2025 Tar and Gravel Roof Cost

Cost by Roof Size

The size of your building is the most significant tar and gravel roof cost factor. The price per square foot for this type of flat roof averages $6 but can range from $4 to $10. For a standard 1,700-square-foot flat roof, expect to pay $10,200. You can use the building sizes in the table below to get an idea of where your total will fall.

Roofer Cost

The process of installing a tar and gravel roof is labor-intensive, so between 60% and 70% of the total will go toward the cost of hiring a roofer. Labor costs total between $6,000 and $7,000. The materials for your tar and gravel roof will account for between $3,000 and $4,100.

Structural Engineer Cost

A tar and gravel roof includes multiple layers of heavy asphalt and roofing felt to make up the main waterproof membrane, as well as a layer of heavy gravel on top of the finished roof to add protection from punctures and UV damage. As a result, tar and gravel roofs weigh significantly more than a single-ply type of flat roof, like TPO or EPDM.

If your building can’t support the heavier loads, you may need to hire a structural engineer to reinforce your building’s structural components. This would add between $2,000 and $5,000 to your total, pushing your price from the average of $10,200 closer to $12,000 or more.

Cost by Location

Home improvement projects that are largely labor-focused, like tar and gravel roof installation, vary widely based on the local cost of living, as labor costs will scale accordingly. As a result, you’ll pay significantly more for a tar and gravel roof in major cities and states with an above-average cost of living.

Additional Cost Factors

While roof size and location are the most impactful cost factors to consider, some other factors can also affect your total installation cost.

Drainage System

All flat roofs need a drainage system to route pooling water off the roof to reduce the risk of structural damage and roof leaks. If you already have a drainage system installed on your old flat roof, you won’t have to budget any additional money. If you’ve run into pooling problems in the past, you should budget between $800 and $1,500 per additional drain you need installed to prevent ongoing issues.

Optional Add-Ons

All tar and gravel roof installations will include the basics, like a waterproof membrane, flashing, and the aggregate over the installed roof. However, there are a few add-on options you can choose to add layers of protection to your new flat roof. Each of these will add to your flat roof replacement cost but can avoid property damage and reduce how often you need repairs.

• Vapor barrier: A vapor barrier sits beneath your flat roof insulation and protects the building materials below from moisture. Adding a vapor barrier to your tar and gravel roof costs between $1,000 and $4,000, depending on the size of your roof.

• Insulation: All flat roofs are insulated, but you have some options when it comes to the type of insulation you choose. Spray foam insulation and extruded polystyrene insulation won’t cost anything additional, but upgrading to rigid foam board or polyiso insulation can increase your total by up to $1,000.

• Cover board: If you choose spray foam insulation for your flat roof, you’ll need a cover board over it to provide a smooth, flat layer to lay down your waterproof membrane. This will add between $300 and $1,200 to your total, depending on the size of your building and the quality of materials.

Unexpected Repairs

When your roofer removes your old roofing material, there’s a chance they’ll uncover damaged building materials below, especially if you’re replacing your roof due to signs of a roof leak appearing in your home. Replacing rafters and roof decking that have rotted or insulation that has become waterlogged can add anywhere between $500 and $2,000 to your roof replacement costs.

Permits

Most municipalities require permits before you can replace your roof, and permits cost between $150 and $400, depending on your location and roof size. The roofer you hire will pull the permits and normally include the charge in your total, but you’ll be responsible for paying the permit fees.

Removal of Old Roof

It’s uncommon for roofers to charge separately to remove your old roof, so this service will almost always be included in your initial estimate. However, your professional may charge higher fees depending on the type of roof you had previously. Single-ply roofing materials like TPO, EPDM, and PVC are easier and faster to remove than a built-up roof or modified bitumen asphalt roof. As such, your price can vary a bit depending on the type. The average cost for roof removal and disposal is between $1,000 and $1,500.

Tar and Gravel Roof Repair vs. Replacement

Repairing a tar and gravel roof costs an average of $1,200 and can total anywhere between $150 and $8,000, depending on the type of issue and the extent of the damage. Installing a new tar and gravel roof costs $10,200, so a replacement will always be more expensive.

However, replacing over repairing your roof is a better option if there are signs you need a roof replacement or if the repair costs total more than 50% of the cost of a new roof, or $5,000, on average, in the case of a tar and gravel roof. A full replacement is best if you’ve been experiencing ongoing leaks or property damage or if you know your old roof is reaching the end of its useful lifespan. You can speak with a local flat roofing company to help you decide if a replacement is a better option for you.

How to Save Money on a Tar and Gravel Roof

Tar and gravel roofs can cost as much as $25,000, making them an expensive home improvement project. There are a few things you can do to save some money in the process, though.

• Skip the vapor barrier, if possible. If you live in an area that doesn’t see a lot of humidity or rainfall, it might be possible to forgo adding a vapor barrier under your tar and gravel roof. This can save you between $1,000 and $4,000.

• Choose your insulation type carefully. There are a few types of insulation you can choose when installing a tar and gravel roof. Spray insulation can be an affordable option upfront, but choosing rigid foam insulation with a higher R-value could end up saving you money in the long run by maximizing building efficiency.

• Consider removing the old roof yourself. If you’re comfortable with it, you can remove your old roofing material yourself and haul it away to save between $1,000 and $1,500. Just be sure to coordinate with your roofer and get the work done before they arrive to install the new roof.

• Think about a roof overlay. Roof overlays involve placing a new layer of roofing directly over the old roof without removing it. It’s possible to do this with a tar and gravel roof in some situations, and it costs significantly less.

Does a Tar and Gravel Roof Increase Home Value?

Installing any kind of new roof will increase your home value, as buyers will walk into the deal knowing that they won’t have to worry about roof leaks, repairs, or replacements shortly after closing. Replacing a flat roof will have less of a positive impact on home value, though, as it’s not visible from the street and won’t improve curb appeal. Still, you can expect a return on investment (ROI) of between 30% and 40% when you install a new tar and gravel roof.

How Angi Gets Its Cost Data

Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We extensively research project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We rely on reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects. 

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