'6" taller then the rear wall. I just figured it will be easier to construct them using a simple flat truss design much like the ones used on floors, but also used on roofs. I will have my pitch by my difference in wall heights, so in essence it won't have the weight on it that a typical flat truss would normally have....

 

[ropensaddle]

I want to build a flat roof truss, my pitch will be made by my difference in front and rear wall heights. I have a shed roof. The current difference in height is only 2 feet, I'm going to make the front wall to rear wall a height difference of 3 feet six inches. I figured the flat trusses would be very simple to build...was really only concerned with depth of truss with #2 2x4 stock, and if it's ok to splice the chords, and do they need to be staggered or can the be aligned on top and bottom?? I will have about a 9 degree pitch with aluminum metal roof material which has been on there already for years so I know the material will work. I just want to make sure the trusses are strong enough if I splice the top and bottom chords, and what the overall depth should be...?? thanks guys

Hmmm I am not exactly a carpenter but what I am seeing is
a semi flat roof using 2+4 in a snow load area. I am wondering
if they will be enough in that long of span to support the load
of all that snow but I may be missing something.

 

[Metals406]

The truss will be of flat construction style, but the roof will have a pitch to it. The front wall will be 3'6" taller then the rear wall. I just figured it will be easier to construct them using a simple flat truss design much like the ones used on floors, but also used on roofs. I will have my pitch by my difference in wall heights, so in essence it won't have the weight on it that a typical flat truss would normally have....

What you are wanting to build is called a parallel cord truss... And for your application, I'd say BCI's or TJI's would be better, faster, less time consuming and lighter. Call your local lumber yard for the span charts for the joists... Stiffening the webs of the joists with plywood will also allow for a greater span/load.

 

[teacherman]

Here's a stupid thought. Before you go making your own, why don't you go to the local lumber yard, and see how much they are. I can guaruntee the price to buy the trusses, and have them delivered to your door is way cheaper then you buying the lumber, and trying to build them your self.

They will also be designed by an engineer, and if they fail, the engineer would be responsible. If you build them yourself, and they fail, its on your head.

Also, if you have any kind of inspection done, the inspector will ask for the stamped drawings. When you tell him you built them yourself, he will laugh at you, and fail the inspection.

Only trusses I have built myself were for a 8x12 storage shed.

Yes, this is true. If you wanna build yer own, Fine Homebuilding had an article on truss building a while back. The main thing is that the center of the angled web pieces and the chords have to meet at one point for the truss to work. Do sum research. Otherwise, if you want it to be bomber, make a glue lam of flat 2X6 lumber, staggered joints, 10-15 boards tall. It will be bomber, but again, research the specs and procedures for prestressing the beams. Good luck!

 

[west county]

your going to want to use something other than white wood studs for trusses. Yellow pine or even typ would work much better. The metal mender plates from Home depot are not need if you are going to use plywood at ALL joints. The menders are installed with a high pressure press at the truss shop and very hard to install on site without the press. Just plywood both sides of the splices with a air powered large staple gun with many more staples than you think you need and it will work. Still after all I have said, I would go and have the truss shop build them, it will be stronger, safer, easer, and cheaper

 

[mtgrs737]

Truss building lumber yards use a computer program to design and spec materail for their trusses. The lumber used is most likely spec'd out at a certain minimum tensil strength for the truss to carry the load it was designed for. Most truss building lumber comes from old growth Canadian forests as our forests have been harvested of the tight ringed slow growing old growth timber needed to build strong trusses. We re-planted with faster growning pulp wood type trees ment for the paper industry and that is why a two by four is so light compared to the old growth lumber of our fathers generation. But thats progess! Right?