I Beam for structural support

[MotorSeven]

MX, I hear ya. When I build a shed over my sawmill, I asked on a forum if I could clear span 30' with a 10x10 Poplar beam. Keep in mind this is only holding up a slanted tin roof. Many guys said it would not work and bow or sag. It's been up for 4 years and the beams crown is still showing a slight arch...^up...it has not moved a bit.

 

[shibaura_4043]

I wish the OP (shibaura_4043) would get back with us.

Last question I asked was about rafter sizes and spacing so we can kinda reverse-calculate what that roof is designed for and go from there.

Upon further looking at it, it appears as though the roof isnt designed to hold much load at all. I dont recall wether he ever said where he lived, or what kind of snow loads can be expected??? But....

It "looks" like they are 2x8's on a little more than 4' centers He said his barn was 30x30, so each rafter is spanning 15'. The load table I just looked at for a measly 20psf live load lists 2x8's (no. 1 grade) max span of only 14' AND thats on 24" centers:confused2: So that span is over that, and will less than half of the required rafters....

Usually never see rafters more than 2' centers. Any mroe than that and its truss territory....

As to the beam and what will or wont work....can help without more info. And even then, our ability to help is limited. I'd try to find out who built the building, and it may be worthwhile to have an engineer take a look. Cause right now...I'm not liking the rafter situation from what I can see.

Sorry for the delayed response, I have been very busy.... I had a gentlemen come out and take a look at the building and we have decided on a different approach. He thinks we can box up 2 30' sections of 8" cee purlin butted up to ridge and fabricate a couple of brackets to secure to the outside posts, additionally we will notch a few 2x6's or 2x8's trusses to add additional support underneath the purlin... he said he has done similar job this way and it worked well. The more I thought about it that large of an I beam was going to be a PITA to install, I think this way will be simpler and a bit more cost effective. Thanks to all for the input and suggestions... any comments on the new plan of action?

In regards to the rafters.. I havent measured but I would agree its close to 4ft centers admittedly this seems a little spacious hopefully the new trusses will take care of any potential weakness.