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How to Bid a Roofing Job

Stop Underbidding and Win More Business 

You could be leaving money on the table every time you hand a client an estimate. According to Roofing Contractor magazine, 90 percent of roofers regularly underbid jobs. This is mainly due to paying more attention to materials than the complexity of the labor involved in a particular project. 

In this post, we’ll show you how to bid a roofing job with an estimate that will both appeal to potential clients and ensure that you’re leaving room for profit. Here’s what to do.

Estimate Your Roofing Job’s Material Costs

Figuring out your material costs is the first step in the bid process. Work carefully and keep detailed notes to make sure you’re giving yourself an accurate estimate. Sloppy work during this process sets the stage for underbidding. Here’s how to do things right:

Step 1: Determine Condition of the Roof

Evaluate the condition of the existing flashing.

  • If it can’t be reused, make a note to factor replacement flashing into your material costs.
  • Find how many layers of shingles are currently in place.
  • Check local building codes to see if you can shingle over the existing layer(s).
  • If building codes allow another layer, make sure the current shingles are in good enough condition.
  • If another layer can’t be added, make a note to factor the cost of removal (both labor and materials) into your estimate.

Step 2: Get Precise Measurements

  • Determine the roof’s number of squares by taking the exterior square footage of the house and dividing by 100.
  • Calculate the slope of the roof using the “rise over run”  formula.
  • Multiply your squares by your slope’s corresponding multiplier. Note this final number as the total squares you’ll be installing.
Roof Slope
Less than 5:12
Between 6:12 and 9:12
1.24 on the lower end
1.4 on the higher end
Larger than 9:12
1.4 on the lower end
1.7 on the higher end


Step 3: Determine All Needed Materials

In addition to the squares of shingles the job will take, make a list of all the other materials you’ll need, and their approximate amounts. This usually includes:

Step 4: Calculate Material Costs

  • Get in touch with your suppliers to estimate the overall costs of each item on your list.
  • For shingles and underlayment, clients often like to see the cost per square or square foot broken out, so go ahead and make note of those numbers now.
  • Finally, add in the sales tax.

With your material costs in hand, you’re almost ready to start writing out your formal bid. But there’s still a little legwork left.

Don’t Forget to Add in Labor and Overhead

This is where most roofers end up lowballing themselves. Remember that your roofing bid shouldn’t just account for the labor needed to install the new shingles. You should also be accounting for the added time and complexity of challenges like:

  • Working on a steep slope. 
  • Making repairs to the roof deck.
  • Working particularly high off the ground.
  • Shingling a roof with a complex shape.
  • Removing existing shingles – especially multiple layers.
  • Working around an unusually large number of skylights, vents or chimneys.

Once you’ve got a handle on your labor costs, don’t forget to account for overhead like:

  • Your workers’ comp rate.
  • Any permits you need to pull.
  • Fuel costs and vehicle maintenance.
  • A percentage of the rent and utilities on your office space.

Finally, add in either a percentage markup or a total dollar amount for the profit margin you’re looking to make.   

Roofer at Work

Now It’s Time to Write Up Your Roofing Estimate

Writing a good roofing estimate is all about making it easy for potential clients to understand what they’re paying for while communicating the added value your business offers. These are the basics you should include:

  • A breakdown of material costs, either by the square or by the square foot.
  • Labor costs.
  • Cleanup costs.
  • Permit costs and information.
  • Proof of your licensure, workers’ comp and liability insurance.
  • Start and end dates for the job.
  • Basic payment terms (you’ll give the full details in your contract once a client has accepted your bid.)

Many roofers give only the total price, so simply listing each cost as a separate item will help separate your bid from the competition. But you should also create a positive impression of your service by:

  • Including testimonials from past clients.
  • Providing warranties on your workmanship.
  • Listing the materials you’ll use and including information showing their quality.
  • Explaining how you’ll fix any problems you noticed during your inspection.

Cement your bid’s good impression by using a professional looking template—you can find plenty of free options online—that includes your business’s name, contact information and logo. This will make you look much more trustworthy than a company who gives out handwritten estimates.

Start Bidding Better

Using these tips, you’ll be able to write roofing estimates that give potential clients a better impression of your work while ensuring that you’re not leaving money on the table by underbidding. Check out our Trades & Construction section for more resources on growing your roofing business. Got any tricks for making cost estimates quicker and easier?  Pass them on below. Then get out there and start bidding roofing jobs more successfully than ever.

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