Author Topic: 20x42 dual lofts concept... need input please!  (Read 12696 times)

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Offline Don_P

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Re: 20x42 dual lofts concept... need input please!
« Reply #25 on: December 30, 2012, 06:04:44 PM »
I think I was still modifying while you were typing but were on the same page I think.
I'd platform frame it. This ridgeBOARD would be several pieces long but this is no problem, yes it is to code, remember the "trusses" have no ridge at all... we discussed that earlier this week, can't remember which thread that was at the moment  ??? A ridgeBEAM is another animal but I won't go there if we don't need to to avoid confusion.

Offline Steve_B

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Re: 20x42 dual lofts concept... need input please!
« Reply #26 on: December 31, 2012, 04:36:16 AM »
I think I was still modifying while you were typing but were on the same page I think.
I'd platform frame it. This ridgeBOARD would be several pieces long but this is no problem, yes it is to code, remember the "trusses" have no ridge at all... we discussed that earlier this week, can't remember which thread that was at the moment  ??? A ridgeBEAM is another animal but I won't go there if we don't need to to avoid confusion.


Don... going with a ridgeboard, could you just give me an example of what dimensional wood the board is made out of, and what dimensional wood the rafters would be made from?

Just trying to visualize sizes and depth
It's all about the kiddies I tell you...

Offline Don_P

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Re: 20x42 dual lofts concept... need input please!
« Reply #27 on: December 31, 2012, 05:55:32 AM »
If the rafters are a part of the insulated envelope then the insulation requirement controls their depth, in that case I typically frame with 2x12 rafters. There is a requirement that the ridgeboard be deep enough to provide a bearing surface to the entire plumb cut at the ridge. At a 12/12 pitch that requires about 16" of ridge depth. I'd use a 2x6 atop a 2x12 and extend the 2x6 out to support the fly rafter.

I have satisfied the structural neccessity with lesser depth members and furred down the sloped insulated area to satisfy those requirements as well.

I believe you are building in piedmont SC and am going to make some assumptions for this next part to show the other end of the spectrum. I'm going to assume 24" on center spacing, a 20 psf live load+10 psf dead load. I'm going to assume the 2nd floor walls are 8' tall and the ceiling joists rest on those walls and the ceiling is attached not to the rafters but to the ceiling joists, the insulation is on the ceiling. Now we are just looking at the structural requirements of the rafters. In that situation 2x6's would work for the rafters. The ceiling joists would need some thought. They are spanning 20' and if you keep the pitch high there is going to be storage up there, I'd use 2x12's. If the pitch drops to unuseable height in the attic that could go down to no less than 2x8's. Of course if there is an interior load bearing wall that can support the ceiling the cj's can be shallower. Don't build off of that, you need to confirm those assumptions, it is just to show the range and point out another potential offset in costs.

The R802.5.1 tables flesh all that out further, read the headings and footnotes carefully and make sure you are on the right on center spacings. Ignore the southern pine spans and use the SPF spans for southern pine till they correct the tables (we grew em too fast and they just got busted down)

A little more terminology, when the word "dimensional" is used it is generally referring to 2x lumber of some sort (actually 2x-4x) as opposed to 1x boards or >5x timbers. Every profession has its lingo that can be confusing. You used the term correctly  :).

Offline John Raabe

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Re: 20x42 dual lofts concept... need input please!
« Reply #28 on: December 31, 2012, 09:54:25 AM »
Just want to give a New Year shout-out to Don_P and all the help he gives folks on this forum!

Don, your experience, patience and thoroughness has been invaluable to so many of the owner-builder projects people post here.

THANKS FROM ALL OUR 7,391 COUNTRYPLANS MEMBERS!
None of us are as smart as all of us.

Offline Steve_B

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Re: 20x42 dual lofts concept... need input please!
« Reply #29 on: December 31, 2012, 11:14:38 AM »

Indeed John... Thank you to all who have furthered all of us in gaining more knowledge and coming closer to the dream of building your own house! There is invaluable information here in the forum from many people who are willing to help us beginners


Don... Here is an idea taking in account all I have read in this post... here is the scenario

I am going to buy the plans for the 20 x 34 universal 2 story house. I am going to build that same sized house on a concrete slab and lay out the first floor and stairs exactly how they are in the plan. I am going to platform frame the second floor just as in the plan.  ~( now for the changes )~  I may lower the 2nd floor wall height to 5' or possibly keep it at 7' 6" and build the roof as a ridgeboard roof with no 2nd floor ceiling at all or joists. The entire 2nd floor would have the roof visible as there is no ceiling or "attic floor" installed. I am going to adjust the second floor floorplan to have 3 bedrooms only with a some storage space. The insulation would be installed inside the rafters which would be 2x12

Will this scenario work as I wrote it? Would I need rafter ties?

It's all about the kiddies I tell you...

Offline Don_P

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Re: 20x42 dual lofts concept... need input please!
« Reply #30 on: December 31, 2012, 03:36:18 PM »
John, Thank You, I appreciate that. I do agree with Steve, there are many good voices here, we sharpen one another  :).

Steve, yes you would need either rafter ties in the lower third of roof height or a ridgeBEAM to do that. The beam would likely need at least a couple of posts from ridge to footings for the full cathedral. I'd lean towards a scissor truss roof to keep the floorplans open.

Offline rwanders

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Re: 20x42 dual lofts concept... need input please!
« Reply #31 on: January 05, 2013, 09:03:24 PM »
http://countryplans.com/smf/index.php?topic=5513.msg70414#msg70414

Steve B;

Found a bunch of posts related to the cabin I built in Alaska 2008-09 timeframe. It has a few interior pictures of cabin at various stages.  Don't let design problems discourage you excessively. Most can be resolved at design stage and if that stage is done well problems that arise during construction can be overcome without great trouble. When you see homes/cabins being framed ask the builders if they would let you take a look at their work---it's a good way for a person with limited experience to gain some  good mental pictures of framing details [just be sure and look at good workmanship examples]. You can do it. You will make some errors; probably take what seems to be a long time; wish you had done some things differently [without a doubt]; but the satisfaction you will gain building your 'dream cabin' [even if limited by $$$] will be priceless.

I think the link above will get you to my 'dream cabin'. If not search for rwanders in owner/builder section.  It would not be everyone's 'dream', but it was mine. It was a great adventure and done with the input of many members of this wonderful forum.  I have a lot of other pictures of completed cabin interior---can email to you if you want to reveal address to me [via personal note?]
Rwanders lived in Southcentral Alaska since 1967
Now lives in St Augustine, Florida

 

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