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Construction Math For Dummies

 
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Old 03-09-2019, 09:15 AM   #1
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Construction Math For Dummies


I'm about to start cutting the driveway for this one in a couple weeks and have been going over the prints for a month or so trying to familiarize myself with all of the peculiar details.

As I was working my way through the framing, I ran into a math problem way to complicated for my puny brain.

I had a solution after one conference call with the architects, but I brought my two leads into my office for an afternoon and had them chew on it as an exercise.

One of them is a VMI grad and actually worked pretty deep into the equations, but was stymied by missing information on the prints.
The other has a degree in Classical Guitar....and just stood there looking dumber than me....which was not an easy task.


I'm wondering......without the use of the CAD files, how would you guys do this?

The ridge beams are skewed at irregular and differing angles from the exterior walls at each individual "pod".
Due to the non-perpendicular orientation, you end with sloped exterior wall heights.

How do you guys frame this thing?
How do you generate the stud lengths?
Ascertain the exact angle of slope for the walls (bevel cuts)?

I know I would have had to simply guerrilla that thing after I got the deck built with complete mathematical perfection.
Pythags....plumb sticks/bobs.....lasers.....some free jazz....and I'm not even sure what.
But I could get it done.
Seems like that would take an incredible amount of time.

I understand the values necessary to generate the answers using equations.....
Angle of the ridge beams.
Perpendicular distance from the ridge beam to certain key points (corners....etc.).
Distance from sub-floor to underside of ridge.
I just have no concept of what equations to use.

Forget about where the roof line meets the radiuses.....
I would be pulling my hair out.

Is there an easy(ier) way?
How would you do it?
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Old 03-09-2019, 10:16 AM   #2
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Re: Construction Math For Dummies


Odd angles like those studs I like to draw out on 3d graph paper so I can see what is going on. Draw the stud, then the roof plane intersection. You can use that diagram to set up the trig calculations without getting too lost.

Or you can go old school and direct measure off your diagram what the xyz difference is. It's like doing rise and run, except with the added slope on the cut. Set your saw up directly based on those, or do the trig to convert to saw angles.

If you don't have graph paper, you can just draw the axis on a sheet of paper or on the subfloor. A large drawing is good.

You can also just dummy one small section of roof and stud up and direct measure with an angle finder.


You can also do it with a steel square....

Stud lengths are easy, because it's the same as normal once you convert the roof run and rise to the specified angle.

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Old 03-09-2019, 10:17 AM   #3
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Re: Construction Math For Dummies


Man, how do you even begin to price that thing?

If it were my job, I’d put that thing into sketchup and have it on my site laptop.
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Old 03-09-2019, 10:29 AM   #4
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Re: Construction Math For Dummies


Obviously, dummying up and direct measuring is the fastest. Short of plugging into equations.
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Old 03-09-2019, 10:34 AM   #5
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Re: Construction Math For Dummies


Quote:
Originally Posted by hdavis View Post
Odd angles like those studs I like to draw out on 3d graph paper so I can see what is going on. Draw the stud, then the roof plane intersection. You can use that diagram to set up the trig calculations without getting too lost.



Or you can go old school and direct measure off your diagram what the xyz difference is. It's like doing rise and run, except with the added slope on the cut. Set your saw up directly based on those, or do the trig to convert to saw angles.



If you don't have graph paper, you can just draw the axis on a sheet of paper or on the subfloor. A large drawing is good.



You can also just dummy one small section of roof and stud up and direct measure with an angle finder.





You can also do it with a steel square....



Stud lengths are easy, because it's the same as normal once you convert the roof run and rise to the specified angle.

Drawing it on the floor is how I would have done it without the CAD files.

Every ridge to wall angle is different.

And the main issue is finding stud heights at any given point.

Iím going to get a list of key points for the architect to generate off of CAD.

Iím thinking I will need all of the corners...
And the points when the radius begins on each wall.

Then I theoretically should be able to frame all the walls, and just frame the roof to the walls.
If anything is off though....it could get messy.
Never used CAD points before, but I think it should be fairly simple using them.

Next issue...
Not having to field measure every rafter.
Generating numbers based on layout.

Then thereís the arched section between the ridges.
Thatís easy though.
Make a pattern....go.....


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Old 03-09-2019, 10:36 AM   #6
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Re: Construction Math For Dummies


Quote:
Originally Posted by CENTERLINE MV View Post
Man, how do you even begin to price that thing?

If it were my job, Iíd put that thing into sketchup and have it on my site laptop.
I'm using an archaic version of TurboCad and there are many times I use it in the shop just to figure an angle or length of piece of wood to be cut.
It would take me two forevers to try to do it without some "computerized" help. Geometry and the equations and I aren't the best of friends.
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Old 03-09-2019, 10:39 AM   #7
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Re: Construction Math For Dummies


Quote:
Originally Posted by CENTERLINE MV View Post
Man, how do you even begin to price that thing?

If it were my job, Iíd put that thing into sketchup and have it on my site laptop.


Cost Plus 15.

Thatís how.



I just threw a pretty heavy square foot number on the framing.

I think
My estimate is around $325 per square ft. for the whole thing.

Estimate...key word.


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Old 03-09-2019, 10:42 AM   #8
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Re: Construction Math For Dummies


Quote:
Originally Posted by Robie View Post
I'm using an archaic version of TurboCad and there are many times I use it in the shop just to figure an angle or length of piece of wood to be cut.

It would take me two forevers to try to do it without some "computerized" help. Geometry and the equations and I aren't the best of friends.


Problem is....
Computers and I ainít the best of friends either.

Iím just going to have the architects do their jobs and generate everything I need.

Iím thinking that Iíll need to check everything first somehow......just to be sure they didnít screw up a value.
Like plotting to underside of double plate...or top.
That kind of thing.

Itís gonna be a ride no matter what.


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Old 03-09-2019, 10:44 AM   #9
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Re: Construction Math For Dummies


Quote:
Originally Posted by BlueRidgeGreen View Post
Problem is....
Computers and I ainít the best of friends either.

Iím just going to have the architects do their jobs and generate everything I need.

Iím thinking that Iíll need to check everything first somehow......just to be sure they didnít screw up a value.
Like plotting to underside of double plate...or top.
That kind of thing.

Itís gonna be a ride no matter what.


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I'd hire Warren....
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Old 03-09-2019, 10:47 AM   #10
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Re: Construction Math For Dummies


Quote:
Originally Posted by Robie View Post
I'd hire Warren....


No offense to Warren....
But me and my boys got this.

Iím doing it because itís interesting.
I blew off a few much easier customs to take it.
Certainly not going to let someone else have the fun.


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Old 03-09-2019, 10:47 AM   #11
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Re: Construction Math For Dummies


If you have the CAD files, you dump it into your CAD program and you just pull all the numbers off of that.

Honestly, the stud lengths are the easiest part. Figure the roof run at the wall angle, then it's like cutting any run and rise wall intersection.
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Old 03-09-2019, 10:54 AM   #12
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Re: Construction Math For Dummies


Quote:
Originally Posted by BlueRidgeGreen View Post
Cost Plus 15.

Thatís how.



I just threw a pretty heavy square foot number on the framing.

I think
My estimate is around $325 per square ft. for the whole thing.

Estimate...key word.


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DAMN! Iíd have a hard time building a simple cape out here for $325 finished. That place would be double or triple that figure out here.
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Old 03-09-2019, 10:59 AM   #13
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Re: Construction Math For Dummies


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DAMN! Iíd have a hard time building a simple cape out here for $325 finished. That place would be double or triple that figure out here.


Yeah...
I hear that.
Different market here.
Simple cape ďcouldĒ be built for 150 here.
Not by me.
But itís done.

I should get close to my number.

We are going to do almost everything in house.
Time is not a factor.


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Old 03-09-2019, 11:01 AM   #14
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Re: Construction Math For Dummies


Quote:
Originally Posted by hdavis View Post
If you have the CAD files, you dump it into your CAD program and you just pull all the numbers off of that.



Honestly, the stud lengths are the easiest part. Figure the roof run at the wall angle, then it's like cutting any run and rise wall intersection.


Yeah....
And thatís where we ended up in the office.
Those equations.
But without knowing the ridge to wall angle, or even the exact ridge placement,...the numbers would be useless.

(When I say ďweĒ....I mean Chad. )


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Old 03-09-2019, 11:04 AM   #15
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Re: Construction Math For Dummies


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Originally Posted by CENTERLINE MV View Post
DAMN! Iíd have a hard time building a simple cape out here for $325 finished. That place would be double or triple that figure out here.


Ha!!!!

Just checked.

Youíre on the Vineyard.

Iíve did a couple kitchens up there for my Manhattan clients back in the old days.

$$$$$$$$$$$$$$$$$$$$$$$$$

You are no longer allowed to comment on pricing in the real world.


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Old 03-09-2019, 11:34 AM   #16
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Re: Construction Math For Dummies


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Ha!!!!

Just checked.

Youíre on the Vineyard.

Iíve did a couple kitchens up there for my Manhattan clients back in the old days.

$$$$$$$$$$$$$$$$$$$$$$$$$

You are no longer allowed to comment on pricing in the real world.


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Ya, stupid money out here. They have it but hate spending it. Iím just about to begin building a porch with a balcony above on a $7 million house and they canít figure out why my price is so high...
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Old 03-09-2019, 11:47 AM   #17
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Re: Construction Math For Dummies


That **** hurts my pretty little head.
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Old 03-09-2019, 11:53 AM   #18
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Re: Construction Math For Dummies


Quote:
Originally Posted by BlueRidgeGreen View Post
Yeah....
And thatís where we ended up in the office.
Those equations.
But without knowing the ridge to wall angle, or even the exact ridge placement,...the numbers would be useless.

(When I say ďweĒ....I mean Chad. )


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I've pulled those off the scale drawing before. Better to have actual measurements, especially in this case.
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Old 03-09-2019, 12:02 PM   #19
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Re: Construction Math For Dummies


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I've pulled those off the scale drawing before. Better to have actual measurements, especially in this case.


I could just set those values myself and roll on.

Angle of ridge to wall.
Exact placement.

But only if I did the calcs.

Thatís what Iíd do if it were pre-CAD.


Using their CAD figures for anything binds me to them fully.


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Old 03-09-2019, 05:23 PM   #20
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Re: Construction Math For Dummies


I think the most important thing is to see if you can a hold of the
Architect and beat the holy **** out of him.

That is where I would start anyway.

Andy.

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