Author Topic: North Arkansas 20x24 A-Frame  (Read 672 times)

0 Members and 1 Guest are viewing this topic.

Offline tsmith09

  • Newbie
  • Posts: 2
  • Welcome to the CP-Forum
North Arkansas 20x24 A-Frame
« on: March 31, 2020, 04:04:42 AM »
Hello! Long time readers, first-time posters. A few years ago, we purchased about 20 acres in northern Arkansas that is next to my father’s land. We have constantly been trying to figure out what we wanted to build and how best to go about it. After much discussion, we have decided to build an A-Frame.

Our first step is going to be getting the gravel for our driveway which should be happening by June. While we wait on that we are planning and will start buying materials for the foundation piers. We are using the plans attached to go about our build. With these plans, the a-frame rafters are connected directly to the concrete footers with what appears to be L shaped brackets. We are trying to figure out the best way to slope the concrete footings where the brackets will be embedded, and we are also thinking that these might be better to use than the L shaped brackets. Specifically, the CB5-4.5 that was recommended by a representative at Simpson strong tie to connect two 2x6 rafters as the plans call for.

Curious if anyone has used these brackets before or have had to slope concrete footings for these brackets. If you have any suggestions or know of something that’s better to use, we would appreciate any advice.
 
Thanks,
The Smith's












Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,550
Re: North Arkansas 20x24 A-Frame
« Reply #1 on: March 31, 2020, 07:32:25 AM »
I'm sure others will post with the downsides of an A frame, those are real. The useable width of that 20' wide is about 14'.

I'll speak to the foundation. That is insane!  :D
18 piers 4' oc of those dimensions, exposing the rafter tails requiring treated and special connections at each pier... 1963, I didn't know they were smoking crack back then.
It will be cheaper, faster and stronger to pour a continuous footing under the main floor footprint and build a block crawlspace. Install a 2x8 treated mudsill, install joists with ends cut at the roof angle and then erect the rafters from the mudsill. No exposed framing so no need for treated other than the mudsill, no special connections, everything will stay in plane, with those piers if you do happen to get it right at installation, it will likely not remain so over time, all of that soil line is disturbed.

Offline MountainDon

  • Administrator
  • Journeyman
  • *****
  • Posts: 16,875
  • Jemez Mountains, NM; that's pronounced HEY-mess
    • My 15.75 x 30 Jemez Cabin
Re: North Arkansas 20x24 A-Frame
« Reply #2 on: March 31, 2020, 12:58:32 PM »
What Don_P said.

I cannot imagine placing 18 piers, with angled tops at precisely the correct position and spacing and tilt. 

Plus, 2x6's don't provide sufficient space for insulation. Back when that was drawn it was common to have little to no insulation, not good for today, even for part-time recreational use.

Most of AR has a shallow frost depth. A roto-tiller can be used to loosen the dirt and then use a square nosed shovel to remove the dirt and form the footing trench. That way the rebar reinforced footing is a monolith, much stronger than 18 separate piers that can and will move independently.

Just because something has been done and has not failed, doesn’t mean it is good design.

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,550
Re: North Arkansas 20x24 A-Frame
« Reply #3 on: April 02, 2020, 03:19:33 AM »
Fabricating EXACT duplicate frames and then dragging them into place, tipping them up and bracing them is something that also needs to be thought through. I've seen and been involved with failure to think through just about every aspect along that path  :D

That said this is another tilt up rigid frame from that period. This is from an APA publication from 1962, now out of print but I do have Dad's design manual. It can be built with sloping or vertical walls but does enclose more useable space per footprint area, sorta the predecessor of Socket Systems, and actually better structurally.


Offline tsmith09

  • Newbie
  • Posts: 2
  • Welcome to the CP-Forum
Re: North Arkansas 20x24 A-Frame
« Reply #4 on: April 02, 2020, 03:49:26 AM »
Thank you both for the advice. We appreciate it. It does confirm what we were thinking and we will look for more modern building plans and strategies. We will let you all know what we find and come up with. 

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,550
Re: North Arkansas 20x24 A-Frame
« Reply #5 on: April 02, 2020, 06:42:39 AM »
Conventional construction is conventional for a reason, it generally offers the most bang for the buck while respecting good engineering practices. Platform framing is pretty simple, adaptable and strong. A very common stock truss is the 24' wide 4/12 Fink type they make for fast, easy, cost effective roof construction. A 24' wide building with a center row of piers and girder within a crawlspace foundation can be spanned by 2x8's, another cost effective size. IMO that building width is where stairways begin to work well within the interior layout if you need a second floor, you may well not need to think "up" if the size of that A frame was adequate.

It might be worthwhile to look at interior floorplans and sketch out what you think would work well and throw that out to the group here for comments/modifications and then back into the structural aspects from there. What I see all to often is someone will find a plan and "buy into" it and when they post it one look shows that it was designed by someone who really was not qualified or knowledgeable in how things should be built. At that point they are really seeking confirmation on their choice and folks that do know how to build are thinking and saying NOooo! It is not particularly hard to build well but it seems that there are more ways to try to cut corners that will inevitably come back to haunt someone than I had ever imagined prior to the internet.

 

Templates: 5: index (default), Ads (default), Portal (default), Display (default), GenericControls (default).
Sub templates: 12: init, html_above, adsheaders_above, body_above, adsindex_above, portal_above, main, portal_below, adsindex_below, body_below, adsheaders_below, html_below.
Language files: 3: SPortal.english (default), index+Modifications.english (default), Ads.english (default).
Style sheets: 1: portal (default).
Files included: 38 - 1132KB. (show)
Cache hits: 12: 0.00149s for 40,878 bytes (show)
Queries used: 29.

[Show Queries]