Acceptable deflection on a 16' ceiling span?

[STINEY]

I'm closing in on a plan to enclose, insulate, and heat my 150ish year old post & beam type barn. This is my shop, and will be much more useful when I can fire up the furnace without heating the great outdoors.

It does get cold here.

The plan is to replace the pair of sliders on the front with a pair of 10'x10' insulated overhead doors by framing up the openings, then the front can be sided with metal without the tracks or sliders to contend with.

Figuring out a ceiling has been a little trickier though. Rough idea is to hang nailers along the perimeter walls up high, and then use joist hangers to bridge the spans.

My problem is, I don't know what size of lumber to use? For the nailers or the joists.....the nailers will be spanning a good distance themselves, approx 10' between the upright posts. and 15' at the doors.

Was thinking 2x6 would be adequate, as this will only bear the load of the ceiling panels (thinking 1/4" osb), R20ish insulation, and some light fixtures.

Of course, budget is a concern. I want to use the lowest cost materials/methods, since this is basically building a building inside a building. I don't want something that fails prematurely though.

Anyone know if 2x6 are adequate, or if I can go even 2x4 on the joists?

Thanks!

 

[82_454_shorty]

I can't help you on the question, but I wanted to say, nice shop!

 

[RPH]

I give up with this virtual keyboard and edits!

 

[rieferman]

To be sure we understand, you're creating a lower ceiling, is that right? (as opposed to insulating the underside of the roof, you're dropping in a non-structural ceiling lower.. presumably because it's easier to heat)

edit: If I'm guessing correctly, I would say 2x6 should be alright based on my porch roof being made from them... and it holds plywood, shingles, and snow over a 12 foot span. They are spaced 16 OC. That doesn't mean my opinion or my porch are correct, just giving you a point of information.

AND, very nice barn. I'm a barn fan

 

[RPH]

Stupid iPhone keyboard double post.
Sorry

 

[RPH]

Check out www.northbridgesoftware.com
They have a free framing calculator and also supply a beam sizing one too. Have not explored these yet but do look interesting. Cost for the beam sizing is $125.00.QUOTE]

 

[RPH]

Do like the barn though. I have a 32' x 45' one and love the look of the old beams.

 

[STINEY]

Thanks guys.

Yes, I am basically adding a ceiling, have no need or want to heat all the way to the roof, its 30' up there.

I couldn't get that northbridges link to work..... ?

Rieferman, I do a lot of lurking/searching/reading on here. I've quite enjoyed following along on your barn resurrection, nice work. You & I have done a lot of the same work as far as jacking up and stabilizing old barns are concerned, this one I jacked up the front approx 11" all the way across. Dug down and poured footings for the verticle posts, there was very little remaining of the horizontal sill beams. Fun stuff!

 

[6768rogues]

With no storage upstairs, a deflection of 1/180 is acceptable. For storage (building a floor) a deflection of 1/360 should be used. Find a span table and look up the lumber size. Span tables specify the species and grade of wood, it makes a big difference. Different regions have different species in stock at a good price. Find out what species and grade are available at a decent cost, look it up on the span table, and go for it.

 

[framer]

2x6s two ft centers up to 17 ft span with 1 or 2 2x6 stiff backs on top wil work.
Deflection may be 3/4 inch is acceptable.Use no.2 yellow pine. Nothing but 40yrs. hands on experience . Love that barn. good luck

 

[STINEY]

2x6s two ft centers up to 17 ft span with 1 or 2 2x6 stiff backs on top wil work.
Deflection may be 3/4 inch is acceptable.Use no.2 yellow pine. Nothing but 40yrs. hands on experience . Love that barn. good luck

By "stiff-back" do you mean 2x6s fastened to the top of the ceiling joices, running perpendicular to the joices? I'm not familiar with the term stiff-backs....

 

[framer]

Yes you have it right. Nail a 2x4 flat across joists then nail 2x6 on edge to it
Stiffens ceiling. Lap any joint with 6 to 8 ft scab. Framer

 

[RPH]

Try the link again. Works here from Germany.

 

[BooUrns!]

Maybe instead of trying to scab up some light framing, just work on reducing air loss. Look into creating an air barrier on the inside of the shop, sort of like tenting or hoarding the inside. It won't be warm as a house but it will likely be easier to do and less prone to structural failure.
If you're determined to go ahead and frame into the existing structure, it would probably be best to ask someone with more construction expertise to look at your idea. You're looking at putting something above your head, you should make sure it's not going to come down on you.

You've got advice here ranging from technical knowledge to years of experience coming at you but no one has seen the structure personally so they can't guarantee what will work and be safe to occupy.

There are simple joist span tables that could answer your question regarding the lumber sizing. It's not really a question of how much deflection is acceptable, it's a matter of what is the right way to build it. Don't take short cuts to save a buck.

 

[STINEY]

.....

 

[rieferman]

I dunno... To me, it's a basic loft structure inside a barn, this isn't rocket science or a need for major over-engineering. I've seen so many 2x6, 2x8, and 2x10 lofts holding tons of weight, and even people etc. This one is just holding some insulation and OSB. Hell, the roofs on store bought sheds hold more weight and are made from 2x4's in many cases. In this case, short spans and little weight. I just checked some basic calculators, and it looks as though 2x6 will be fine for the planned span. Personally, I'd use the 2x6's and call it a day. If really concerned for any reason, go 2x8's. But I don't think this is a situation where engineers, inspectors, architects, i-beams etc. etc. etc. are needed.

edit: 2x6's for the 10 foot spans I mean. For the 15 foot span area, I'd go 2x8.

(disclaimer: I'm not a builder, so this is just my opinion. No flames accepted )

Stiney wrote:

Rieferman, I do a lot of lurking/searching/reading on here. I've quite enjoyed following along on your barn resurrection, nice work. You & I have done a lot of the same work as far as jacking up and stabilizing old barns are concerned, this one I jacked up the front approx 11" all the way across. Dug down and poured footings for the verticle posts, there was very little remaining of the horizontal sill beams. Fun stuff!

Awesome! You're building (and your work) are a lot bigger than what I've accomplished, but I love to hear about stuff like that. You should do a build thread over in the gallery forum!

 

[STINEY]

We see this the same way, no rocket science required. I'd say our projects are pretty close to the same on the amount of work, you slaved your **** off on your barn, and it shows. Mine is just bigger physically.

I'll work on gathering pictures and may do a build thread. Lots of the pictures will be scans, so be warned...

 

[STINEY]

Some more pictures to better illustrate what I'm working with here. Basically I want to lower the "ceiling" approx 4' to the level of the main sliding door "headers".

Its a long way to the roof. Pretty much rules out spray foam on the roof....