Dumpsters.com logo

How to Bid on Roofing Jobs Successfully

Write a competitive roofing bid with our seven-step process.

By Jon Behm| Last Updated:02/14/2024
A multi-story home with various roof sections.

How to Estimate Roofing Material and Labor Costs

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.

We’ll show you how to bid a roofing job that accounts for everything from labor to a roofing dumpster. Here’s what to do.

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.

2. Get Precise Measurements

Accuracy is key to determining a precise bid. Start by finding the roof’s number of squares by taking the exterior square footage of the house and dividing by 100. Then, calculate the slope of the roof using the “rise over run” formula. Finally, 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

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 nails, flashing, underlayment, moisture barriers and roofing dumpsters.

4. Calculate Material Costs

Calculating the material costs is where many bids can get off track. You'll want to get as holistic of a picture as you can, so start by getting in touch with your suppliers to estimate the overall costs of each item on your list. Don't forget to add in the sales tax.

Lightbulb icon


It's easy to forget the underlayment when calculating your costs. Luckily, it's easy to figure out how much you'll need. A roll of underlayment will cover four squares. So, simply divide your total number of squares by four.

5. Factor in Disposal Expenses

You'll want to include the disposal costs as part of your bid. While it won't be as significant of a cost as materials like shingles and underlayment, forgetting to factor in a dumpster will be large enough that your bid will stand out from the rest for the wrong reasons.

Renting a dumpster with a company like Dumpsters.com is ideal for bids. You can use tools like our shingle weight calculator or shingle disposal guide to help determine how much you're tossing, and the best way to get rid of it. However, the best way we'll help you win a quote is by providing an upfront price. You'll get an all-inclusive price that won't cause you to go back to the project manager after the shingles are at the landfill to ask for more money. That's because we include the disposal fee from the start instead of tacking it on afterwards.

6. Consider Labor Costs

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.

7. Account for Overhead

Now comes the theoretical costs you need to include. These can include things 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.

Tips for Writing a Roofing Estimate to Win New Business

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 that gives out handwritten estimates.

How Dumpsters.com Helps Roofing Contractors Stay on Budget

Our goal is to simplify waste removal to help you win your bids. We do this with a streamlined billing process and customized invoices to help you get the numbers you need upfront. Once you've won the job, our self-service Enterprise Portal gives you a live look at all your active and inactive jobs throughout the country. This lets you protect your bottom line while keeping your operations running smoothly.

What Do You Think?

Have thoughts on roofing bids? We're listening. Head over to Twitter, LinkedIn, Pinterest or Facebook and use #dumpstersblog to join the conversation.

Get a Dumpsters.com Contractor Account Today