What Are Dormer Additions? How It Adds More Light (And Value) To Your Attic
A bit of air and sunlight may be just what your attic needs
Highlights
Dormer additions add extra space and/or light to your home.
There are three main types of dormers: gable, shed, and hipped.
Dormers cost anywhere from $2,500–$20,000.
There is no standard way to size dormer additions.
Dormers require professional installation.
Does your home have an unused attic or maybe an upstairs room that is too small or too dark? Adding a dormer could turn these underutilized spaces into integral parts of your home. Dormers add both versatility and value to your existing residence. Use this guide to decide if a dormer addition would be the right project for you.
What Is a Dormer Addition?
A dormer is a structure that projects out from the plane of a sloped roof, often including a window. The dormer structure has its own roof, siding, and sometimes even gutters that tie into the existing elements of your home. Some consider dormers the “eyes” of a house.
The word “dormer” comes from “dormitorium,” which means “a place for sleeping.” Dormers are often added to unfinished attic spaces to convert them into bedrooms.
5 Types of Dormers
The style of your dormer's framing should match the architecture of your home. Some gables feature individual windows and look as if they sprung up out of your current roof. Others significantly alter the shape of your home, extending from end to end with multiple windows on one dormer. Just as you would a house, the type of dormer will vary depending on what both looks best and offers the most practical solution.
Gabled Dormers
Gabled dormers are the most common styles, blending with both modern and historic homes.
Includes one window per dormer
Peak at the top and slope down on either side
Sit perpendicular to the roof's slope
Shed Dormers
Maximize the headroom in your attic by connecting windows into one long dormer.
Roof slopes toward the front of the house
Links several windows together into one dormer
Maximizes the living space on the top floor
Roof of dormer has a flatter pitch
Hipped Dormers
Once you get to know the types of roof styles for your home, you'll recognize the hipped style that slants upward on both the front and the sides of the dormer.
Ideal for hipped-roof homes
Increases headroom on the top floor
Requires more roofing materials
Recessed dormers
While these dormers come in a range of roof styles, they are always set back into the structure of the main roof to extend the walls.
Blends more seamlessly with the home's roof
Commonly called inset dormers
Requires fewer building materials
Eyebrow dormers
A curved dormer roof offers a softer aesthetic, as if it's popping out of the home like eyebrows.
Sit atop single or multiple windows
Ideal for roofs with curved shingles to mimic thatching
Adds light to top floors but minimal space
What Is the Purpose of a Dormer Addition?
The intent of a dormer is to add more natural light through the use of a window and/or to add more usable space to your floor plan. A dormer will either increase the ceiling height in a room or, if large enough, add more square footage.
Dormers can also become an important design feature, enhancing the character and interest of your home’s curb appeal.
Pros and Cons of Dormer Additions
The cost to finish an attic can be tricky to balance, especially when turning such an often-cavernous space into a welcoming living area. Dormer windows offer a budget-friendly approach compared to altering the height of the roof. That being said, there are ups and downs to dormer additions that are important to consider.
Pros
If you have a great contractor on your side and they give you the green light to add a dormer addition, here are some of the things to look forward to.
Increase usable square footage on your top floor
Adds natural light to the space
Increase ventilation in the attic
Boosts curb appeal by breaking up your roof's design
Can add resale value to your home
Cons
On the other hand, remember that major structural changes to your roof can be costly and will often require more upkeep to handle the elements.
Dormer additions cost an average of $12,000 each
May not be an option for older and more fragile roofs
Often requires additional gutters
Depending on the design, it can lead to more leakage
Not a DIYable project
What Size Should Dormer Additions Be?
There is no set standard on sizing dormer additions. Ultimately, it will come down to what looks best on your home and achieves the extra space or lighting you desire.
You will need to consider factors such as spacing between dormers, the slope of your current roof, the proportions of your home, the size of the windows you will use, and the codes for required egress.
To properly size your dormer additions, work with a licensed architect near you who will take all of these design factors into consideration.
How Much Does It Cost to Add a Dormer?
The typical cost to add a dormer ranges from $2,500 to $20,000, with an average cost of around $12,000. Be sure to look into your options for how to finance a home addition to ensure it's the right move for you at this time.
The type of dormer you choose to install has a significant influence on the cost as well as the project size and any required permits. Keep in mind, most dormer additions will provide a return-on-investment of about 40% due to the increase in usable space.
Factors to Consider Before Adding a Dormer to Your House
Before you set out to install dormers on your home, consider these factors that could influence your decision.
Not All Roofing Systems Are Compatible With Dormers
Depending on the type of structural roof framing you have, adding dormers to your house may prove difficult. Request a visit from an experienced general contractor to discuss the feasibility of a dormer addition project.
You may need to install additional structural framing in order to support new dormers, which will significantly add to the overall cost.
Dormer Additions Are Not a DIY Project
Adding a dormer to your home is a huge undertaking. It involves altering structural components and installing watertight seals. If these tasks are done improperly, it can lead to unsafe living conditions and costly repairs down the road.
Dormer additions are a project best left to the professionals. Contact a local roofer near you to discuss the possibility of adding dormers to your home.
Dormers Can Be Prefabricated or Custom Built
If your home has a simple roofline and you want a standard dormer size and style, a prefabricated dormer is a good option to consider.
Prefabricated dormers are already framed, insulated, and roofed. They are first set with a crane and then a contractor will finish the installation with proper flashing and siding.
If you have specific design or sizing preferences, you are better off with custom-built dormers.
Dormers Are Sometimes a Source of Leaks
The sidewalls of dormers can be a source of leaks. This can happen if a general contractor who isn’t a roofer doesn’t properly flash the area. Roofing pros recommend hiring a roofer to handle the sidewalls of the dormer—even if a contractor builds the dormer itself. A roofer will likely use step flashing for the dormer’s sloped walls, as well as an ice and water shield up the wall behind the siding.
Frequently Asked Questions
A dormer can increase the value of your home by up to 20% when designed and installed correctly. As you consider adding a dormer to your home, ensure that the addition blends with your home's style and enhances your curb appeal, instead of acting as a distraction. Additionally, always hire a professional to design and install the window to avoid water damage.
Yes, in most cases, you can add dormers to an existing roof. However, you should always work with a local general contractor when considering this structural change. These pros will bring in structural engineers and expert roofers to ensure it's the best match for your roof's style and stability.
Building a dormer can take anywhere from one week to six months to build. Single, gabled dormers will take minimal design and installation time. Larger dormers or those with complex designs—such as shed or eyebrow dormers—will require more time to safely alter your roof and customize the insert.