Author Topic: 20x38 1 1/2 story Comanche Texas  (Read 12402 times)

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Offline Zavoot

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20x38 1 1/2 story Comanche Texas
« on: April 27, 2009, 09:33:56 AM »
Hey - just getting started here and wanted to post updates and pics so I could get feedback

First - the site is on a corps of engineers lake and they are pretty specific about elevation. The dam is 1197 - and the flood level is 1200 - and they want 3' higher than the flood level. My land is about 1197 to 1200 so I had to raise everything and my final floor height is 1203 2 3/4".

Went with 18" diameter holes appx. 2' deep - Rented a skid steer to make it easy - I had 14 of these and there were tough thatches of roots to get through. The bottoms of the holes were nice solid calechi rock.
Looks like a moonscape!


I laid out the posts in a 20x37 1/2 pattern - but I set the 6x6 post receivers in the concrete in the middle of the pattern - meaning the posts were about 3" outside the center line on all sides - resulting in a outside dimension of 20 1/2' x 38'.
(Foundation 6x6's set)


Since I'm using floor trusses there is no problem on the first floor. I wanted to use 2x12 for the loft but finding 22' might be a problem.
(floor trusses ready to go)



(Cantilever of floor trusses)



OK - so these are 'trimable' trusses - however I would like to use the full 22' width -
Does anyone see a problem?[/size][/size]

« Last Edit: April 28, 2009, 04:41:31 AM by Zavoot »
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Offline Zavoot

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #1 on: April 27, 2009, 10:52:29 AM »
Got all the floor sheathing down for the first floor. I went with 3/4" T&G OSB - because I'm using 3/4 hardwood flooring which will add stability and it was $4 a sheet cheaper than plywood 8)


Used subflooring adhesive and a nail gun. McCoy's sent a truck with a fork lift and set the subflooring on the deck saving me a LOT of extra work - since I am doing most of this by myself.

Since my dimensions had changed I went to work with some 2x4's to 'lay out' a floor plan until I got it approved (wife and son) - then used spray paint to mark the floor for future reference.
NOTE: This is so much more effective than drawing on paper - sometimes it's hard to get a good feel for dimensions - hallways - etc.

« Last Edit: April 28, 2009, 04:44:29 AM by Zavoot »
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Offline MountainDon

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #2 on: April 27, 2009, 03:58:53 PM »
Looking good so far.

Before you progress past this stage though you should get all your post/beam, post/joist bi-directional bracing in place and well secured. Do not leave it till later. Do every post.

Right now just sitting there it likely seems quite sturdy. Brace it before the walls go up; the walls act like big sails in the wind.
Just because something has been done and has not failed, doesn’t mean it is good design.

If you didn't have the time or money to do it right in the first place, when will you get the time and money to fix it?

Offline Zavoot

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #3 on: April 27, 2009, 04:06:18 PM »
Got it! Thanks!
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Offline Zavoot

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #4 on: April 28, 2009, 07:08:36 PM »
Worked on bracing today - also did a lot of clean up because we had a lot of wind and about 1" of rain - Hey! I know how to make it rain in Texas - just put OSB subflooring down. Anyway took a little precaution and put down some 4 mil clear plastic - at least until the threat of rain ends.
I braced the ends of the trusses for some stability but more for a place to screw/nail my OSB sheathing from the walls.


Also had to take time out to get the 4x6's for the diagonals - with 14 posts I needed 28 3' pieces (LOT of work - even with 12" chop saw still had to flip them for every cut!)

So here are the diagonals in place - one corner and one center (am using 3 20d nails in top and bottom)


Comments?
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Offline MountainDon

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #5 on: April 28, 2009, 08:11:12 PM »
Bolts in holes drilled through would be best. Lag screws next down the list. However, I'm not certain of how critical those would be. I'm certain some of our experienced builders who get paid for what they do will have a definitive answer.

In any event any of the fasteners you use must be approved for PT wood. That means hot dipped or stainless for nails, lag screws or bolts; unless the bolts are 1/2" or larger in diameter, I believe. Have to check on that.

(If you lag screw anything in wood, drill the proper size pilot hole full depth for the lag length. Do not use a hammer to start them and crank it into undrilled wood. The wood doesn't like that and it's easier to twist off a lag screw like that.)
Just because something has been done and has not failed, doesn’t mean it is good design.

If you didn't have the time or money to do it right in the first place, when will you get the time and money to fix it?

Offline Don_P

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #6 on: April 29, 2009, 03:31:16 AM »
I think MD has covered it well  :)
It does even make a pretty large difference if you let the drill actually drill the hole Vs jamming it in to make the hole. This is the AWC connections calc, the same folks who made the joist and rafter calc. This is a real long URL I set it up for the post/brace bottom connection. You can play around with different combinations.
http://www.awc.org/calculators/connections/ccstyle.asp?design_method=ASD&connection_type=Lateral+loading&fastener_types=Lag+Screw&loading_scenario=Single+Shear&mm_type=Southern+Pine&mm_thickness=5.5&mm_thickness_text=&theta_angle_mm=45&sm_type=Southern+Pine&sm_thickness=-1&sm_thickness_text=5.5&theta_angle_sm=45&wash_thickness=0.125&fast_dia=0.5&ls_length=8&load_duration=1.6&wet_svc_factor=0.7&end_grain=1.0&temperature=1.0&submit2_LLSS=Calculate+Connection+Capacity

I don't mind nails if they are long enough and large enough, deformed shanks are much better than smooth (rings or spirals). Wood is a unique material compared to say steel, many small connectors is often better than one or two large ones as it has a hard time handling huge loads on small areas. It does take many small fasteners to equal one large one though. 1" is the absolute maximum you should ever see in a very large beam. In braces I like to "table" them in if possible, cutting a slight shelf to rest the wood on making a wood bearing on wood joint that is held tight by the connector. That is probably going to more than could be done in a timely manner here though. I like the lag idea.

For the overhanging joist, you can generally overhang up to the depth of a joist with no problems BUT with engineered products it always requires a check call to their tech number to get approval for anything outside of spec.

In the spectacular failures you usually see on the news its almost always connection failures, pull the trigger plenty and then pull it again  :)

Offline MountainDon

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #7 on: April 29, 2009, 06:50:04 AM »
Nice calculator. It does require a little study up on the terms used, but there is a brief help associated with it.


That's an excellent point on the deformed nails. I used mostly spiral and ring shank nails in the construction of our cabin. It's second nature for me; I totally forgot about them. They excel in pull out resistance.
Just because something has been done and has not failed, doesn’t mean it is good design.

If you didn't have the time or money to do it right in the first place, when will you get the time and money to fix it?

Offline Don_P

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #8 on: April 29, 2009, 05:53:20 PM »
Here's an interesting factoid;
A smooth nail assembled into wood that is above 19% moisture that then dries to below 19% loses 75% of its withdrawal strength, a hardened threaded nail (ardox) loses none.

Any deformed shank is worlds better than a smooth one under any conditions :).

Offline MountainDon

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #9 on: April 29, 2009, 06:02:56 PM »
Here at home we have a couple of shade roofs that I built 15 and 20 years ago. The roofs are framed more or less conventionally, but instead of solid roof sheathing I used horizontal 1x4's with what dried down to a 3/8' spacing. They provide shade and allow the air to move through; vastly superior to any solid roof over a patio or gazebo here in the desert where it does not rain much at all.

Anyways, when I built the first one I used mostly smooth shank box nails. Big mistake. Those nails would walk their way out of the wood after a couple seasons. I did some of the roof in hot dipped galvanized; they stayed in place much better. I extracted all the migrating box nails and replaced them with galvanized ring shank. Never had even one of them move.

The second roof was done with ring shank and none moved at all.
Just because something has been done and has not failed, doesn’t mean it is good design.

If you didn't have the time or money to do it right in the first place, when will you get the time and money to fix it?

Offline Opc Patrick

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #10 on: April 30, 2009, 05:41:03 AM »
Hey! I know how to make it rain in Texas - just put OSB subflooring down.

Hey I am looking to build the same cabin you are   maybe closer to 20 X 34. So I will be watching this thread closely.  Anyway, If the OSB causes rain,  us Texans should be chipping in and paying for the rain.  Heck you could get you cabin paid for... :) 

Offline Zavoot

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #11 on: May 07, 2009, 07:31:38 PM »
Great idea - think I'll give it a try!
Where in Texas are you thinking about building?
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Offline phalynx

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #12 on: May 07, 2009, 07:38:08 PM »
I am about 95% done with my 1.5 story in Texas.  OSB is the only way to make it rain in TX.  Every time it starts to pour, I raise my coffee cup in the air and thank whoever is applying OSB.  I hate to be greedy but I need the rain.. :)

Offline Zavoot

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #13 on: May 07, 2009, 07:44:02 PM »
I spent a lot of time on your site before I started - incredible work!!!
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Offline Zavoot

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #14 on: May 07, 2009, 08:05:08 PM »
Finally back to some serious work - we had a few cloudy, semi rainy days but wet days meant the burn ban was finally lifted so a lot of the clearing that was done for the driveway and house got burned - throw in a trip to OKC for my daughters graduation from college  :) and a lot of time consuming little things - and well - back to building.

It was also very time consuming to finish all the diagonal bracing - decided to go with 3/8 x 6" zinc coated lag screws. (supposed to be fine with the new pressure treated wood). After a few rounds with a drill and ratchet - decided to get serious and borrowed my neighbors hammer/impact air wrench (and YES, I drilled all the 1/4" pilot holes 6" deep) - still there were 28 diagonals to install on 14 posts - and with 4 bolts in each diagonal - - - did I say it was time consuming - but I feel GREAT cause it is DONE! ;D

Since I am building right up into some trees I have to stop occasionally and trim a few limbs - this one caused a slight delay to repair some OSB!



Well I laid out the first section of wall using a 12' plate - - - Wow! raising 12' walls is a little different than 8's! :o
I left out the headers to make it lighter but it wasn't worth it - a pain to put in later - especially at 12' high.



Ok - got another section together (front door!) and put a bottom row of sheathing to keep everything lined up.
Couldn't resist getting going on the deck - wanted to get an idea of what it would look like by incorporating the live oaks into the design. It also helps with that sheathing too!

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Offline John Raabe

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #15 on: May 08, 2009, 09:04:01 AM »
What an interesting project.

Your suggestion about laying out the walls on the decking with 2x4s and walking around in it is a great bit of wisdom. A quick full scale mock-up. :D
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Offline Zavoot

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #16 on: June 15, 2009, 08:25:32 PM »
Well - finally back on track. Had some 'cash flow' jobs that took longer than I expected. But I've had a few days now and have finished framing the walls -
added the joists for the second floor loft and have the decking down
- also roughed in the stairs. The stairs are 11" treads and 7.7" risers and a full 36" wide.
I'm getting a couple of bids on framing the roof - - - when I see the bids I'll probably be motivated to building the trusses and setting them up myself ;D
And a shot of the view from the great room on the first floor.
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Offline Zavoot

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #17 on: June 23, 2009, 05:19:48 PM »
Roof going up - Ridgeboard with rafters. 12/12 pitch  :o Two four foot dormers on each side. Collar ties at 8' headroom. Will try to put part of HVAC up in that space and make a couple of ceiling access doors for storage (which is at a minimum in this plan!)




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Offline Zavoot

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #18 on: June 25, 2009, 04:29:16 AM »
The framing of the roof is finished - dormers done - eves done - just need to finish chimney chase and add the 7/16 osb decking - then the metal roof.
But I have a question if Mountain Dan or someone can help.
The plans call for joists in the open ceiling area on 4' centers. As you can see I have added collar ties to all the rafters in the open ceiling area and have removed 2 of the joists to be able to get scaffolding in to build the dormers. That means there is one joist left and it is on an 8' center (the room is 16' long). So . . .
Question 1 - do I really need to put the others back - it seems the collar ties and roof should be sufficient to keep the walls together?
Question 2 - If I do need to put them back - can I raise them up to 12' - they are currently in line with the other floor joists from the loft (which is 22' long - total cabin length is 38')?
Question 3 - Do I need ANY of these joists in the open ceiling area for structural purposes with the roof framing the way it is with the collar ties?



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Offline Sassy

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #19 on: June 25, 2009, 07:46:42 AM »
Really nice project, Zavoot!  You've gotten a lot done  :)  Glenn is down in the valley working today so won't be around until this evening.  MtnDon may be up at his cabin & doesn't have access to internet there. 

Is this one of John's plans?  You can ask questions in "Plan Support" if so...  but I'm sure someone will jump in here with help, soon - sorry I can't give any help  :(

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Offline Don_P

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #20 on: June 25, 2009, 09:00:26 AM »
It would take an engineer to say for sure, but my gut reaction is that with the dormer diaphragms and the raised ties you are probably ok. My opinion is worth every penny you paid.
The gable wall is not ok, it is overlooking a big reach of water and is misframed. The chimney will help and may be enough if you offset the sheathing to reinforce the hinge point. It should be continuously balloon framed from bottom to top with 1 stick, it has a hinge point now. I've nailed 2x6's sticking into the room 12"-16" scabbed onto the sides of the studs above the plate and double rimmed the inside edge with the longest stock possible lapping as far as possible then double wrapped the top and bottom of that "plant shelf" with ply with seams offset. Basically a horizontal box beam from wall to wall to stiffen that hinge. I've also mounted a solid sawn beam across that before. I've also stood steel plate up and made columns inside. You know your circumstances so its your call. Throw some more diagonals on the rafters till its sheathed in case a storm catches you. Looking good, looks like you got a raise too  :)

Offline Don_P

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Re: 20x38 1 1/2 story Comanche Texas
« Reply #21 on: June 25, 2009, 11:33:56 AM »
Ignore that previous poster, he's full of bull biscuits   d*.
The dormers are sitting on rafters, the rafter pairs are pinned at ridge and plate, the intersecting diaphragms aren't doing a thing to stop the spreading, in fact the dead weight of the dormers is causing more thrust. Put the ties back in. I can't tell for certain from the pics but dormers usually ride on double or triple rafters under each sidewall.