Engineering question on rafters

[River Lizard]

My current plan (which is buggin' me) for the rafters is using 2 x 4's but the span is an estimated 11' with no truss' (see coop topic for photos: My coop photos

I'm wondering if I need to re-think my design on the rafters to use 2 x 6's instead, I was trying to avoid the expense of the upgrade if I could. What do you all think? I can't build trusses because of head room issues, so it's got to be the weakest design with straight rafters.

My plan is to cover the roof with the same sheet metal roofing material as my carport is. I was planning on putting 1/4" plywood down first and then a layer of tar paper and then the metal roof.

We do get snow once in a while during the winter months, so there will be a chance of a snow load.

 

[Boondachs]

I built a 12 x 20 shed (with a barn style roof) using 2x4's, HOWEVER I used 1/2 ply as the sheathing material. 1/2" will give it more of a lateral load stability, but if you can tie yours together well then you should be fine. As far as the load goes, I dont have to worrie much due to the slope of mine, but I'd be a bit worried on a flatter roof. can you run a center support "wall" inside the coupe? If not I'd do the 2x6's, better safe then sorry. Hope this jiberish helps

 

[River Lizard]

Shawn,

I am going to divide the building into two sections, one being the nursery/supplies 6' x10' and the other the chicken coop area 10' x 10', so I'll have a wall just over 1/3 of the length. The pitch of my roof is to match my carport so it doesn't have much pitch as you can see by the photos. I'm not really worried about the 6' x 10' section since that's not too wide a foot print, but the 10' x 10' I'm a little concerned about since there will be no bracing on the rafters.

I've also considered raising the 10' x 10' section by about 14" in height to give us full head room at both sides of the room (currently with the height of the floor base, I won't be able to walk to the lower roof side without hitting my head on the rafters) I'll see if I can't post up a drawing of what I'm talking about doing if it's not clear enough for readers.
If I raise the chicken coop section 24" then I could add support braces to the rafters OR just switch to 2" x 6" on that section.

I've got to come up with a plan before next weekend because....one way or another.....I'll have some type of rafter/roof built next weekend!!!

 

[Boondachs]

AHHHHHHHHHHHHHHH I see now, I got the link to work.....hummmm let me have some more coffee and I'll get back to you

 

[Boondachs]

Hey Jeff, I am NO expert by any meens, but I would think that you would be fine with 2x4 rafters. Your slope seems to be fine for any snow you would get and since you plan on dividing it into two rooms, I would maybe place a single support close to the center of the large room, just for insurance. A support in the neighborhood of a 4x4 (like a jack post).
I do see what you are saying about head height though....looks like you will need to raise it abit so you dont cuse everytime you enter it.
The last time this area had a snow that would even come close to being a worrie was 1976! LOL hummm more coffee...more thinking

 

[Chicks_N_Horses]

Aww...If I had opened this thread 5 minutes sooner...LOL....my DH just walked out the door...He is a building/hardwood floor contractor. I'm sure he knew what to do....I sure don't

 

[Doormantnt]

Hello.

Looking at the pics I agree with ya'll...you have plenty of pitch to shed what little snowfall we have around here.

if you are going to divide the rooms, the largest "room" is going to be 10x10, you will be fine with 2 x 4's, but if that is the case I would use 1/2", not 1/4" ply, expessially if you "raise the roof",

with 2x4, with some blocking stud between, even in the 10 foot span there may still be some saging though...how bout a "lolly column" type brace

 

[Big Chicken Little]

I think in the long run you would be happier with a 2x6 roof. It might cost a little more but you would not have the sag problems that the 2x4 roof might have

 

[Intheswamp]

Quote:
I'm no contractor/builder but I see a possible issue with adding a post in the center and not having a support pier under the floor if the post was really to support things. ????

Ed

 

[Intheswamp]

I, too, think you'll be happier with a 2x6 roof structure. Also, in regards to your concern about headroom....are you going to do the "deep litter method"...that will decrease the headroom that much more.

Ed