Calculating Waste


Go to the New Roof Waste Calculation Sheet thread. The new link is there.


[quote=“Authentic_Dad, post:57, topic:6663, full:true”]
Why don’t you simply look in the manufacturers installation guide and the best commercial roofer? Insurance isn’t responsible for best practices.[/quote]

I want to know which type of roofing is good for my house??


The kind that doesn’t leak.


I would love to have that Excel sheet with the calculations you percent in your chat.



what about asking insurance for 10% on drip edge?


Could you send a copy of your spreadsheet to



Hi do you mind sending me your excel sheet? We are running in to multiple issues with Allstate in particular giving 6% waste and not separating out ridge and starter.


Go here to get it

Waste Calc Workbook


Holy crap most you guys figure tons of waste!!! I rarely have more that like half square of waste. If the square footage is 2013, I’ll order 21 square. If it is 2063, I’ll order 21.33.


So if you have a 60 square hip with 150 ft of valley and 250 ft of hip you’ll have half a square of waste? And your 20 square roof doesn’t have starter and cap? Most 20 square roofs don’t have much trim scrap because they’re so simple. Who cares about 5% on 20 squares anyway, it amounts to nothing. Try doing some real roofs and then come back and tell me about your 1/2 square crap.


I hope if you sell a 2023sq you don’t only charge for 21sq. It’s about calculating waste not how many shingles you use. If our guys do a 21 sq job and bring back 2 sq that means the estimator did a good job and the crew did a good job…a win win


I would greatly appreciate if you would share the excels sheet with me. Sir i have learned a great deal from your post and replies on this forum. Thanks


I Like Using This FREE Roof Measuring Tool it Helps Me -
You can add waste percentage for the report or order…


@Authentic_Dad I really like your posts, very helpful stuff. I generally put some sort of verbiage in my supplements such as:

"IRC 2009/2012/2015, section R903.1 and R904.1: Roof Assemblies shall be designed and installed in accordance with this code and the approved manufacturers installation instructions. You cannot use 3 tab or dimensional shingles as a starter course.

An underlayment must be applied over the entire deck before the installation of TAMKO shingles. Failure to add underlayment can cause premature failure of the shingles which is not covered by TAMKO’s Limited Warranty.

Products which are acceptable for use as underlayment are:
Asphalt Saturated Felt Underlayments:

• TAMKO No. 15 Asphalt Saturated Organic Felt
• Any TAMKO non-perforated asphalt saturated organic felt
• A non-perforated asphalt saturated organic felt which meets ASTM: D226, Type I or II or ASTM D4869

If you are including starter in the waste, Xactware states the dollar amount and quantity allowed must be a direct representation of the costs if it were separated. This asserts that you must account for the natural roof waste that occurs when you reach a termination or valley and then you can account for any additional items within the waste. For material comparison, 60 LF of ridge cap is equal to 1 bundle of waste."

Something along these lines. Now we dont always use Tamko so the lingo may change just depending. I’ll even go to the lengths of finding the city code enforcer to verify they stand by their adopted IRC. However, sometimes the insurance company will ask for a signed letter from the city code enforcer which they say unless they have, they don’t have to pay per city code.

Anyway, again, your spreadsheet will help greatly and will help alleviate the argument of city code which SF will say “is irrelevant.” It will help me get to the simple argument that they are not paying for enough material.