Dormers are installed to bring natural light, increase usable attic space, and add curb appeal. The cost of a dormer varies with size and its type. For example, a shed dormer and a flat dormer will cost $75-$125 per square foot, while an eyebrow dormer costs $105-$160 per square foot. The total cost of installing a dormer usually ranges from $3,000 to $25,000, depending on the style and the existing roof structure. Another important consideration when adding a dormer is labor cost, which ranges between $35 $55 per hour, per worker. This blog explains these costs in detail.
Dormer Cost Calculator
The following tables show the total average cost and cost per square foot for various dormer types.
| Maximum Cost | $75,000 |
| Average Range | $3,000 - $25,000 |
| Dormer Style | Cost Per Square Foot | Average Total Cost |
| Arched top | $100 to $150 | $25,000 to $37,000 |
| Eyebrow/eyelid* | $105 to $160 | $26,250 to $40,000 |
| Flat roof | $80 to $125 | $20,000 to $31,000 |
| Gable | $110 to $150 | $27,500 to $37,000 |
| Hipped | $115 to $135 | $28,750 to $33,750 |
| Shed | $75 to $120 | $18,750 to $30,000 |
Factors That Affect Dormer Cost
The following are some important factors that affect the dormer costs.
Labor Costs
Homeowners should plan to spend $35 to $55 per hour per worker to install a dormer. The exact price depends on factors such as your location and the contractor’s business model. It's obvious that prices will run higher in urban regions than in rural areas. Additionally, some contractors may charge a fixed project fee rather than an hourly rate.
| Some Tips | It's usually cost-effective to add a dormer when installing a new roof rather than adding one later to an old roof. |
Permits and Inspections
Homeowners will need to hire an engineer to design a dormer that fits their home’s structure. Permits will also be required to ensure the project meets current building codes. The price range for permits is $390 to $1,930. Additionally, you have to pay the municipality in your region for mid- and post-construction inspections.
Roof Deck Replacement
Most of the time, when you add a dormer, it's important to remove the existing roof deck. So, the average cost of removal ranges from $5 to $8 per foot of roof deck. However, the expenditure may vary depending on the project size, shape, and location.
Roofing Material
It's evident that the roofing material used in the dormer affects the project cost. For example, the metal roof is great but expensive and requires specialized installation; however, asphalt shingles are affordable and can be installed easily. Additionally, you will need to consider the cost of removal of the old roofing material. Lastly, the costs add up when you hire an expert to complete the work.
Dormer Size in Square Footage
The cost of a large dormer increases because extra framing, roofing, and materials will be required. A wider dormer needs more structural reinforcement and sheathing, and also more roofing shingles or siding to put everything together.
Structural Reinforcement
Sometimes older houses or truss-framed roofs need necessary modifications to support a dormer. The modifications include reframing the roof structure, reinforcing rafters, or rebuilding load paths. With trusses involved, you will need to hire a licensed structural engineer to design and review the modifications. It will automatically increase the overall project price by adding $1,000 to $3,000.
Location
The labor and material cost depends on your location. For example, if you are residing in areas with a high cost of living, you may have to pay 15% to 30% more than the national average. Additionally, the final cost is affected by local permit costs, availability of skilled trades, and local building codes.
How Much Does It Cost to Add a Dormer Roof Type?
Here are several dormer types, varying in style and price.
Cost of a Shed Dormer Addition
Installation of shed dormers usually costs between $75 - $120 per square foot. The shed dormer has a flat and sloped roof, which can reduce construction costs. Also, this dormer style is used to maximize square footage.
The cost to install a wall roof dormer, a type of shed dormer, ranges from $75 to $115 per square foot. Its front aligns with the exterior wall of the house to get a flawless look, rather than settling between the roof’s slope.
Cost of a Gable Dormer Addition
It's the most popular dormer type, and generally the installation costs around $110 $150 per square foot. This style comes with a triangular shape with peaked roofs and efficiently sheds water and snow. Additionally, flared gables provide more shade because they can easily extend farther out from the house.
| Some Tips | In northeastern states, two gable dormers and a shed dormer are used to make a Nantucket dormer. |
Cost of a Flat Roof Addition
The installation price for a flat roof ranges from $80 to $125 per square foot. This dormer style may leak at any time and isn't considered as attractive as other dormer types. However, flat dormers are easy and affordable to build.
Cost of a Hip Roof Dormer Addition
To install a hip roof dormer type, homeowners can expect to pay around $110 to $140 per square foot. It’s recognised by its pyramid-like appearance, with three sloping sides rather than two.
Cost of Recessed or Inset Dormer Addition
The installation price of a recessed dormer ranges between $70 and $150 per square foot. This dormer requires minimal material to build from and is fixed into the roof. However, it provides less square footage, and the risk of leaking is higher.
Cost of Faux and Prefab Dormer Addition
Homeowners have to pay around $65 to $90 per square foot to install a faux and prefab dormer. The total price could range from $2,800 to $8,900. It has other names, like blind or prefabricated dormer, and is simply attached to the house’s exterior, which eventually decreases construction costs. But it doesn't allow air, space, or natural light.
Cost of Arched Top or Barrel Rood Dormer Addition
The installation cost of an arched-top or barrel roof dormer ranges from $100 to $150 per square foot. If you want a dormer with a rounded top and a smaller size, an arched top is a great choice for this.
Cost of Eyebrow Dormer Addition
If you want to install a small, rounded dormer that aligns easily with the roof, an eyebrow dormer is a good choice. The installation cost is usually between $100 and $160. Additionally, it offers great aesthetics but lets in less natural light than other dormers.
