Author Topic: Can I change the Little House plans to 16x24?  (Read 393 times)

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Offline maggiethecat

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Can I change the Little House plans to 16x24?
« on: January 08, 2022, 11:53:01 PM »
Hi everyone, I was wondering if we could build the 14x24 little house as 16x24. Will this be alright? Thanks in advance!
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Offline MountainDon

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Re: Can I change the Little House plans to 16x24?
« Reply #1 on: January 09, 2022, 05:27:28 AM »
Floor joists, ceiling joists, and rafters may have to be increased in depth or spaced closer together, as well as being longer of course.
Just because something has been done and has not failed, doesn’t mean it is good design.


Offline maggiethecat

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Re: Can I change the Little House plans to 16x24?
« Reply #2 on: January 09, 2022, 05:44:36 PM »
Floor joists, ceiling joists, and rafters may have to be increased in depth or spaced closer together, as well as being longer of course.

Thank you Don, is there a formula for this?
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Offline MountainDon

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Re: Can I change the Little House plans to 16x24?
« Reply #3 on: January 10, 2022, 05:17:27 AM »
There are tables in the IRC and google can find others.
https://codes.iccsafe.org/content/IRC2021P1

The AWC Span Calculator is very handy
https://www.awc.org/codes-standards/calculators-software/spancalc
There is an Android and iPhone version available too. Links to them in the above page IIRC.

The AWC tutorial page explains use of the tables and the values used in the calculator.
https://www.awc.org/codes-standards/spantables/tutorial

Well worth becoming familiar with.
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline maggiethecat

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Re: Can I change the Little House plans to 16x24?
« Reply #4 on: January 13, 2022, 09:00:17 PM »
Thank you Don, I wonder if the number of piers and their positions would stay the same?
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Offline Don_P

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Re: Can I change the Little House plans to 16x24?
« Reply #5 on: January 15, 2022, 02:43:57 AM »
This is the foundation chapter of the code. Section 403.1 should answer that part of the design;
https://codes.iccsafe.org/content/VRC2018P1/chapter-4-foundations

Offline maggiethecat

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Re: Can I change the Little House plans to 16x24?
« Reply #6 on: January 15, 2022, 02:45:31 PM »
Hi Don, I couldn't find anything about it in that link, but I found this old thread: https://countryplans.com/smf/index.php?topic=14482.0

It had the following image, which I think is probably a good idea for the spacing:


I would need to build up the beams from three 2x6's. The difference is that in the little house 14x24 plans, the floor overlaps the posts by 2'2", probably so you can add skirting. These plans have the posts at the very corners.

I'm not sure where to go with these, I thank you for suggestions!
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Offline Don_P

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Re: Can I change the Little House plans to 16x24?
« Reply #7 on: January 16, 2022, 05:16:48 AM »
Prescriptively, that is, without an engineer or architect's seal, these are the minimums. If you wish to step outside of these provisions, be prepared to engage one of those registered design professionals.

For what you have pictured above the answer is ;
Quote
R404.1.9.3 Masonry piers supporting braced wall panels.
Masonry piers supporting braced wall panels shall be designed in accordance with accepted engineering practice.

In other words, engineer required.

So going back to the easy way,

This is section R 403.1
Quote
R403.1 General.
All exterior walls shall be supported on continuous solid or fully grouted masonry or concrete footings, crushed stone footings, wood foundations, or other approved structural systems that shall be of sufficient design to accommodate all loads according to Section R301 and to transmit the resulting loads to the soil within the limitations as determined from the character of the soil. Footings shall be supported on undisturbed natural soils or engineered fill. Concrete footing shall be designed and constructed in accordance with the provisions of Section R403 or in accordance with ACI 332.

Using the tables below that section, it looks like a 6x14 concrete strip footing would be about the minimum.

The foundation walls, refer to section 404;
Quote
R404.1.2 Design of masonry foundation walls.
Masonry foundation walls shall be designed and constructed in accordance with the provisions of this section or in accordance with the provisions of TMS 402. Where TMS 402 or the provisions of this section are used to design masonry foundation walls, project drawings, typical details and specifications are not required to bear the seal of the architect or engineer responsible for design, unless otherwise required by the state law of the jurisdiction having authority.

The easy way is 8" block, check the reinforcement schedule there.

For cantilever spans see table R 502.3.3(1)

For girder spans check table R602.7(1) and (2)
In the second table they address the doubled 2x8 girders across the floor supporting the 2x6 floor joists. There's room to interpolate and play but you are either a ply or a size too light.




Offline Don_P

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Re: Can I change the Little House plans to 16x24?
« Reply #8 on: January 23, 2022, 03:57:54 AM »
This is non prescriptive but is using methods that I believe an engineer could seal if the building inspector required it. The posts rise from large piers (overturn resistant wide). The posts rise, unbroken from pier to top wall plate. The wall sheathing provides bracing for the posts. This is "post frame construction". At 16' wide you can make it with 2x12 joists and no mid girder or piers. That can be done either way, weigh foundation costs vs bigger framing costs.

Hmm, image isn't posting for me, this is where I've put the file;
http://timbertoolbox.com/cp/16x24postframe.jpg

Saw another pic while filing that. This is a 16x28 we built a couple of years ago. We sawed all the framing, floor and roof sheathing and siding for this job. It is on a full basement which put the washer/dryer, water heater, heater, etc down there.
http://timbertoolbox.com/cp/PatSE.jpg
« Last Edit: January 23, 2022, 04:30:29 AM by Don_P »


Offline Don_P

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Re: Can I change the Little House plans to 16x24?
« Reply #9 on: January 24, 2022, 10:59:47 AM »
It looks like I'm talking to myself. So to continue a conversation with the smartest man I know.
This is a perspective view from my first plan attempt.
timbertoolbox.com/Pat/PatPierFnd.jpg

This is non prescriptive but goes a long way to meeting the intent of the foundation requirements in the code. There is a braced "core" that anchors the building and through the floor diaphragm, the piers that support the rest of the structure. I have built this and it works. I wouldn't do it there there are high winds, seismic, etc. In this particular instance the building official chose to require an engineer if we went that route.

The quick calculus in my head was to think about whether it was smarter to hire the engineer to say I was right. Or, would that cost about the same as putting in a full basement.

Here's what we built;
timbertoolbox.com/Pat/patrick6.18.jpg

and a good bit of the rough framing exposed in this shot
timbertoolbox.com/Pat/patricksframe.jpg
The end rafters are not in yet. count from the right hand rafter going left, you have a good sightline on rafters 3 &4. trace them down to the wall, notice they "stack" directly over the wall studs. You cannot see the 16' floor joists on the main and loft floors but they are also in exactly the same plane as the rafters. Everything "stacks" wood on wood over wood whenever possible.

Ahh, my feet have finally returned, off to the shop.

Offline MountainDon

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Re: Can I change the Little House plans to 16x24?
« Reply #10 on: January 24, 2022, 03:25:24 PM »
Hmmm.. The smileys have disappeared. ???  I have the keystrokes for that one memorized....  The icons for them are not displaying; that needs to be addressed.
"Thumbs Up" to Don_P

« Last Edit: January 24, 2022, 04:28:41 PM by MountainDon »
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline MountainDon

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Re: Can I change the Little House plans to 16x24?
« Reply #11 on: January 24, 2022, 04:30:42 PM »
;D   :)   :(   ;)
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline Don_P

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Re: Can I change the Little House plans to 16x24?
« Reply #12 on: January 24, 2022, 04:46:26 PM »
Smiley's, tags, its all gone here.

Knowing our driveway, you'll get a kick out of this. We had a pretty good snow a week ago. With Michelle still not 100% after knee and hip work, hiking in snow was out. I had already made backup plans. This is my email to my Sis.

Trying manual entering quote tags
Quote
We got Michelle down to the road and off to work today. I got plowed out and back up to the house, ran a load down to her car and came back up for her. ZZ Top was playing the "How how how" song as we loaded her on the armrest of the dozer, I spun it around and presented the sorta plowed 30% grade. "Have Mercy" left her lips, and away we went  :D

edit; Well, that worked at my end, trying img tags, I had no joy on this the past 2 days

Sawed these posts out last week for a shed, one is a corner post the other a midwall post.  Horizontal boards will stack in the grooves.

Hmm, still no joy there. The tags and img link are all here in the reply window but nothing in the viewed thread. That's what I keep getting.
« Last Edit: Yesterday at 04:46:04 AM by MountainDon »