# Waste Factor



## MEL (Apr 7, 2007)

How much do you add in for waste on most roof jobs?


----------



## BrandConst (May 9, 2011)

I use 15% across the board on everything.


----------



## Grumpy (Oct 8, 2003)

depends on the size of the job and the complexity of the job. 15% seems enormous IMO. I can't recall ver having an actual 15% waste factor on any job and would hate to finish a job with 3-4 squares left in the driveway, or worse yet, a commercial job with 30 squares left over!


I trust my tape measure and my reading ability. I will go no less than 5% on anything. This would be for a large job that's not too cut up or a very simple two side gable job with no valleys or hips. Typically on a single family residence I am somewhere like 7%. If it's real cut up something like 10%. I can't recall ever adding more than 10%. According to my sales manual, my estimators are instructed to add no less than 7%. 

I do my math a little more complex than the average salesman. I break the roof down into shapes and then do the basic geometry/algebra formulas, I don't take the square footage of the foot print and multiply x a pitch factor. if I did that, maybe I'd add 15% too. 

I also make a complete material list for every job that I order. I don't lump anything together. If I need half a box of screws or nails, I charge the customer for a full box. If I have to buy a full box they pay for a full box. If I need 5' of trim coil, I still charge the customer for the full roll of trim coil. I charge the customer for what ever materials I may need to order for their job... if I so happen to have some in storage, good for me. 

On single ply jobs, I add zero waste, and figure out exactly how many rolls and what sizes of rolls I will need. The waste is what ever is left. For example, let's say you have a 50 square building, someone may think of it as 50 squares plus 10% waste. i think of it as 6' rolls on the perimiter and 10' rolls in the field for a total of 3 6' rolls x 100' each and 4 10' rolls x 100' each. The waste is what ever is left, in this case it happens to be 8 squares. 

Let's say I figure a roof and figure I need 90' of hip and ridge, well a bundle of hip and ridge is 30' which leaves zero for waste so I will add a whole bundle, a whole 30'. In this case the waste factor is about 34%. However let's say I have 110' of hip and ridge and a bundle is 30', I order the same 4 bundles but in this case only have a waste factor of about 9%. 




One last thing to remember is I mark 2% waste into my over head and profit and call it "erros and ommissions", not my measurements. This way I am still covered for mis-measures but don't have alot of actual material left over.


----------



## MEL (Apr 7, 2007)

I have my own method for shingle roofs. On a gable roof I add 2’ to the width for waste on the rake edge or a wall. For example if the roof measures 24 ft wide I count it as 26 ft wide and that will take care of my waste. I always have a few bundles left over.

However I think I am going to have to start using exact measurements so that I can document everything for insurance adjusters if I go after that market.

I’m using Contracker EZ software and it has a feature built in that will add a waste factor of 10% for a gable roof, 17% for a hip roof, or 0% if I select “flat” as the type of roof. Typically I have not used the built in waste factors. 

The software will factor in the pitch for me if I measure from the ground.

Also the data base will allow me to enter a waste factor for each individual item; I can set it to any % I want.

I think 10% is on the high side and 17% is way too high.


----------



## Grumpy (Oct 8, 2003)

Insurance adjusters usually measure to the half foot then add 10% waste across the board.


----------



## dougger222 (Jan 29, 2004)

I charge 10/15/20 waste factor but rarely go that high. For example consider a typical 50sq gable roof with 5sq of waste. If the roof isn't that cut up you may have a couple squares of waste. Same size roof now a hip roof at 7.5sq waste. Unless it's cut to ribbons more than likely you'll have a lot of left over bundles at 15% waste factor.

Lots of experiance will determin what waste you need for what type of roof your doing.


----------



## Roofsafe (Apr 16, 2008)

You can cut the waste factor on your valleys to half if you pre-cut the valleys, saves taking shingles off the roof by the bundles.


----------



## jmiller (May 14, 2010)

I just try to make sure we have too many shingles and have to return some. I hate when it's 48 and I said 45, compared to having 50. I usually count with out a tape measure and add .1.


----------



## RandyB1986 (Jan 2, 2009)

Roofsafe said:


> You can cut the waste factor on your valleys to half if you pre-cut the valleys, saves taking shingles off the roof by the bundles.


How do you "pre-cut" a valley?


----------



## DFW Roofing (Mar 4, 2011)

The common 15% figure is not just for waste, but also starter and ridge.

A very cut up house with many hips and valleys can easily go over that figure.


----------



## MJW (Jan 27, 2006)

DFW Roofing said:


> The common 15% figure is not just for waste, but also starter and ridge.
> 
> A very cut up house with many hips and valleys can easily go over that figure.


Still using 3 tabs or what?


----------



## DFW Roofing (Mar 4, 2011)

MJW said:


> Still using 3 tabs or what?


attempting humor???

Works for most all products. Certainly more accurate means, but how much time do you invest in each bid? 

Best Method

Roof+
Starter+
Ridge+
Waste

Waste can be accurately calculated:

waste / salvage

Rake: .3 / 1.0
Hip: .7 / .5
Closed Valley 2.2 / 1.0


----------



## MJW (Jan 27, 2006)

DFW Roofing said:


> attempting humor???
> 
> Works for most all products. Certainly more accurate means, but how much time do you invest in each bid?
> 
> ...


Nope, but completely lost by what you just posted.


----------



## JWRoofing (May 5, 2011)

I go to the nearest foot, round up to the nearest third of a square. Then I measure the ridge to get an exact number for the Timber Tex or Seal-a-ridge. We keep extra thirty in the box truck in case we are short. 

JW
____________________
Miami Commercial Roofing
http://http://www.jacksinspects.com/miami-mold-remediation.htmllMiami Mold Remediation


----------



## MikeGC (Dec 6, 2008)

1. Depends on the roof simplicity or complexity

2. I have consistently found its a more profitable investment of my time to measure more accurately rather than faster.

3. Every roof measurement gets more accurate as the typical amount of waste for hips, valleys, rake and ridge is learned for each size and type of roof lines

4. Being short sucks payroll dollars 

5. Small material returns on occasion can be nice lunch money for a day or two


----------



## Mr Latone (Jan 8, 2011)

When measuring a roof, waste can be factored in at a lot of levels.

For the following, I an referring to typical laminate architectural shingles:

Are you sloppy with a tape measure and always round up to the next foot even if it's only 2" over. After the generous measurements, do you then add additional percentage for waste?


I stress the above because it's possible to exaggerate unnecessarily.

A simple gable roof with no valleys (up and over) can be installed with damn near 0% waste. Starters are cut and the other half is used for the top course. Steps are cut and completely used. Filling in the rake at the end of the courses, pieces are used until there is nothing but a sliver left.

When roofing into a valley one can figure half a shingle waste for each course that goes into the valley (for single cut closed style) A hip will take less than a third of a shingle per course.

It may sound like I am fussing over the above waste estimate, but if one gets used to it and works it into their take-off, it's quite straight forward and extremely accurate.

With the price of 30yr approaching $100/sq it will pay to get it right.

When a sub wastes a square, they get paid as if they installed it. The contractor now pays for the wasted material and the labor.

Pay the sub the proper rate for the complexity of the job and work together on minimizing waste through effective use of materials.

When working with employees use the same approach for material management.


Waste factors do not have to be unknown. There are fairly definitive quantities of materials needed to cover different roof layouts.


If one nails their material estimate the job will be priced the way it needs to be priced. Fair to you. Fair to the customer. It's a helluva a lot better business practice to have a known profit, than to somehow squeeze it from a "waste factor".


As an aside:

If you KNOW the material the job will take, you may add something to the order for possible damage (bundles do sometimes get delivered with fork damage) but these aren't something you eat and ultimately don't add cost. They are returnable.


----------



## MEL (Apr 7, 2007)

DFW Roofing said:


> attempting humor???
> 
> Waste can be accurately calculated:
> 
> ...


What do those numbers represent?


----------



## MEL (Apr 7, 2007)

I agree, with the cost of material going up accuracy is more important now than ever before.

My software totals the amount of bundles that I need for precut starters on all edges and how many bundles of hip & ridge shingles I need.

I’ve been using a 10% waste factor for the following components:
Starters
Hip and ridge
Underlayment
Drip edge

I haven’t been using a waste factor for shingles because I add it into my measurements. For example if a gable roof is 30 ft long on the eave edge I’ll count that as 32 ft. The extra 2 ft is my waste factor. It works but I’m thinking about going to a % method for greater accuracy.

I could probably get by with a waste factor of 5% for the shingles.

I have my estimating system set to round up to the nearest square. If it comes out to 30.33 squares it round up to 31 square. This is on top of any % I have figured in for waste. I do that way because I don’t want the installers to run out of material.


----------



## DFW Roofing (Mar 4, 2011)

MEL said:


> What do those numbers represent?


Those are waste factors from the CertainTeed "Master Shingle Applicator" manual - ask a CT rep to send you one.

Not going to repeat their entire manual, but they give your different waste factors for rake, hips, and valleys...very accurate if you wish to take the time.

For bids I am comfortable with quick and dirty, then recalculate on the jobs I get for more accurate orders.


----------



## Grumpy (Oct 8, 2003)

DFW Roofing said:


> The common 15% figure is not just for waste, but also starter and ridge.
> 
> A very cut up house with many hips and valleys can easily go over that figure.


Using a waste factor for starters and ridge is a bad idea. Sure on an average job you can somewhat accurately predict a waste factor. With a cut up job, that waste factor for hip and starter is off. With a large roof it's off. Any roof not average, the waste factor for hip and ridge will be off. Better just to hmmmm measure the hip ridge and starter.


----------

