Author Topic: 20x30 1.5 story: Ceiling joist alternatives  (Read 7849 times)

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Offline sharbin

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20x30 1.5 story: Ceiling joist alternatives
« on: September 10, 2008, 09:43:54 AM »
Good day all,

 I finished (well almost  ::)) putting up the walls and now is the ceiling joist turn.
I was looking around for 2x12 20' (for loft) and 2x8 20' (for open space) but I am having a hard time finding such length.
I called one of the lumber yards and they suggested an LVL. So my question is would that be a good alternative? Of what dimension should it be for the loft and for the open space (cathedral)? is it too heavy for 2 persons (me and my wife) to lift and move around ourselves? Can it be bevel cut (where the rafter joins the joist)?

Are there any other lumber alternative, keeping in mind that for the cathedral ceiling I would like to have a heavy lumber look.

I thought that my last resort is to use posts and 10 feet long beams across the 30' with 15' ceiling joists on one side(living room area) and 5' on the other side (kitchen area) all doubled up evrery 4 feet.

Thanks a lot

Sharbin

Offline peteh2833

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #1 on: September 10, 2008, 09:47:37 AM »
I decided to use a center beam down the center to split the 20' into 10'. I'm using 4x8x10's rough cut and  2 center beams that are 6x12x15 rough cut supported by 3 6x6x8 rough cut posts. Don't know if that helps you out at all. Pete
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Offline John Raabe

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #2 on: September 10, 2008, 06:06:03 PM »
I assume you want to do the beam and decking ceiling/floor (using 2x6 T&G) shown in the Loft Framing plan (sht. 5) and Loft Floor Details (sht. 7). You could substitute a couple of LVL beams for the double 2x12's called out. My charts show that a double 1.8E G-P Lam LVL 1-3/4" wide x 11-1/4" deep @ 48" o/c would give you better than 1/360 deflection. This would be virtually the same size as the double 2x12's.

If you want to have the open cathedral ceiling shown in the optional Cathedral Ceiling Detail shown on page 9-20a in the booklet, you could use a single 9-1/4" LVL @ 48" o/c if you can't get the long 2x6's for the rafter tie shown. Note, however that this can be built-up from stock less than 20' long as long as joints are staggered at least 48" and you use glue and nails as you would in a built-up girder. This rafter tie only works in tension, not as a load carrying beam.

Pete's option is a sturdy alternative with (probably) a better finished look than the double LVL's.
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Offline sharbin

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #3 on: September 10, 2008, 07:20:33 PM »
Thanks Pete and John for your reply. I know that Pete's way would be a good alternative, but I wanted really to have Cathedral ceiling plus I am in a time squeeze before the cold/snowy weather kicks in, so I thought with using LVLs it will go much faster.

Ok that gives me a good alternative, albeit an expensive one ??? (it costs $8 CAD per foot).
What about beveling cut the LVL, is there any issues or difficulties in cutting it?
One last thing John, you mentioned below 2x6 rafter ties which I think you meant 2x8, am I right?


Offline John Raabe

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #4 on: September 11, 2008, 08:45:50 AM »
Yes, 2x8's... 2x6 would be fine too but 2x8 has a better scale.

Yes. you can knock off the bevel cut corner as long as you have full width bearing on the stud walls.
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Offline sharbin

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #5 on: September 15, 2008, 09:25:32 AM »
Hello Pete,

 In case you did not recieve my email, could you provide some pictures to get an idea on how it will look like with post and beam?

Thanks


I decided to use a center beam down the center to split the 20' into 10'. I'm using 4x8x10's rough cut and  2 center beams that are 6x12x15 rough cut supported by 3 6x6x8 rough cut posts. Don't know if that helps you out at all. Pete

Offline John Raabe

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #6 on: September 16, 2008, 11:28:53 AM »
Here is a loft over a bedroom built with 2x6 t&g car decking resting on 4x4 beams that bear on hangers supported by 6x8 beams.

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Offline Redoverfarm

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #7 on: September 16, 2008, 01:18:45 PM »
John how much distance are we talking about on the span of the 6X8's?

Offline John Raabe

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #8 on: September 16, 2008, 03:32:40 PM »
The 6x8's span 12' and there is 5'-6" between them. The 4x4's are 32" o/c. So that is basically a 12'x11' floor.
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Offline Redoverfarm

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #9 on: September 16, 2008, 04:14:31 PM »
John the reason I asked is that 4"x4" is a poor lateral support member IMO.  Do pretty good in the verticle department but they usually have too much deflection horizontal especially on longer runs.  I am sure that in the short run it is working out OK.  Wonder if they considered 4"x 8"?

Offline sharbin

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #10 on: September 16, 2008, 06:30:40 PM »
Thanks John for the photo.
I think I will go with post, beam, and decking for the loft area. However, it is the cathedral ceiling area part that I am not sure how it would look like.

Here is a loft over a bedroom built with 2x6 t&g car decking resting on 4x4 beams that bear on hangers supported by 6x8 beams.



Offline peteh2833

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #11 on: September 29, 2008, 03:20:24 AM »
Sharibin, Sorry for the delay in posting. I forgot to check in lately. I will post some pics as soon as I get the beam and posts installed. Should be this weekend. I'll let you know. Hopefully next weekend I'll be throwing up some rafters. Pete
Here is a link to my thread    http://countryplans.com/smf/index.php?topic=3252.0
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Offline sharbin

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Re: 20x30 1.5 story: Ceiling joist alternatives
« Reply #12 on: September 30, 2008, 07:13:13 AM »
Thanks Pete.

 

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