Replies

1. 
   Guest_ | May 17, 2000 10:07pm | #1

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   I might be wrong, but this seems goofy. You want to cantilever so that you don't have to use long posts, is that guess right? Also, I assume you are cantilevering the 4 foot dimension, not the 12.

   I don't know the true definition of cantilevering, but unless I'm missing something, this is not it. What will carry the 2x10's? That's the important thing. Who cares about the connection to the I joists, just sister the treated lumber up tight next to the I joists and nail them off.

   But if you think connecting the lumber to the I joists and "cantilevering" this connection on top of a plate will be good enough, don't invite me to any of your parties. And if you are thinking about through bolting the lumber to the I joists, you should talk to an engineer or someone at the I joist manufacturer about this.

   Me, I'd put down posts.

   Good luck.

1. 
   Guest_ | May 19, 2000 05:04pm | #2

   *The definition of cantilever in Webster's isn't that precise. I've heard people talk of "true cantilever's" as objects that project horizontally their whole length, attached and supported at one end only. This would be like a basketball rim.The situation here seems to be treated joist running from the end of the balcony to a point well inside the structure. For joists to cantilever 4' they must run back into the structure at least 8'. Anyway the structure obviously should have professional design/engineering for this feature.If your flahing details are inadequate the consequent water damage to the I joists will be disastrous.I cantileverd a 4 x 8 balcony on my cabin by running 20' joists in a 16' wide structure. joe d

1. 
   Guest_ | May 20, 2000 08:15pm | #3

   *One more vote for stopping right now and getting a pro to design it. There are stress factors from the cantilever, material choice, wind loading(depending on just what beach), etc. These will affect not just the balcony but the entire structure.Not to be unkind, but the mere fact you had to ask says you don't know enough. So, spend a few bucks and get a good design. It will help give you more than one good night's sleep.

2. 
   Inc._Jeff_Stanley-Prestige_Homes | May 21, 2000 12:47am | #4

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   The idea of "sistering" dimensional lumber along side of engineered lumber sounds like trouble from the get go.

   If you use dimensional lumber wide enough to catch both the top and bottom chord of the I-joists you definately will have some major flashing issues at the point of exterior portrusion. Not only that, "through bolting" only increases the risk of the holes enlongating over the course of time and use.Resulting in subsequent "humps" in the floor inside.

   You did'nt specify what depth joists you were using so, I'll use 9 1/4" as an example.

   As most of us professionals know, the basic rule of cantilevers is that you must be at least twice as far in the building as you are out of the building....at a minimum. So with that in mind, the framing should be much like it is when you are framing out a fireplace hearth. At the ends of the 12' deck you need to run paralams from the back of the house in to the steel beam (or whatever else you are using as your center load bearing point.)From there , put in a paralam perpindicular at least 8' back from the outside of the building.All your I-joists in front of the header you would terminate with typical hangers and the joists in the back you would use dimensional 2 x 10 terminating at the outside of the plate with their appropriate hangers.

   "Sistering" now becomes easy because you are nailng or bolting dimensional lumber to dimensional lumber.

   Also, since you are only cantilevering 4' I would use 2x8 PT lumber. Holding the 2x8 all the way down to the bottom of the 2x10 on the outside wall and up off the bottom of the 2x10 approx. 1" in at 8' you will create enough pitch for water to run off and also since you have gone from 2x10 to 2x8 you have eased the flasing situation.

   Of course thats just my opinion, Good luck!

3. 
   Guest_ | May 21, 2000 03:08pm | #5

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   Jeff,

   I had to read your post about 3 times before I think I figured out your system. But I think it's asking for trouble because:

   1. 2 x 8's are a bit wimpy here, and if the joists are say 9 1/4", stay with it.

   2. I think you will have leverage upwards at the header because the plate will act as a fulcrum when a load is placed on the balcony. Will normal joist hangers handle that? I seem to remember they had a hole on top of them

   3. Why terminate the regular joists within the header system at the plate at all, and sister more joists? Why not just run the whole joist right out to the end of the balcony?

   4. I don't think running the cantilivered joists on an angle is good at all. Other ways to handle drainage.

   5. What about the inside floor at the header? Do you think this is good enough support for the inside of the house? I see a flimy 12 foot section, a weak link.

   My original point about sistering dimensional lumber along side of engineered lumber was the same as yours. I didn't think is was a good idea either. My point was that he needed more support from within.

   Perhaps your system would work out, I'm no engineer, but I think one should be consulted.

4. 
   Inc._Jeff_Stanley-Prestige_Homes | May 22, 2000 02:09am | #6

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   Mad Dog,

   I am sorry if there was some confusion on my system but, hopefully you got it.

   In response to your claims:

   1- Pt 2x8's are rarely weak when spanned a measely 4'.Plus using a smaller joist lowers the deck from the sub-floor tremendously reducing flashing problems.
   2- You mention the plate as a fulcrum?.....unless he is putting a Jacuzzi on this balcony, I seriously do not think this is an issue.
   3- You mention running the joists all the way out? Around here in Chicago, we MUST use Pressure treated lumber outside. Thats just common sense.
   4- Angling the joists with minimal pitch is a common practice around here....whats wrong with it?
   5- Obviously, the paralams on either end should be sized accordingly to eliminate any weak links. TJI has these tables in their spec book. Its just a few simple calculations away.

   We run into all kinds of thses crazy framing issues seemingly every day.
   I don't know....everybody has different ways of doing things. But I do know this, as a builder of MILLION dollar custom homes, we have an excellent reputation. We must be doing something right!

5. 
   Guest_ | May 22, 2000 07:30pm | #7

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   I was just going through my mail and found a new copy of the APA/Engineered Wood Association's Design/Construction Guide, I-Joists for Residential Floors. On page 17, there's a detail drawing of how to sister solid lumber joists to I-joists for the purpose of a cantilever balcony, exactly this scenario. It's a dirt-simple nailed connection. Contact the APA for a copy at (253) 620-7400. It may be on their website, as well, I haven't checked. http://www.apawood.org.

   If all of that fails, e-mail me your fax #, and I'll get a copy to you.

   Andy Engel

1. 
   Guest_ | May 24, 2000 04:56am | #8

   *Hi Jeff,It's all communication, I think. As far as point 1 goes, I personally feel like 2x8's are a big compromise over 2x10's for this, just for a flashing advantage. Remember, he'll have to have a guardrail system and still build it for a live load too. But, if 2x8's are the way, then maybe space them on 12" centers.2-probably so. I was thinking about the way forces act on the cantilever but this is a minor point and I think you have it right.3-I most definitely meant PT joists. I thought, why bother with I joists within the header system, why not use PT and just run them out?4-Probably no big deal for an unenclosed balcony, but what's the advantage if deck boards are used, why have the tilt? I didn't reread the thread, and don't remember if the finished floor surface of the balcony was addressed. If it were solid, then I'm with you, otherwise I'll be a jerk and say that the 2x8's might wilt into a slight slant anyway, and you'll get your pitch like that!5-good answer.I've never built a million dollar HOUSE, and may be guilty of overframing, but stuff like this sort of requires it, in my opinion.

1. 
   Guest_ | May 24, 2000 07:51am | #9

   *I've been getting quite a few projects finishing the daylight basements of recently built homes in my area. This has given me a chance to view the exposed framing and I've noticed that the builders have done exactly what you are describing for your balcony project, sistering standard 2x10s with the I-joists of the main floor and cantilevering them outside 4' to create a small deck. (Unfortunately, they used standard fir which no doubt will need replacing in a few years) They merely nailed them off to the top and bottom of each chord. In the first home I did, though, I saw firsthand the result of the builder neglecting to flash or seal the joists which penetrated the exterior wall - we had a bad storm one day with horizontal blowing rain. Rainwater followed the joists right in through the unsealed cracks and puddled on the floor, soaking the framing and insulation on the way down. I'm thankful I hadn't sheetrocked that room yet before discovering this flaw and was able to properly seal the joists before finishing the room.One other observation to share - I saw another house where the owner had placed a hot tub on a cantilevered deck. Over time the weight had bowed out the exterior wall and created a "hump" in the floor adjacent to the deck. Although I consider myself somewhat of a novice contractor it seemed to me that a couple posts and beam would have been cheap insurance against this major structural damage.

1. 
   Guest_ | Jun 06, 2000 08:37am | #11

   *If your going to be using an engineered floor: every engineered joist floor I've rolled has come with drawings from the supplier that quite often supercede the original structurals drawn for the house. They do their own calcs to limit liability. It would seem to me that the discussion is moot. Let the supplier see the plan (architectural) and have him supply the structural floor details, which are usually just plug- ins from his standard details. Definitely a no brainer in this case for the I-joist engineer. You do have architectural drawings, don't you Mr Jurcik?

6. 
   M._Jircik | Jun 06, 2000 08:37am | #10

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   We are going to build a beach house with a small balcony(4'12') on the second floor. I plan on using I Joists for the floor & PT 2x10 for the exterior deck framing. I am going to cantcantilever deck but my question is how do I make the connection between the I joists & the dimensional lumber? Is there a hanger on the market that I don't know about?