Lumber Material Takeoffs

[cwailes]

I have a question about generating a material takeoff schedule needed for a roof plan. If I generate the roof framing model, when I click on a rafter, is the dimension given in the "Span" the correct measurement? If not is there a report that I can run that will give me the exact length of that rafter so that I can round it up and let the framer know the size of lumber he will need to make that rafter? I have noticed that If I go into a side view and measure the length of a rafter the measurement that I get compared to the "span" in the Object Info palette are way different. Any suggestion on this? Has anyone ever produced a material (lumber) takeoff schedule?

Edited May 26, 2012 by ccw

[taoist]

Span + Overhang / cos(36.67)

12'-9" + 2'-1" / cos(36.67)

153 + 25 = 178 / cos (36.67)

cos 36.67 =.80288

178 / .80288 = 221.7018

221.70108 / 12 = 18.4751' converts it to feet

.4751 * 12 = 5.7018 converts it to inches

.708 x 16 = 11.22 converts it sixteenths of an inch

Total rafter length is 18'- 5 11/16" (roughly)

This is for square cut rafters or for plumb ridge and square tail

You have a plumb tail so you need to account for that extra amount

In your case 5.5" rafter x tan (36.67)= 4.0950 inches

tan (36.67) =.7445

Add this 4.0950 inches to your 18'-5 11/16" = 18'-9 11/16".

Edited May 26, 2012 by taoist

[cwailes]

Is there a way to set this up in a report so I can easily access this information for future projects?

[taoist]

ccw,

I do not know any of the trig functions in VW Worksheets.

I do not use VW for material takeoffs.

I am sure there are others that could answer this for you.

[cwailes]

Thanks taoist, I will keep checking back. I am sure someone has to have run across this before and will also keep searching the forums for this question. Just in case someone has already answered this before.

[cwailes]

Taoist I have a question. I am trying to set up an excel formula so that I can have these values calculated easily. If I do the Cosine of the pitch (36.67) on my calculator it gives me .80208845. However, if I do it in excel or look it up on the web the cosine of 36.67 equals .515580058. So which one is correct? Does anyone else know why I am getting two different numbers?

[cwailes]

I figured it out. Excel and Open office do calculations in "Radians" and not degrees. So you have to manually input the cosine of the pitch. For all of you who need this information for you roof take offs, If you would like the file, I have an open office spread sheet with the formulas already done, just let me know you email address and I will send it to you. Be sure you convert you span and overhang into inches first. You will then need to use a calculator to get the cosine of your pitch and input that number into the "COS of Pitch" column. Your end result is the length of your rafter in feet. Sure wish this could be done easier in VW.

[taoist]

To find degrees when pitch is known.

In Excel you use DEGREES(ATAN())

Roof pitch say is 9. This assumes common rafters.

What is the degree of slope?

9/12 = .75 Rise over run or tangent function.

Opposite side over adjacent side

DEGREES(ATAN(9/12))= 36.87 degrees

COS(36.87*PI()/180)= 0.799998928

To find rafter length:

Rafter run / cos (36.87)

Example: 12' span + 2' overhang = 14' span

14' / cos(36.87*PI()/180) = 17.5'

To cross check;

Pythagoras 144+81=225 SQRT 225=15

12 squared + 9 squared = 225

Square root of 225 = 15 per foot run of 9 pitch common rafter

15*14=210

210/12=17.5'

Have fun

[Christian Fekete]

Have you tried the frame roof option? I believe it gives a breakdown list of materials

[taoist]

Followup.

 

Snapshot of how to use custom report fields to get what you want.

 

Need to convert roof slop to pitch if required.