lean to for extra storage

roxynoodle · Oct 31, 2006

I will probably be pricing out trusses this week. Of course it is possible I could make them too.

I replaced a lowered cardboard tile ceiling in my house with drywall. It has what appeared to be a very strong 2x4 structure. I tested it by hanging from it in various places. I decided that if it could all hold me, it could hold drywall. But, I think all of you are right. I sure wouldn't use a 16' 2x6 as scaffolding. It would sag.

randy41 · Oct 31, 2006

except that if your weight was spread out over several of them as the weight on your roof would be because of the purlins then there would be no sag. i assume the 2x6 is on edge not flat which would make balancing the toughest part.

i have been inspired somewhat by your project to think about building a shed garage attached to my now unused chicken house (my chickens live in a portable house).

MikeD74T · Oct 31, 2006

Roxynoodle, Here's truss plans. Free Truss Plans MikeD74T

ovrszd · Oct 31, 2006

MikeD74T said:
Roxynoodle, Here's truss plans. Free Truss Plans MikeD74T

Isn't that an awesome website!!! I got some building plans from there also!!!

EddieWalker · Oct 31, 2006

randy41 said:
except that if your weight was spread out over several of them as the weight on your roof would be because of the purlins then there would be no sag. i assume the 2x6 is on edge not flat which would make balancing the toughest part.

Randy,

The problem with this is that we're not even considering any sort of loads on the 2x6. In order to support a load, the structure must have a certain level of strength to begin with. Spanning 16 feet with a 2x6 by itself will sag over a short period of time. Adding purlins to the weight will just speed up the time it begins to fail.

You haven't made the beam any stronger with the additional weight, and in fact, you have made it weaker. Purlins will not add any structural strength to an undersized beam.

Purlins will help distribute a "LOAD" that is on top of the roof over all the supporting beams or truss's. The same thing is true with sheeting or decking. But it always comes back to the integrity of your structure as to what it will support.

Eddie

roxynoodle · Oct 31, 2006

I think y'all are right and it's too big of a span for anything but trusses. A triangle is the strongest geometric structure, which is why you see them on bridges. I don't really want extra support beams in the middle of it because they would just be something to hit with a trailer or tractor.

randy41 · Oct 31, 2006

EddieWalker said:
Randy,

The problem with this is that we're not even considering any sort of loads on the 2x6. In order to support a load, the structure must have a certain level of strength to begin with. Spanning 16 feet with a 2x6 by itself will sag over a short period of time. Adding purlins to the weight will just speed up the time it begins to fail.

You haven't made the beam any stronger with the additional weight, and in fact, you have made it weaker. Purlins will not add any structural strength to an undersized beam.

Purlins will help distribute a "LOAD" that is on top of the roof over all the supporting beams or truss's. The same thing is true with sheeting or decking. But it always comes back to the integrity of your structure as to what it will support.

Eddie

seems like the only loads to consider are the weight of the purlins and roofing material and the potential weight of any snow. i think using trusses is overkill and maybe 2x6's are not enough but spacing them closer than 2' or using 2x8's would be a lot cheaper than trusses.

EddieWalker · Oct 31, 2006

Just to through another option out there, but can you put in some posts at the midway point?

I'm assuming that you will put in some posts with a header type beam at the far side away from the building. Spacing is up to you, but 12 feet is pretty stnandard. You have two ways to top off the posts to support your truss's or beams. One is to double up a 2x8 with half inch plywood between it. This makes a very strong beam. The other option is to put a single 2x8 on either side of the post.

You will rest your beam on top of these headers.

Now at the halfway point out from your posts, you put in another post. At the top of this post you do the same thing as you did on your end posts.

Now you only have about an 8 foot span, which should be fine for a single 2x6 every 4 feet apart.

With a 4 foot spacing, you can use 2x4's on there flat side for purlins.

This will save you as much money as possible, but still give you the same open area. The only drawback is the extra posts.

Eddie

roxynoodle · Oct 31, 2006

I built my pole barn using 2x12s on each side of the posts to rest the trusses on. I was thinking 2x10s to rest the 2x6s on. I could put extra posts in the middle, but that would affect storage of trailers, tractors etc. The closer together they can be parked, the more I could fit in there. The trailer is a 16' and more than 7' wide. The tractor has the wheels set out at 84" apart. I was also hoping to squeeze in the manure spreader behind the tractor. So, I could put posts in halfway but it might be tight for parking in there.

randy41 · Oct 31, 2006

i have the original Pole and Post Buildings Design and Construction Handbook. Seems like theres a newer version available for $14. It contains tables that tell you what size lumber to use for different span and load situations. Mine has a snow load map and a wind load map. It discusses poles, girders, rafters and joists.

Building Construction Publications: NRAES-1

with a little bit of work on a calculator you can figure out what you really need. I also have one of their publications that is about building your own trusses.

MWPS: MidWest Plan Service, A Foundation of Knowledge for Agriculture

theres some more interesting books including the truss one.