[wallmaxx]

I’m enjoying this Wallmaxx, years ago, in an attempt to be a more efficient framer, I made these little charts and laminated them.
Along with a $4.00 calculator I got pretty good at generating cut lists, ridge props, ridge lengths, etc.
It took many nights of studying trig- which I hated- but it made me a better roof man
I would mark on the subfloor before the walls went up where each ridge started and stopped, ridge prop lengths and locations, ridge to ridge hips and valleys, etc
The guys could see in 2 dimensions what my cut pile would end up being in 3 dimensions
Now a construction master has replaced my cheat sheets- but that’s okay-time marches on View attachment 488951

View attachment 488953

That's awesome. Thanks for sharing!!

I love hearing stories like yours. It's always great to meet people who have drive and initiative to go above and beyond. There is something rewarding about pushing for excellence.

I just bought Sim Ayers book, the Holy Grail of Roof Framing Geometry & Trigonometry exactly because, before I complete life on this planet, I want to expand my understanding of complex roof framing. It's fun.

 

[wallmaxx]

Here are some roof types I have framed. I only focused on the ones I actually needed to build so I know there are many more other types out there. Let me know and I'll add them to the list.

 

[wallmaxx]

Forgot the parapet roof for an apartment I did in Oak Harbor WA. I met the most organized PM ever on that project. The guy was a genius at scheduling and staging.


Now....we can start with calculating all of these roof types.


This is fun because I created equations in RPN for my HP50G calculator originally, so I'm having to "learn" the steps in BuildCalc or my Construction Master to get the answers.


Then again, if you use a good CAD application and draw everything with exact, real-world sizes, you can get most of these calculations from the CAD app and they will be correct.

 

[wallmaxx]

some 3D roof labels

 

[wallmaxx]

Main common rafter:

 

[wallmaxx]

more:


Something I noticed way back in the 90s was that CM doesn't figure out jack lengths correctly with regard to the sloped angle of half of the hip.


I wrote them back then....nothing. This is where using a programmable calculator can be more accurate.

 

[wallmaxx]

So now here is a list of all the things I've run across where I took the time to write an RPN equation to solve.

Programming the equations is nice because the app can be written to "ask" for information, rather than me having to remember all those steps, and writing things down half way.....:blink:

I'll start by saying I don't know how to do all these things using BuildCalc or Construction Master, so it will take a bit to figure some of the more complex things out.

The HP calculator has variable storage buttons with 5 character labels so that's why I used the "odd" naming labels.

 

[wallmaxx]

P1PL2

COMMON PITCH / 2 DIFFERENT PLATE HEIGHTS
Solved using a construction master calculator or BuildCalc App

 

[wallmaxx]

P2pl1

As always...check for errors. If I messed up something let me know and I'll correct it.

The Two Pitched roof on a common plate (P2PL1)

 

[wallmaxx]

So I'm trying to get an Excel equation to do this RPN action:



DO N D N - 'D' STO
UNTIL D 0 ≤
END


It's a DO - UNTIL - END string.


It takes an increment length (N) and subtracts it from (D) then re-saves it over the original (D) and continues subtracting (N) from the ever reduced (D) until it reaches zero.


It does this:


Say you have a 2' increment (N) and your longest jack is 12' (D)


12' - 2' = 10' (export to the stack and re-save as D)
10' - 2' = 8' (export to the stack and re-save as D)
8' - 2' = 6' (export to the stack and re-save as D)
6' - 2' = 4' (export to the stack and re-save as D)
4' - 2' = 2' (export to the stack and re-save as D)
2' - 2' = 0' (export to the stack and re-save as D)
END


The list generated is:
10'
8'
6'
4'
2'
0'


This is how I can calculate jack rafters in RPN and if I can get this into excel, I'll post a spreadsheet that should help calculate most hand cut roof systems. This is the only headache I have been unable to figure out.

 

[wallmaxx]

 

[Texas Wax]

So I'm trying to get an Excel equation to do this RPN action:



DO N D N - 'D' STO
UNTIL D 0 ≤
END


It's a DO - UNTIL - END string.


It takes an increment length (N) and subtracts it from (D) then re-saves it over the original (D) and continues subtracting (N) from the ever reduced (D) until it reaches zero.


It does this:


Say you have a 2' increment (N) and your longest jack is 12' (D)


12' - 2' = 10' (export to the stack and re-save as D)
10' - 2' = 8' (export to the stack and re-save as D)
8' - 2' = 6' (export to the stack and re-save as D)
6' - 2' = 4' (export to the stack and re-save as D)
4' - 2' = 2' (export to the stack and re-save as D)
2' - 2' = 0' (export to the stack and re-save as D)
END


The list generated is:
10'
8'
6'
4'
2'
0'


This is how I can calculate jack rafters in RPN and if I can get this into excel, I'll post a spreadsheet that should help calculate most hand cut roof systems. This is the only headache I have been unable to figure out.

Might try a if then function. If previous two cells subtracted is than 12(") return ' ' (blank cell). If not perform function for next jack. Run 5 cells with just the jack function, then run 10-15 with the If then formula. Should get blank cells after the last jack is less than 12", in theory.

Did not try this exactly. But have used it in complex spread sheets for calculating cabinetry material and not have calculated results were there were no number of unit entries, kind of gig. If that makes sense.

 

[wallmaxx]

Might try a if then function. If previous two cells subtracted is than 12(") return ' ' (blank cell). If not perform function for next jack. Run 5 cells with just the jack function, then run 10-15 with the If then formula. Should get blank cells after the last jack is less than 12", in theory.

Did not try this exactly. But have used it in complex spread sheets for calculating cabinetry material and not have calculated results were there were no number of unit entries, kind of gig. If that makes sense.

I think the part that was stumping me was how to make it stop when it hits zero or a negative number but if I create enough cells to cover the maximum possible number of Jack rafters then I would just have to know that when the number becomes negative that’s not something I would be cutting in reality. I think that would work. Thank you. I’ll let you know what happens.

 

[wallmaxx]

yesssssss

the numbers in GREEN are variables.

• Jack 1 is a custom length determined by such things as Ridge and Hip Thickness.
• The remaining Jacks are determined by subtracting the Increment amount from Jack 1 (saving as Jack 2) then subtracting the increment from Jack 2 (saving as Jack 3) and so on, continuing to >= zero.

I can make 20 or 25 rows for jacks (I don't think I've ever cut a roof with more than 20 jacks on a hip or valley) so this should work.

 

[Mcjarod]

How would you guys frame what I call a compound rake wall??

meaning both the bottom and the top are sloped,

the numbers I have to work with are a run of 20’, 2.29° drop on the bottom, 2/12 on the top, and a short side height of 8’10

This is what it’ll look like later on

 

[wallmaxx]

I'd need the location of the door and window to be 100%.
Just all studs...see attached. That's how I would do it. Sloped bottom is odd.

 

[Mcjarod]

How I had ended up doing them was with the construction calculator in one method, completely precutting the entire thing windows and doors too, and the other method which ended up being fastest was simply calculating the two end studs and then nailing off the entire top plate and running the bottoms wild but set on layout, then snapping a line and cutting them all

 

[wallmaxx]

How is the floor sloped like that? Is it on a “flat” roof or something?

 

[Mcjarod]

Yea, it’s a sloped roof system with a roof deck framed over it, I’ll attach the split elevation.