Peaceful Ambitions - 14 x 24 House

Started by Peaceful Ambition, March 20, 2017, 04:45:24 AM

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Peaceful Ambition

Correct, the jack studs weren't in yet when that pic was taken! Good looking out though, thanks.

So in laymans terms, does that mean I screwed the pooch again on these headers?  :o

Will the section modulous for this header as constructed realistically support anticipated loads or should I just bite the bullet and put in 2x10s?

Researching online is giving me some conflicting information,  ??? some tables are recommending 2x10's and others are saying 1 inch of header per foot of window span is sufficient for single story buildings?
You are not illiterate


Good question. Step back and figure out the load... look under "reactions", "max gravity" on the truss sheet for that area. How many trusses are bearing on that header? Multiply the number of trusses resting on that header by the max gravity reaction and that is the load the header is designed to support. So there is load.

For resistance, describe what the header is built of now and what is the clear span inside from jack to jack?

Peaceful Ambition

Ok, so i'm starting to see the idea here.

Truss A3 doesn't show me a gravity but I'm presuming it's the 1280 number.

The window with the most weight will have one attic truss and two scissor trusses sitting on it for a total gravity of 3936.
I imagine I would divide that in two (as only half of the truss is being supported by that wall) for a total gravity of 1968 lb over the one header

Now here is where I get a bit confused, I can't seem to find very much data on header strength, just spans and such for floors etc..
I know my math is off somehow, but I'm not sure how, because when I try to calculate psi I get..

Total bearing sq. inches per 2x6 = 1.5 * 72 = 108
Total bearing sq. inches over both 2x6 = 216

and when I plug that into 1968 lb (trying to get psi of force on the header) I get 9.1, but there is no way that can be correct otherwise I could build a header out of some rolled up newspaper.
Really trying to wrap my head around this, I suppose I just gotta pay my newbie dues for tackling a project like this with no experience.


Ok! take two, I've been thinking about this all day and it's killing me with the limited good weather we have left I'm not out there hammering! [waiting]

Hopefully I've got it right... I am scrapping the idea of lineal inches and PSI and going to lineal feet.

Here is what I have,

Pounds per lineal foot on the header = 1968 / 6 = 328 lb

I found a link which has WAY too much engineer-level vernacular for me to understand but what I DID find was that a single 2x6 #2 doug fir should be able to resist 347 lbs, per lineal foot. Doubled up that should be 694 pounds PLF.  ;D

So now I'm thinking the original 2x6 was more than enough, and despite mediocre strength gains from the added 2x4 underneath I should have more than enough support under full and realistic loads no?

[toilet] AHHH brainmelt.  [frus]

You are not illiterate

Peaceful Ambition

Alright so after doing some more research I'm pretty sure the 2x4 addition underneath the first header will be sufficient, it may not be as strong as a 2x10 header but after finally finding a link with some real numbers

I realized that under a MAX load (which is possible but not probable due to our roof pitch), our double 2x6 headers were shy by a mere 300 pounds. I'm not certain as to what two 2x4s can resist but I am sure it is over 300 pounds so with that information I feel comfortable moving ahead.

Next stop is the lateral bracing underneath and then sheeting! Woot! [cool]
You are not illiterate


This does demonstrate the reason for doing the planning and design work ahead of banging the nails.
Let's walk through it, you have one attic truss with a reaction AT THAT END of 1376 lbs plus 2 scissor trusses with an end reaction of 1280 lbs each =3936 lbs bearing on the header. You shouldn't have halved that load.

I used this beam calc;

Load- 3936
Span 72
width 3" (assumed 2 @ 2x6 header)
Depth 5.5
Fb 1200
E 1.4
Fv 135

Fail, section modulus required is 29.52, 2@2x6=15.125
Hmm, what is the Sm of 2@2x4, enter 3 x 3.5... 6.125

Add 15.125 + 6.125=21.250, you need 29.52, That's a fail.

Peaceful Ambition

You are not illiterate


The framer on the job I'm on forgot to include an overhang in an area where 3 different roof pitches intersect... we've had long strings of ****  :D.

When Dad would see me try to bull through a mistake he'd slow me down. "It's not that a good carpenter doesn't make mistakes, a good carpenter fixes them." I've found many more times than it should have taken that if I bull through I meet unintended consequences of the problem later.

The section modulus of a single 2x10 is 21.39 "^3. I'd pull the 2x4 and 2x6 from one face. Skim the 2x10 down to the same height as the remaining 2x4/2x6 height and reinstall. The 2x4 is 3.063, the 2x6 is 7.563, so a stacked 2x4+ 2x6 is 10.626"^3. Add that to the skimmed 2x10...

Well we're in this deep, we need to check the skimmed 2x10. I'm assuming your 2x4+2x6 stack height is 9", the 2x10 is 9.25" so you're ripping a quarter inch off the width (non code, you cannot rip a graded stick or the grade changes... use a pretty piece). By changing dimension section modulus changes
Sm= (bd^2)/6
     = (1.5x9x9)/6
     = ~20

With that and the 2x4+2x6 we're at ~30.7"^3, you need 29.52... Check

The sum of section moduli for two 2x4's+two 2x6's is 21.

Peaceful Ambition

Yeah good call don, thanks for jimmying a solution for us! That calculator is extremely helpful but mildly depressing when it doesn't say PASS lol.
Definitely gotta just pace myself and not let the incoming weather rush me.

Most likely I'm just going to pull the double top plate, pull the headers, put in the actual 2x10 headers, and re-trim cripples...
Looking everything over again made me realize those openings only had one jack stud per side anyway rather than two so I guess the upside is it will give me the chance to make that right also, and it's not like I don't have time to kill waiting on these trusses.

That calc also has me thinking now about my actual girders, which are two 2x8's sistered with a 1/2'' plywood piece in the middle and nailed to high heaven.
For the sake of that calculator, would that still be a 3 inch width or does the plywood make it a true 4? The span from post to post is 44 inches so when I plug that in for a 4x8 it looks pretty dandy at about 5200 lbs is what it can support. Obviously not much I can do about the girder size until I eventually put in some concrete but I'd rather be informed.

I have to admit it's a bit frustrating because it seems the closer I stick to the little house plans I bought (which brought me to this website in the first place) the farther I am from building a structurally sound building...
The plans instructed that the floor joists should be 2x6, that paired 2x8's and single trimmers were adequate for 6' headers on a 14' wide building with loft (which the numbers just don't support) and the recommended post foundation I'm using is widely considered to be a 'collapse mechanism'!

Were these accepted sizes before and code has just changed?  Are the plans inherently flawed? I'm feeling I just stop looking at the plans altogether since they only seem to be steering me to trouble?!  :-\

I digress, just grumpy today, anyway thanks for your help and anyone reading or researching remember I just made some mistakes so YOU don't have to!
Gonna be a busy week ahead. stay tuned folks!

Edit: Just remembered a question I had, when trying to figure out max grav on my side windows for truss A1 I need to add up all those smaller numbers along the bottom correct?
You are not illiterate


Darn, I hate it when the computer eats it  d*
I would enter the plywood padded built up beam as 3" x 7.25". Technically you can add the thickness of the individual veneers in the ply that run with the axis of the beam. Personally, if you have to count on veneer, here's your sign, use something bigger or stronger.

A! is identical to A2 as far as I can tell. it is capable of free spanning across the gable. You could look at it as the gable wall under it is not load bearing. I think the tech muffed the computer check on A1. The uniform support he has drawn under the truss should end on the right at 10, the wall, rather than at 9, the outboard end of the overhang.

Another way is to look at the highest inboard gravity reaction, 815 lbs down at joint 11 and 12, joint 13 is over the corner. "Load goes to stiffness". Although the truss can support the load without the wall, it would deflect about 1/4" overall at that joint. Since the wall under the truss will not drop that amount, the wall is stiff, it takes the load first. As the truss takes load and tries to deflect it lands on the wall. If the wall cannot resist the load it would deflect until the load lands on the corners and the truss is supported at 10 and 13. If things like cripples over a non-headered window rough opening begin to take load they would deliver it to the flat plate over the window, bow it, and you potentially have window trouble. A header is prudent. The load is not great, I'm not sure I trust his numbers but they are pretty close and I'm too lazy to dig real deep. I go pretty basic here. The door header is a double 2x10 under much higher loading. *I assume you are confirming rough opening requirements of the finish door*. If so it has established header height for that floor. So in that basic mindset, I make all the headers double 2x10. Unless the opening is greater than 6' or there is another load I then don't need to revisit each one and my job during framing is simpler. Typically with a stock stud, single bottom plate double top plate, a 2x10 header with a 2x plate on the underside is good for rough opening height... but do confirm with the actual millwork.

Edit, looking back at the truss sheets you posted, A4 is a frame rather than a truss, it is not self supporting, cannot span the opening, and delivers each of its' stud loads down to the wall below. It is working exactly as you were thinking. To check load on those headers add up the load from each stud above that bears on it. The double 2x10 should be fine there at 6' or under span.  I can't remember if this was discussed ignore it if we've been there, I would try to have those gable trusses dropped 3.5" for lookouts, vault the bottom chord of A4, balloon frame that wall, and cantilever the roof from 2' deep overhangs instead of 1'.

Peaceful Ambition

The door header as is with the 2x6s seems to pass all tests for that calc, it is only going to have one truss on it but even with two it still passes so I'll likely leave the door as is.
Am I reading it right that because the A1 Gable end is not going to be taking the entire force of the truss that the double 2x6 header is adequate there as well? It'd be great if I only had to re-do those two front windows.
And yeah we did mention the lookouts, those changes have been made but I just didn't upload all the new truss pics.

The A4 frame is sitting atop the wall on the downwind side of the house (A1 is where 90% of our big gusts come from). I'm not really sure how I can balloon frame the A4 wall now that it is already up and not balloon framed though I know it is a hinge, so I'm going to try and stiffen it with hardware, sheathing, and maybe that lvl, whatever I can really.
Is the A1 side going to need the same stiffening or does the collective resistance of all the subsequent trusses and blocking stiffen it enough?

You are not illiterate


The loft floor creates a deep horizontal beam that stiffens the A1 wall. That is a point of lateral support so it's fine to have a break there. 

Going to the hinge at A4. I'm coming up with about a ton of lateral from wind uniformly distributed along the hinge at the top plate.(4'x14' below the plate, 2'x14' above@25psf) A single 11-7/8" LVL or a 2 ply 2x12 at 14' span can resist that. (for the calc; design strength numbers for LVL are Fb 2800, E 2.0, Fv 280)

The key there is to attach that "plant shelf" well to the gable wall to collect the load (about 15o lbs per lineal foot along the beam, a nail is good for abot 75 lbs so at least 2 nails per foot from flat beam to top plate... double that) and then connect the ends very well to the braced side walls (1000 lbs). That is good connections at each end to the top plates and several blocks (in red) jammed in and nailed down well to transfer that load to the bracing side walls. The sheathing on those walls is well connected to the frame which transfers the load in the plane of those sheathed walls to the floor, which collects the entire structure lateral load and transfers to the girder, the braced foundation... and into adequate bearing with the ground.


Don--would a 2x6 run at a 45 degree angle from the center of where that plant shelf is, up to the bottom of the ridge pole do the same thing assuming it was attached properly?
Find what you love and let it kill you.


If the roof where it landed were stout enough to take the kick, not a truss, and if the plates are then sufficient as a horizontal beam at that halved span, dubious. But yes there are other ways to laterally support that hinge.  Don't create it in the first place would kinda top the list  :D. I've run a beam out to midspan from the loft before, it supported a stair landing bump but also helped stiffen the tall wall, so several ways, vertical posts would be another.

Peaceful Ambition

Holy smokes Don thank you so much for a visual model with that description! I am  enormously grateful you took the time to do that for us and I understand it clearly now!  Very exciting :D time to order an lvl!

As for an update, work has been a bit slow as we prepare things for an incoming winter storm this weekend. I recently found a website that sells used billboard vinyl, these are thick and strong and waterproof so I'll be stringing one up over the buildsite to try and keep out as much moisture as I can.

I've got the lateral bracing underneath completed and I finally got those headers replaced. What a pain that was, glad it's done although tomorrow I'm going to have to re plumb and square that wall as all the prying and banging knocked it around a bit!

Here's a pic from today

You are not illiterate


Brace well if you attach that sail or pond to the wall framing  ;)

Thinking about it, let me make a case for using 2 ply 2x12 with a filler of 1/2" ply. That would stack up beside the gable truss to the same height as its bottom chord. You can then lay a 2x6 plate on top of the plant shelf against the gable truss and scribe where their flat studs are. Notch your plate to fit round those and nail down the plate to both the beam and the truss (another tie, when I say in the post storm photos that this truss is laying on the ground at the base of that wall... it gets sucked out not blown in more often than not, the beam/connection has to work both push and pull, you could wrap metal lumber band straps around beam and truss easily at these thicknesses for that matter).

Those headers look good. On our job the guys are on day 4 of fixing the framer's attempt to reuse the old barn rafters, stringing, shimming, power planning, there is at least that much work to go  d*. My partner sent an email this morning  :D
QuoteA man who has committed a mistake and doesn't correct it is committing another mistake..... Confucius

Peaceful Ambition

Yeah that sounds great! I hadn't actually thought about the truss being 'pulled' out of position from the low pressure I had only been thinking in terms of push! And I still have some lumbers straps around so that sounds great!

This weather has come much earlier than typical, we even had an inch of snow the other day  [shocked](which melted now).

I started with just trying to put some house wrap over the top as that was all I had and storms were coming. But I found a website which lets you buy old billboard ads which are thick vinyl and ordered up a 20x30 for about 50 bucks. That sucker was HARD to get up and unfold on the roof, especially with only 1 ladder. But its been done!

Sheeting is going steadily, as of right now the house just looks like some kind of mysterious wooden cube cause I haven't cut out any of the windows yet :)

You are not illiterate


Yup ;)  Been there!  I was going out OFTEN to get the weight off as it always sagged in the middle.


I tried to find one that showed the ice and water that gathered on the tarp but this was November 1st 2009....

If you can get trusses up, even enough to 'tent' a tarp over the cabin I'd advise it.  If not then some kind of shed style arrangement to allow water and snow to sluff off the tarp would be good.

Peaceful Ambition

That picture is almost a spitting image of what we got going on. Even down to the non covered strip at the top of the walls! Thx for posting that.
Just been spending the last few weeks battling the weather that's been coming down on us, sometimes even going out every couple hours to try and knock some water off the top. Felt a bit like Lieutenant Dan screaming at the storm lol.

Trusses are FINALLY done and delivered today and we got some nice clear skies in the forecast for a bit, time to make the final push and get this sucker weathered in!

You are not illiterate


Good deal, could he not get up to set them on the wall tops?
Be careful around those overhanging nail plates as you move them around, they can tear you up.

Peaceful Ambition

Sadly no, we didn't have a big enough turnaround for the truck since they sent a full size semi so he had to drop them about 300 yards away and we just carried them up. On the upside, I got a discount on delivery because their standard is for 'plate level' delivery which they couldn't do. Found out about those little stabby suckers the hard way, hopefully once was enough to learn my lesson!  ;D
You are not illiterate


Well, how did the weekend go?  Did you get the trusses up?  I have a big scar near my right wrist from one of those plates! 

Since they are "attic" trusses, how big is the room that they make? 


Between those things and metal roofs and just construction my hands and arms are pretty decorated. I was having blood drawn and the nurse asked me if I cut myself. I said "all the time". "We can have someone come and talk to you about it" It was only then the light came on  :D "Not on purpose!"

Peaceful Ambition

Lol that's great Don!
Anyway we just started on them today, spent the weekend bracing everything a bit more and cleaning up  so it doesn't move out of square as we drag these suckers around, had some help come up today but they didn't get here until around 12 so it was kinda slow going, after tomorrow though I should hopefully have some much better progress and I'll post lots of pics!

These attic dimensions are off the top of my head but there is around 6' to 6'5 of headroom at the tallest point and the attic floor is gonna be 8' by maybe 10' or so. I'll get better numbers tomorrow. Like I said, it's more of a loft just for sleeping; bed, nightstand, and my lady, if we wind up feeling cramped we'll just use it as a storage space. Stay tuned!  ;D
You are not illiterate