Dormers bring light and space to your home’s interior while increasing curb appeal. Adding one to your home is a major undertaking, and installation costs are wide-ranging. Prices depend on the it’s type and size, but you can expect a dormer to cost around $24,000.* 

We have outlined the various costs required to add dormers to your home’s roof so you can make an informed decision before contacting a local builder with your plans.

*All cost data sourced from Angi.com and HomeAdvisor.com.

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What Is a Dormer?

A dormer is a roof structure—usually containing a window–that adds architectural interest to your second-floor or attic space. These are typically triangular and situated on the roof’s slope, protruding from its plane. A dormer provides additional living space as well as increased natural light and ventilation. 

Not all dormers are alike. Types of dormers include gabled dormers, shed dormers, hipped dormers, and more. Gabled dormers are triangular and project vertically from the roof. Shed dormers are rectangular and project horizontally. Hipped dormers project at an angle that allows rain to run off easily. 

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How Much Does Each Style of Dormer Cost?

Dormers come in at least a dozen different styles. The most common dormer types are gable dormers and hip dormers. Gable dormers have the same angle as the roof, while hip dormers are angled at 45 degrees. There may be additional installation costs to consider, depending on your roof’s style.

Arched Top Dormer Cost

Eyebrow/Eyelid Dormer Cost

Eyelid or eyebrow dormers are especially popular in traditional, high-end coastal architecture and usually cost $26,250–$40,000. 

Flat Roof Dormer Cost

A flat roof dormer doesn’t require any structural changes to your house and costs $20,000–$31,250.

Gable Dormer Cost

These dormers can be simple to build, so they may cost less than other types. Depending on size, framing details, and other architectural factors, your budget for a gable dormer should be around $32,500.

Hipped Dormer Cost

Shed Dormer Cost

Because these types of dormers are larger than most, they also cost more, typically around $18,750–$30,000.

Dormer Style	Cost per Square Foot	Average Total Cost
Arched top	$100–$150	$25,000–$37,500
Eyebrow/eyelid*	$105–$160	$26,250–$40,000
Flat roof	$80–$125	$20,000–$31,250
Gable	$110–$150	$27,500–$37,500
Hipped	$115–$135	$28,750–$33,750
Shed	$75–$120	$18,750–$30,000

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Benefits of Adding a Dormer

A dormer is a great way to increase your home’s living space. It can also add another roof overhang for protection from rain, sun, and snow. A dormer looks especially appealing on Cape Cod, châteauesque, American foursquare, and neocolonial homes.

Dormer windows offer extra light, additional space, and plenty of ventilation. They also add aesthetic value that prospective buyers may love, increasing your home’s valuation.

Drawbacks to Adding a Dormer

On the other hand, dormers are expensive and challenging to install. If made cheaply, they can rot, warp, or gap around the flashing. To ensure that your roof lasts a long time, experts recommend annual inspections and roof maintenance checks that also involve dormers. These visits should include replacing any damaged flashing and checking seals around windows, doors, chimneys, and vents to prevent leaks.

Pros

• Added curb appeal
• Increase your home’s living space
• Offer extra light, additional space, and ventilation

Cons

• Expensive and challenging to install
• Requires maintenance
• If made cheaply, they can rot and warp

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What Are Other Factors That Impact Dormer Costs?

Many factors can impact dormer costs, from the type of dormer to the material used to construct it. Learn more about the major expenses in the dropdown sections below. 

Labor Costs

Expect to spend about $35–$55 per hour, per employee to install a dormer. The actual cost of labor depends on several variables, such as your location and the contractor’s business model. Typically, fees run higher in urban areas than rural ones, and some contractors may charge a flat fee instead of an hourly rate. It’s typically more cost-effective to install a dormer when putting on a new roof than to add one to an existing roof. 

Permits and Inspections

Your project will require the work of an engineer who can create a dormer design that fits with your home’s structure. Permits will then be needed to ensure that the project meets current building codes. These range in price from $390–$1,930. Your municipality may also require mid- and post-construction inspections, which you’ll pay for.

Roof Deck Replacement

When adding a dormer, you’ll almost always need to remove the existing roof deck. The average cost of removal is around $5–$8 per foot of roof deck, but expenses will vary depending on project size, shape, and location.

Roofing Material

The roofing material used on the dormer will impact the project cost. For example, a metal roof is more expensive and requires special installation, while asphalt shingles are easier to install and less expensive. You’ll also have to factor in the old roofing material and how expensive it is to take off. The material cost may also be impacted by whether an expert does the work.

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Can You Install a Dormer Yourself?

We don’t recommend installing roofing yourself for several reasons—the most prevalent being that it’s dangerous. Professional roofers are experts and have experience in advanced home improvement projects. 

DIY Dormer Installation

Adding a dormer to your home is not a DIY project. You’ll need to hire a contractor for the job. The roof should undergo an inspection before construction begins. During the project, you’ll need temporary support structures while the dormer is being built. Then, the dormer will have to be framed, roofed, shingled, and inspected—all major tasks requiring specialized skill and knowledge.

Professional Dormer Installation

Installing a dormer requires intricate knowledge of carpentry as well as building codes and regulations that may vary regionally. A professional will understand these and other project intricacies and can solve any problems that may arise along the way. Here’s how the process usually works:

1. You set up an initial consultation for the contractor to provide a quote. 
2. The contractor surveys your house to figure out square footage and what’s needed in terms of materials.
3. The contractor provides a detailed proposal and payment schedule or financing information.
4. You sign a contract with the roofing company you want, and they get started on your project. 

We recommend getting quotes from at least three contractors before making a final decision.

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Is It Worth Adding a Dormer?

A dormer can add light, space, ventilation, and even value to your home. But adding a dormer to your roof is not an inexpensive, do-it-yourself project. It requires a professional’s skills and tools.

The cost of adding dormers depends on factors like your roof size, roof truss cost, and number of dormers. It also varies based on the materials used and your location. Expect to spend up to $30,000 on materials and labor; call a local builder or contractor to get a more detailed quote.

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FAQs About the Cost To Add a Dormer

How much space does a dormer add?

A new dormer can add up to 250 square feet of space to your house. This will depend on the dormer style and your home’s construction.

How long does it take to add a dormer?

Building a dormer may take four weeks to six months to complete. It’s a long and complex task, but the end result is often worth it.

Do dormers add value to a house?

A new dormer offers an excellent return on investment and can increase your home value. You’ll also get to enjoy the extra light and living space a dormer provides while living in the home.

Do I need an architect to add a dormer?

You may not need an architect to add a new dormer, but you’ll likely need a building permit. A building permit for a dormer usually costs $390–$1,930, with a national average of $1,160.

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