Architectural-Structural Questions

[SteveS]

Thanks a LOT for the drawing..."a pic is worth a thousand words!"

The ribbons strip/joist design looks easy enough. One more time though: can I span the ENTIRE 26' and expect it to actually hold some weight? Are the wall studs (2x4's) enough to take the load?

I intend to finish the interior walls with hardwood (I already have the lumber milling in process). My plan was to simply get rolls of insulation and staple them in and nail/tack the hardwood boards directly to the 2x4's via an angled design. (instead of running them parallel or perpendicular to the floor). Are they any flaws in this method? What is the fire-stops you are speaking of?

Many thanks once again!

[Danford C Jennings]

Steve,

You're welcome.

One more time though: can I span the ENTIRE 26' and expect it to actually hold some weight? One more time; yes but you still need to check with your building department for the schedule.

Are the wall studs (2x4's) enough to take the load? Well it's my understanding from your first post that the wall studs are 2 x 6, even if they are 2 x 4 it will work. Balloon framing was very common in Pre WWII residential construction.

I intend to finish the interior walls with hardwood (I already have the lumber milling in process). My plan was to simply get rolls of insulation and staple them in and nail/tack the hardwood boards directly to the 2x4's via an angled design. (instead of running them parallel or perpendicular to the floor). Are they any flaws in this method? Use faced insulation and 6 mill visquine for a vapor barrier, then apply your inside wall sheating.

What is the fire-stops you are speaking of? In a balloon framed structure the stud bays are literally chimneys, so you have to nail in "fire stops" between the studs. Use the same nominal lumber for the stops as your studs, again you'll need to check with your building department, as I recall fire stops are every 4' in a ballooned frame structure.

Dano

[SteveS]

I stand corrected, my uprights (studs) ARE indeed 2x6's as first mentioned. I checked on Georgia Pacific's web site for I-Beams. (some suggested I may need them to span a 26' width. Would there be any advantage to using these instead of 2x6's or 2x8' other than getting away with larger centers?

I was not able to find if you told me what size joist I should use. How do they connect since I doubt I will find 26' lumber. They use plates like the truss structures?

When you say, "check with your buidling department" I am not sure what this means? I make furniture mostly, so all these building/structure issues are all new to me! :o

Thanks mucho!

[Lou_williams]

I don't think even a 2x12 standard timber would go 26 ft. The I beams are engineered with a glue laminated 2x4 on the top and bottom, and a plywood section glued between the 2x's. They would be made to order and would span the total width. There is no way to join standard timbers in the middle without a load bearning wall structure or steel beam down the middle of the structure.

When you have a building built in most areas you need the local county building department inspect the building to ensure that it is built to code and for that most of the time a building permit is requred. It protects you if you are doing any structureal changes to a building. Without a permit you might have a hard time getting an insureance company to pay damages in case of fire or other loss.

With no or little knowledge of structural engineering you might want to check with a professiona engineer. They cost a bit of money but then you will know that when it is built it is safe for you and others.

[TDHofstetter]

I'm gonna drag this thing back to the left side so we can all start over. :)

Especially me - somehow I got the impression that the PEAK of the roof was 16' and you wanted to be able to support decking inside the trusses. Never mind me.

OK, Steve, lessee if I've got all this straight. You do indeed, as seen from the pics, have "W"-style trusses built up of 2x4 lumber. Those trusses are perched atop what appears to be a 16'-high stud wall built of 2x6 lumber, and the roof pitch appears to be about 5:12 (not that the roof pitch makes any difference, but I hadda say something to keep from feeling dumb :) ).

On one end of the building is a rollup door just about 14' high and 16' long.

You propose to build a floor 10' above the existing floor so as to add a second level to this building for storage. You want this floor to be unsupported in the middle so as to not interfere with the rollup. Therefore, you want a 26' clear span in the floor joists for this second level.

Several questions & observations come to mind at this point.

As pointed out before by others, a 10' high 2nd floor would leave you with only "ducking" room in the second level unless you're significantly shorter than 6' tall.

If this deck is built as proposed with a clear span of 26', the rollup would not be interfered with in terms of width - but are you positive you want to split its height with a second floor? As I see it, that rollup would open about 4' high in the second level when fully open. This could be cause for serious safety concerns unless you erect a guardrail at the rollup end.

I'm rather sure your existing 2x6 walls would support a considerable additional load in the form of your upper deck, and that Dano's drawing would be a good way to accomplish that. I'd like to disagree with him on one point, though - I believe you'd be better served by attaching the ledger to the FACES of the studs rather than letting it into notches. As Dano pointed out, the joists would be nailed to the studs supporting them as well as being supported by the ledger. (Edit - reworded for better clarity)

So - we have our ledgers attached to our studs. Next come the joists and the real issue. You can, in fact, buy 26' lengths of 2x12 for those joists - and you could build a deck on such joists. It'd probably even hold almost anything you chose to stand on it. It WOULD, however, feel rather like a diving board when you walked on it. You would see an enormous deflection in the middle as weight was added to the second level. It's that 26' clear span that's the killer.

You'd be forced to put your joists on 16" centers to match the stud walls - one joist per stud, nailed to the side of the stud. You couldn't add stiffness by setting the joists on 12" centers because... there's NOTHING to NAIL them to! Only one in ever 4' would have a stud to attach to. The only way around THAT issue would be to build a secondary 2x4 wall immediately inside the 2x6 wall - just to support the overhead deck. With THAT approach, you could set your upper level joists on 12" centers and thereby add a lot of stiffness.

Even at that, though, the second floor would be pretty bouncy of you used conventional lumber. No matter what you did, even installing DOUBLE 12" joists on 12" centers, you'd still feel a disconcerting movement in the second level if you used conventional lumber. To stiffen the floor further, engineered floor joists would be my preferential solution. You could use the plywood-cored I-beam construction that's becoming so common, you could use steel "W" floor trusses (the most rigid)...

...they're shaped like this:

_____________
WWWWWWWW

...or you could use shopbuilt wooden "W" floor trusses. They're built the same way as the steel ones, by sandwiching a series of 2x4 angle braces between top and bottom chords of 2x4 lumber. If built right, they can be amazingly strong and rigid.

You could, in my opinion, avoid a lot of this trouble by adding support at both sides of the rollup, though, in the form of a post-and-beam structure. That'd give you a 16' clear span for the door, while drastically lessening the need for mongo floor joists. A 16' clear span isn't nearly as difficult to work with as is a 26' span.

The support posts need not interfere unduly with your work area. My own shop is punctuated at 12' intervals by 8"x8" posts, and instead of being an inconvenience they actually serve me well as great places to hang stuff. The overhead beams, too, provide plenty of additional storage for things like sawbands and chains... I even store some long stock atop the beams, nestled among the joists. Long lumber, pipe, even a plastic cargo sled hide themselves harmlessly out of the way up there... requiring ZERO storage space on any floor.

TAG - you're IT... :)

-- Tim --

Argue for your limitations,
and sure enough - they're yours.
- Richard Bach -

[Lou_williams]

Tim,

I like yoru approach, One major advantage of the I beam trusses, they are light enough to handle a 26 footer with one person. The W trusses at that lenght would need lot of help to put in place. The post and beam would be the way I would go if the inside posts are acceptable. Other than thanI would build a support wall to place the trusses on and use I beams.
The floor is still going to be at 11 ft and give him a 5' head room up there. If it is only storage that might be OK, but for anything else the roof trusses need to be changed. That is something I would want and engineer to check out. The new floor might provide enough lateral support to allow a major change in the location of the tie rafter, but I would not do anything without a sign off from a sturctural guy.

[SteveS]

First off, I would like to thank all of you for some REALLY good replies to my email...they are educational and motivational!

Let me point out a few things that may help to bring some sanity to this project of mine:

I am not pre-determined to do anything in particular since my goals for a second floor are: LOTS of additional storage, less lower space to heat, better air filtration in a smaller space, easier to make cosmetic changes. (I am trying to make my shop LOOK nice....hardwood walls, etc.).

While the second floor does not have to be enough to stand tall, I'm over average height at 6'2") I do not want to crawl either. However, I would not be opposed to changing/modifying the trusses if I am able to gain more headroom in the end.

I also am certainly not opposed to adding another set of 2x4 or 2x6 uprights to the wall so that I can put the joists on 12" centers.

The roll-up door would be GLADLY changed to a sliding barn-door type. In fact, for appearance and heating reasons, I would LIKE to do this. The door also would not have to be so wide.

Let me also interject that my shop is actually about 40 feet in length and 26' wide. I intend to put a dividing wall near the center of the 40' to partition it into two halves. (not exactly halves, but for sake of simplicity, we'll say halves).

One last thing...I intend to use hardwood ceiling material for the "downstairs" ceilings eventually. So the extra weight issues of that should be calculated as well.

I will make a detail drawing with measurements later in the day. I will also check on the laminated I-beams to see what they will span and a cost for them.

Thanks again...rock on!

Stay tuned....

[Danford C Jennings]

Steve,

Would there be any advantage to using these instead of 2x6's or 2x8' other than getting away with larger centers? Yes, since a 2 x 6 or 2 x 8 won't span 26', they are more readily available, and easier to set.

I was not able to find if you told me what size joist I should use. How do they connect since I doubt I will find 26' lumber. They use plates like the truss structures? That's because I didn't recommend a joist size, just an example of what is required if 2 x 12s are used. Normally, wood "I" beams are used in Western framing where they are set on the walls' top plate 1 1/2" in from the outside edge to allow for the 2 x bond (header), they are set by 16ds nailed into the top plate, then the bond is face nailed to the ends of the "I" beam with 16ds. In this instance, I'd nail into the ribbon strip and toe nail into the studs and use cross bracing. Again, you need to check with your building department. Explain what you are wanting to do and they'll be able to reference to the UBC or whatever the code authority is....

When you say, "check with your buidling department" I am not sure what this means? The "building department" is the local goverening "authority" on structures, they issue permits, perform the inspections, and answer questions such as yours.

Dano

[SteveS]

OK...more info:

George Pacific's WI-80 16" I-Beam will simple-span 28'6" on 16" centers with an allowable .5" deflection.

At a cost of $62 each, I will have a little over $800 tied up in the I-beams.

If I were to reduce the width of my garage door and/or replace it with a sliding door instead of one that raises, I could place a cross beam at appx. 6'- 8' out from each wall. So the span would be reduced to 10' or 12' (I assume would be MUCH easier and less expensive).

How would this design look? How would the cross beams/joists/support (whatever they're called) be incorporated into the design? Danford?

Thanks a lot.

[SteveS]

Dano,

Thanks for the drawings, however, they are a tad small to make out the details. If you do not want to upload them, you can email them to me at:
steves@suscom.net

Thanks!