BCI's for 2nd Floor

[akriverunner]

I am trying to build my second floor without putting a center beam under it. I would need 14" 6000 series BCI's but I can only get them in a 24' length, I'm spanning 20' so I would be wasting a total of 100'. On top of this issue they are about $100 each. I'm wondering if I can use 11&7/8 with web stiffeners instead?


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[andweav]

I'd be more likely to go with the 24' 14s and splice the four foot cutoffs together with 3/4 ply and have 8' joists for a shed floor or whatever.

The 12s feel spongy at 20 feet and most people hate that in a floor. If it's just a bedroom maybe ok.
If you pick up any of the center load w interior walls that helps.

I've never been on a 20" span of the 11 7/8 with a spacing of 12" oc. Might be ok. might be more expensive than if you just use the 14s

Obviously you can do it and the floor won't fall under it's on load. Just more deflection. How much weight up there? How much walking?

 

[akriverunner]

There will be three bedrooms up stairs, pretty much only used for sleeping


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[otternorth]

You must have looked at the span tables http://tricontruss.ca/resources/instructions/boisecascade_bci.pdf <-there..You have some options going to 12"oc and applying a ceiling that drops you into the 5000 series.
Have you considered an upset, mid-span beam of laminated versalams? You need to use hangers and need beam pockets at each end.


Like one poster said....with the cut offs you could have a stout shop floor.

 

[akriverunner]

I may go the 11&7/8 x16" oc 6000 series route. I will be doing Sheetrock or wood ceiling underneath. I can always use 3/4" ply to stiffen the webs if it's too bouncy.


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[iofthetaiga]

I am trying to build my second floor without putting a center beam under it. I would need 14" 6000 series BCI's but I can only get them in a 24' length, I'm spanning 20' so I would be wasting a total of 100'. On top of this issue they are about $100 each. I'm wondering if I can use 11&7/8 with web stiffeners instead?

Why do you believe you can only get them in a 24' length? SBS sells them at any length you want; they require you order them to the next longest foot (need 20 footers, order them at 21). As far as options go, BCI publishes a span table paper (available free at SBS) which makes it easy to compare options. Off the top of my head, I believe you can span 20' with less than a 14" web, depending on your OC spacing. Another variable to consider is that a shorter web product may not be less expensive depending on which are regular stock pruducts vs which are special order. I recently purchased a bunch of them for a project; could have made do with 11 7/8" webs, but 14" were less expensive because they're regular stock items, whereas the 11 7/8" are special order items...

 

[akriverunner]

I talked to sbs today. Wasilla store only stocks 9&1/2 and 11&7/8 6000 series. My price there for the 11&7/8 20' long is $39.10. ANC store has 14" 6000 series but they start out at 24' and go up in 2' increments he said and they are $100 for a 24'er. The price difference is $60 per joist which equals $1500 for my floor.


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[iofthetaiga]

I talked to sbs today. Wasilla store only stocks 9&1/2 and 11&7/8 6000 series. My price there for the 11&7/8 20' long is $39.10. ANC store has 14" 6000 series but they start out at 24' and go up in 2' increments he said and they are $100 for a 24'er. The price difference is $60 per joist which equals $1500 for my floor.

Never would have guessed that different SBS stores would inventory different products as their standard stock... Anyway, am quite sure you can span 20' with less than the 6000 series 14"web. Whether you'll be happy with the stiffness, only you can answer.

 

[akriverunner]

Yeah. I guess wasilla doesn't stock as much as anc. I will try the palmer store. I will probably just go with a center beam, it will be stiffer and cheaper.


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[iofthetaiga]

Yeah. I guess wasilla doesn't stock as much as anc. I will try the palmer store. I will probably just go with a center beam, it will be stiffer and cheaper.

If you go with a center beam and only span 10', you could then use dimensional lumber and likely spend a lot less...

 

[akriverunner]

Yeah for sure


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[AKDoug]

I've done 11 7/8 on 16oc at 20' and it will make a code floor, but it's bouncy. If it was a cabin, I'd live with it.

 

[akriverunner]

Thanks AKDoug. I'm going to try it and if it's too bouncy I will fill the webs with 3/4" plywood


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[cdubbin]

Thanks AKDoug. I'm going to try it and if it's too bouncy I will fill the webs with 3/4" plywood


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That's a pretty grueling amount of work....I would just sister an extra joist in every four feet and call it good. If the floor is still too bouncy for your taste, you can sheet the underside of the bci's with 3/4" ply, glued and nailed. It will stiffen the floor a lot.

 

[akriverunner]

I was planning on some sort of ply on the underside anyway, something with a natural wood look.


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[outdoor1]

YOU COULD bury the beam and hanger the joist then you could use the shorter joist.

 

[limon32]

If you build it bouncy I'm assuming you'll be carpeting? Tile would be out of the question and hardwood will be noisy.


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[EBalaska]

When I build cabins I always get the +2' for joists so that way I can add blocking to the joists to help reduce bounce. I would look at all the options out there. Costs being the major one. There are several ways to look at it. 1-Center LVL beam with dimensional lumber, 2- BCI that freespan and use the extra couple feet for blocking, 3- smaller BCI and fill the webbing with plywood, 4- see if the cost of ordering 40' is the same and then have SBS cut them in half.

 

[Paul H]

Thanks AKDoug. I'm going to try it and if it's too bouncy I will fill the webs with 3/4" plywood


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3/4" ply isn't exactly free, if you look at the cost of the all plywood you'd need, you'll likely be near the cost of the 14" BCI's with a whole lot more labor.

Stiffness in a beam is gained primarily by depth, not width with some gain by going to closer centers to spread the load but at an added cost. I'd seriously consider the 14" BCI's as you're supporting the weight of interior walls, furniture and people.

As a friend is fond of saying, it takes just as much labor to do a job with the right materials as it does to do a job with marginal materials, might as well do it right the first time and not have a bunch more labor and materials to try and come up with a fix later. This is one of those decisions where you're pretty much stuck with the results of your choice with no easy way to fix it if you're unhappy down the road.

 

[iofthetaiga]

3/4" ply isn't exactly free, if you look at the cost of the all plywood you'd need, you'll likely be near the cost of the 14" BCI's with a whole lot more labor.

No kidding! What an expensive PITA that would be!

To date, I have built two structures using 14" BCI's. In both cases the free span was 24'. The first used series 90's 16" OC, decked with 1.125" tongue and groove subfloor plywood glued and screwed, and 5/8 type-X sheetrock hung on the underside. The second used series 60's 24" OC, decked with 3/4" ACX plywood glued and nailed with ringshanks, and 1/2 inch plywood hung on the underneath side. Both made acceptably stiff floors, well above minimum code requirement.