Author Topic: floor joist-beam connection  (Read 3222 times)

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Offline Joel in Alaska

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floor joist-beam connection
« on: January 27, 2009, 11:07:06 PM »
Greetings from Alaska!  First time poster here.  I stumbled upon your website a few months ago - what an information treasure!  I am currently in the planning phase for a 20x28 1.5 story recreational cabin near Anchor Point Alaska.  I was thinking of building the structure on top of three parrallel beams supported by three rows of 10" (dia) sonotubes.  I gather from some of the projects profiled here on this site, that some folks cantilever floor joist slightly over the outside beams so that the piers remain tucked neatly under the building.  This sounds apealling to me as it would allow me to frame and insulate skirting around the building without interfernce from the posts.  I have a couple of questions/ concerns with this appoach.  First off, is anchoring the structure to the foundation.  If the rim joist and bearing walls are offset from the beams below (I am thinking appox 6-10" cantilever), how are people anchoring the structure to the beams against seismic uplift?  Would you use rafter type clips the floor joists run over the beams?  I was also wondering if there might be concerns with attaching an external deck to a rim joist that was not directly bearing on a beam below-are their sheer forces working to seperate the rim joist from the floor joists?

I would be greatful for any advice or thoughts you might have on this.

Cheers

Joel

Offline n74tg

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Re: floor joist-beam connection
« Reply #1 on: January 28, 2009, 04:56:53 AM »
First off, welcome to the forum.

Seems that several places I read that you can cantilever the floor joists out the thickness of the floor joists with no problem.  So, for 2x10 floor joists, 9.25" would be okay.  Now, if you plan to attach a deck to the rimjoist that is on already cantilevered out floor joists, it would depend on how you had the deck supported.  Personally, I think that you would need a support beam under the deck pretty near the rimjoist, with the other support beam being on the opposite side of the deck.  In other words, the rimjoist does not support the deck.

I'll be interested to see what others say. 

Keep us informed on what you decide to do...then take pics once you build it.
My house building blog:

http://n74tg.blogspot.com/

Offline glenn kangiser

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Re: floor joist-beam connection
« Reply #2 on: January 28, 2009, 05:02:18 AM »
w* Joel.  I have to get to work but I'm sure others will soon get you some info.  On the blue bar above is a search button.  You could search porch deck attach possibly for some info.  There are 3 searches above - not all work the same.
"Always work from the general to the specific." J. Raabe

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Offline rwanders

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Re: floor joist-beam connection
« Reply #3 on: January 28, 2009, 06:33:36 PM »
Were you planning for the deck to be parallel to the beams or perpendicular to them?  If perpendicular, then the rim joist (which I would double if using 2x lumber) would be supported by all three beams and should be sufficient. It is always preferable to use throughbolts to attach your ledger instead of lagbolts---always easier to do in new construction when you are framing your platform. If parallel, you could always not cantilever that beam for added strength and it would not be visible in that case too. 

There are many here with more experience than I who will probably chime in also.

Welcome to the forum

I am nearing completion of my 1 1/2 story near Willow

 
Rwanders lived in Southcentral Alaska since 1967
Now lives in St Augustine, Florida

Offline Joel in Alaska

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Re: floor joist-beam connection
« Reply #4 on: January 28, 2009, 09:53:33 PM »
Hello Rwanders

I am anchored down in Anchorage too. Small world!  with respect to the deck orientation: I envision the deck wrapping around two sides of the cabin- in the front (gable wall) the doubled up rim joist(s) would indeed rest on the but-ends of three floor beams and I dont see an issue with attaching a ledger board here for a deck- but wrapping around to the side (bearing wall) the double rim joist would be counterlevered out slightly from a bearing beam and I was just wondering if there might be any issues attaching a ledger board and joist hangers to this unsupported rim joist.  Thinking about this further, I think what might work would be to set up  a series of support beams for the exterior deck on this side of the building  at a right angle to the wall (ie same orientation as the deck beams out in front of the building) and run all the decking joists on both sides of the building across this parallel series of beams. (explaination clear as mud right?).

My bigger concern however it trying figure out the best way to tie the structure down to the foundation beams to resist wind/seismic uplift - if the rim joist was flush with the outside beam you could extend and nail sheathing over the support beams or use strap ties, but when the beam is actually tucked back from the edge of the wall I imaginge you would have to figure out some way to connect the floor joists where they pass over the beam.  I have searched for examples/explainations of how others have done this here, and on other sites and am still scatching my head.  I understand how this is done using hurricane clips for deck construction - but have not seen this application for a house/cabin with post and beam foundation.  looking for any thoughts or suggestions on this from forum members.  Our lot is not in a high wind zone, but as you know (eg just last week) seismic jolts are a reasonable expectation. - just want to make sure I have a good solid connection with the foundation.  As for that big puffing volcano across the inlet- not sure what you can do about that but pray!

Offline harry51

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Re: floor joist-beam connection
« Reply #5 on: January 28, 2009, 10:35:01 PM »
These  http://www.strongtie.com/products/CFS/S_H-H.asp  are designed for seismic as well as hurricane reinforcement of joists to beam connections, etc. I'd suggest picking up a Simpson Strong-Tie catalog at the lumber yard. They usually have them to give away and they have a lot of useful info in them.


I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them.
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Offline wildcottonroad

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Re: floor joist-beam connection
« Reply #6 on: January 30, 2009, 07:29:29 AM »
Joel,

I'm also putting in a place near Anchor Point.  The property is just off Tall Trees and back a few miles.  Where are you putting up your place?

Jay

Offline kenhill

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Re: floor joist-beam connection
« Reply #7 on: January 30, 2009, 08:57:28 AM »
Another Alaskan here.  Live in Anchorage, building on Red Shirt Lake near Willow. 

Offline Don_P

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Re: floor joist-beam connection
« Reply #8 on: January 30, 2009, 01:59:25 PM »
The best way to build a deck is to make it self supporting on its own "legs" and then attach it to the house just to keep the house from wandering off.

There's a good deck building guide available as a free download here;
http://www.awc.org/Publications/DCA/DCA6/DCA6.pdf

Offline Joel in Alaska

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Re: floor joist-beam connection
« Reply #9 on: January 30, 2009, 06:53:29 PM »
Hey!  Nice to see some Alaskans reach out.  Wildcottenroad we puchased a lot off of Danver which is down by the mouth of the River.  good road access and about 1/2 mile walk to the beach. I Love the area and am stoked about the project.