Homemade trusses

[jimbob44]

I am considering making my own trusses and was wondering if anyone has did anything similar to what I have in mind.

The reasons for making my own are:
 1. No inspection code to meet where I live.
 2. The lumber is basicly free ( from my sawmill).

I plan on using preforated metal plates for the gussets just like the truss manufacturers use.
I know that plywood gussets have been used but general opinion seems to be that the metal makes a stronger joint.
Also, I know that it's been said that the preforated metal plate gussets need to be attached with a press rather than hammered in otherwise the integrity of the joint will be compromised.
However, I plan on using the following method that should make the joint actually stronger :
  Initially hammer the gussets in, using a solid flat piece of metal to prevent the hammer blows from distorting the gussets.
  Then covering each gusset with a piece of 3/8" flat metal stock, same size as the gusset, attached with 1/2" bolts through the whole thing ( 3/8" steel-gusset-joist member-gusset-3/8" steel) .
  This way the gussets will be compressed under a continous and evenly distributed pressure as well as the reinforcement that the steel plates add.
  Anyone see a reason why this method would not make a truss just as strong or stronger than a commercial truss ?
  Any other comments ?

[Robert_Flowers]

Jimbob
I have built trusses before ,the ones above my head are homemade all nave been plywood and glue they have been up for over ten years and are doing fine, built some back in 1980 or 81  for a garage on a new house still up no trouble.

I have a book  called Design for Glued Trusses from Midwest Plan Service in Ames,Iowa it's over 20years old but very good get one ifyou can.
[highlight]2. The lumber is basicly free ( from my sawmill). [/highlight]
I would worry about rough lumber for trusses it has to be dry if not  you are asking for trouble.

Have you every used metal gussets there are a pain in the a** not only do they stick you every time you pick them up they never stay in place ,you put them down tap with a hammer then the@#@# thing moves allways crooked.
3/8" steel plates and 1/2" bolts a lot of work  and a lot more weight.

What size trusses do you want?,
Are they going to be timber trussess ?
If they are then the steel plates and bolts would be a good idea, if they are going to be build out of 2xs then go with plywood.
a nail gun an a roller is a lot faster than a drill and socket wrench.

Hope this helps
Robert

[JRR]

I also like plywood vs the metal plates (that I'm familiar with) for homemade trusses.  The Simpson "connector plates" are not to be used in trusses ... if I remember the fine print correctly.

I would add screws. or nails. to the glued plywood.

[glenn-k]

I wouldn't worry about the wood being wet or rough - if wet was a problem Home Depot would have had to shut down a long time ago.  Cross shrinkage is a bit of a problem in some places - linear is not much usually.

I always use my own rough wood for anything I want.

The only thing I consider with wood from my sawmill is if it is good quality or not-  slightly rotten or once had bugs may go for rough siding - good stuff - small knots  I use for anything -similar to graded wood.  Grade it yourself-- you know what is good.

I assume you even reject graded commercial wood that is really no good.

[Okie_Bob]

In my humble opinion, some things are best left to the pros. Not that you can't do it yourself but, my time is worth something..I know Glenn, not much, but something!
I went to a local truss mfgr and am very glad I did. First, they sat down with me and designed the trusses exactly the way I wanted them. They didn't charge anything for this free engineering and then they printed engineered drawing for free. We changed out minds a few times and they never balked at designing them all over again.
We placed our order and was told they would be ready in 10 days. Exactly 10 days later they delivered the trusses and unloaded them on my lot, exactly where I wanted them, at no cost whatsoever. Total cost for trusses for 24' span on a building 50' long was less than $100 each. That may seem like a lot to some but, again, my time is worth something. By the time it would take to work up a bill of material, go get everything and carry it to my lot, then assemble the trusses and get help to move them around, it would have taken me at least a couple of months, working only on weekends.
The trusses were perfect, exact dimensions promised and everyone exactly the same. Made installation a snap in one half day!
I know the material cost is much less than what I paid for assembled trusses but, for me, it was the only way to go. And when I am ready for the trusses on our new cabin, I know exactly where I'll go to get them.
Just my opinion.
Okie Bob

[glenn-k]

There BoB - see --I told you your opinion had great value and we missed it.  

You are right - if you have something better to do it makes sense to use the local truss company.  I've even done it myself.

Speaking of local -- if you are in a small town area and have local businesses that haven't been forced to close by the big box stores - consider using them a bit more if they are within reason.  Many times your cost of fuel to go to the big box is more than the price difference at the local business.  Besides - the big box guys quite often gouge you on the small stuff to make up for prices you will check on the big stuff. :-/

Use it or lose it-----

BoB -- that nail wound on your forehead is festering up something fierce-- you better run and put a little peroxide on it-- what'd you use ---a nail gun?  Note is still there I see.

[Okie_Bob]

Glenn, all I had was a framing nailer...too cheap to buy a finish nailer.
So, how long before I can pull this dang 16d nail out of my head? I'm doing better...ain't I?
Okie Bob

[glenn-k]

Framing Nailer eh-- if it was the FR350 I'll bet that little bugger went into that skull a good 1/2 inch.  I've had 2 men shoot themselves in the hand with mine.  Penetration clear to the bone was not a problem.   :'(

How about --wear it until the paper falls off --- hopefully it will be stuck in your mind by then (get the point?) --and you'll remember to see what your friends are up too.  We need your good company and advice.  

See what happens when you forget to come home for a while?  

You done real good, BoB.

[NELSELGNE]

You can also nail trusses, as in the following plans:
http://www.ag.ndsu.nodak.edu/abeng/plans/5968.pdf

[glenn-k]

Lots of good information in plans like that.

Proven methods of doing things are always easier to learn from than having to figure them out for yourself.

[NELSELGNE]

5 pages of Rafter and Truss plans:
http://www.woodworkersworkshop.com/resources/index.php?cat=426

[PEG688]

jimbob44 What size building are you looking at doing ?  

 I ask because unless your looking at a wide building that has a open floor plan the width of the building , common rafters and ceiling joist / with collar ties may work just as well as a truss for ya .  

Truss are nice if wide and open are required. For most small building rafters with either a center partion or center beam can work just as well.

Always another way , well generally
 PEG

[bartholomew]

Jonsey built his own trusses for his place. He had two types, one bolt together and one nailed. The plans for his nailed truss are in the reference section...

http://www.countryplans.com/cgi-bin/yabb2/YaBB.pl?num=1115929745/0#0

Photos and discussion are on Jonsey's building blog...

http://users.tpg.com.au/jonsey/index.htm

[jimbob44]

Here's possibly a better idea for homemade trusses that should be just as strong or stronger than factory-built trusses.
This would be especially applicable for remote locations where factory-built trusses could not be trucked to.

One problem with factory trusses is that until they are in place, they are very fragile. In loading, unloading or installing, if they are subjected to lateral bending, the pressed in metal gussets may become loose or actually pull out.

On the other hand, a problem with a lot of homemade trusses is that usually plywood is used for the gussets and the gussets are attached using glue and a limited number of fasteners, usually medium size nails, or when bolts are used, even fewer. With considerably less fastening points than all the barbs on the factory metal gussets, the nails and/or bolts tend to apply pull to the members at just a limited number of points rather than a more complete 'grab' of the member like the barbs do. This makes for a joint that doesn't have the tensional strength of the factory gusset. If more nails are used, there is a tendency of the members to split. If more bolts are used, besides being more expensive, they would also weaken the attaching area of the member.

My idea is to use plywood gussets and attach them in the following manner. Using glue and two inexpensive 5/16" carriage-head bolts per member, attach the gussets to the members at each joint. (The purpose of the bolts is mainly to hold the gussets tightly to the members.) Then using an 18 ga. finishing nailer with 1&1/2" brads, cover the gusset area on both sides thoroughly. This method will provide a high number of attaching points, resulting in tensional strength similar to the factory metal gussets, and the small diameter of the brads will not split-stress the members like the larger nails would.
Readers, what do you think ?

[Dberry]

I wish there where some mechanical engineers that frequented this board.

I don't think the brad nails will do much.  Those carriage bolts may have a shear strength of 3000 pounds give or take.  A brad nail might have 25 pounds of shear strength (I googled it but didn't find anyone using brad nails for strength so that may be way off).   For my thinking though assuming those numbers are right, it would take 120 brad nails to equal 1 carriage bolt.  Plus the nails have very little pull out resistance vs. the carriage bolt that is clamping down with more than 3000 pounds.  If 2 carriage bolts aren't enough for your load, use more bolts....  The number of nails you would need to equal 1 bolt is staggering.  

I think brad nails to hold something in place while the glue sets is the best use for them.  Now... glue...  it's probably stronger than the wood, but you get into how strong the wood is...  Pine has roughly 1000 PSI shear strength...  so you would need 40 brads per sq in. of pine to equal the strength of the wood.

I'm not saying your idea won't work...  I'm not an engineer...  I just think the brad nails are eye candy from a structural point of view.  It's also possible that firing 100 brad nails into a joint might make the wood weaker.

BTW Those truss plates from the manufacturer are 1.5 to 2mm thick.  Twice as thick as a brad nail.  Nearly as thick as a 16D nail.  They function both as a bunch of fasteners as well as a gusset plate.  Pretty remarkable if you think about it.  They use a 50 ton press to install them.

Regards
Dan

[Bill(Guest)]

I like those Ag extension sites alot!
The one Nelselgne linked to was designed by engineers at the U of Maryland.  They show ya where, how many, and what sized nail to use, clinched no less.  I would be inclined to take their word, although my experience with engineers is not 100% [smiley=lipsrsealed.gif] If you're worried about splitting, blunting the point of the nail with a tap of your hammer usually does the trick, and/or you could predrill the holes.
For my money, my time might still be worth enough to justify buying the darned things.  Never do something you can hire done for less than it would cost in your time!  That's why I don't do masonry, drywall, or probably trusses.  Paying a pro for a couple days work vs. a year or so of my time is worth it! [smiley=happy.gif]

[cre90602]

If you can find Manhattan on the board I think he is an engineer if not hes preety dang close he is up on all codes

[glenn-k]

Manhattan is a contractor and eastern code inspector part time I think.

I believe he became disenchanted with me.  His last posting was a bit too rude.

[griff]

I've built  more than a few trusses.

Use good sized plywood gussets, lots of waterproof glue, and screws.

For strength, I'd put my trusses against any you can buy.

Some juristictions won't allow site built trusses. I am planning a tiny house in a city and I know I won't be allowed, so I'll use TJI's, since I want a loft space.

dave

[Dberry]

Judging by the number of truss plans offered by the agricultural extentions, apparently it was quite common for folks to build thier own until the last 20 years or so.

[griff]

We became "professionalized" about then.

dave

[John Raabe]

In the 1950's through the 70's site built trusses where common and there were many plans and guidelines for building these. Most building departments were comfortable with these predesigned solutions.

This is no longer the case for two reasons:
• Building Depts, in general, now want locally engineered solutions due to greater liability potential from earthquake, wind and disgruntled homeowners who are willing to sue local government. This is a basic CYA technique that has become more common in other areas of society as well.
• Computerized truss design programs in use by truss companies can quickly design and fabricate unusual or site specific trusses at (sometimes) lower cost than a generalized (and probably over-designed) owner-built truss. The engineering documentation for the Bldg Dept. is free gravy.

[glenn kangiser]

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