# Roofing take offs from blueprints



## bkb0000 (Feb 1, 2009)

howdy

i've been a roofing contractor for about 5 years now. i can do take offs on physical roofs blind-folded, obviously (anybody with a brain should be able to) but have a hell of a time when it comes to blue-prints.

i've come across a few different types.. but i've noticed that GENERALLY when a builder hands me blue-prints, there's absolutely NOTHING on the roof outline to give me any idea how to do the take-off. no useable scale, no real dimensions.. there's exact measurements for foundation, framing, etc... but nothing for roof surface area.

so i generally just end up BSing it... i estimate by joist and eave (if eaves length is even included) length, then calculate run to rise... and for a gable-to-gable roof, this works fine.. but get some decorative hips and valleys and short gables and crap involved- it all goes out the window. it's of absolutely zero use to me.

is my problem that i'm getting handed crappy blue-prints, or do i just not even know what i don't know? how easily are you extracting roof take offs from blue-prints?

can anybody recommend a book on the topic? i don't need a degree in architecture- seems like it should be a simple thing...


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## griz (Nov 26, 2009)

No offense, but I think the problem is you.

Even a for chit set of plans notes overhangs, pitches & have a roof framing plan. Scaling some of these dimensions, especially for a roofer, can be challenging...

Get a good scale, familiarize yourself with it.

Get some old plans with a known quantity & scale it out.

No easy tricks....just a little practice to build confidence...

Then there's the guys that take the square footage & use a multiplier...

What ever works best for you...:thumbsup:

Just pay very close attention to the details...


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## Jaws (Dec 20, 2010)

Even if there aren't dimensions it should be to scale, use a scale ruler and figure the dimensions. Sq ft divided into squares, linear ft for ridge.


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## slowsol (Aug 27, 2005)

I do it all the time. I use a take off program, but could easily do it otherwise.

Take off the foundation, add overhangs, multiply for pitch, add waste. Turn in bid, get contract, sub roof out to cheaper roofer, collect check. Done.


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## OldNBroken (Feb 8, 2008)

Elevations and Roof plan. All the info you ever need will be on these pages. Sounds like you just need some practice and edjumacation reading prints. Nothing wrong with that.


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## Mr Latone (Jan 8, 2011)

Renegade said:


> Elevations and Roof plan. All the info you ever need will be on these pages. Sounds like you just need some practice and edjumacation reading prints. Nothing wrong with that.


Exactly.

After that its just areas of triangles and rectangles.

Still have to do a little extra work to get the hip lengths though.


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## CompleteW&D (May 28, 2011)

Even the worst set of plans are drawn to some scale. 3/8" = 1' for example. So all you need is a drafting scale like this:










Each side has a different scale. All you do is pick the correct side and start measuring away. You measure the square footage of the roof's foot print. All you do then once you get your square footage, is multiply the SF by the pitch factor for that particular roof, then add waste to get your field shingles. Next, measure for starter and hip/ridge shingles and you're done with your take off.

Even on the most complex, cut up roof, you can do a full take off in about 10 minutes once you learn how to use one of these $5 drafting squares.

Here is a handy pitch factor chart for you....
http://connected.typepad.com/connected/files/roof_pitch_factors.pdf

Just remember when using this particular pitch factor chart, that you will have about 10% more waste on a hip roof with a lot of valleys than you will on a straight gable roof. I typically figured my wast at about 5% on a straight gabled roof and as much as 15% on a roof that is all cut up. Generally, it falls somewhere in between.

Good luck! :thumbsup:


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