Dormer window costs

There are several good reasons why building a dormer can add value to your home. For example, you can immediately add a new bedroom or create a beautiful study wherefrom you can also have a wide view. Would you also like to have a dormer built, but are curious about the costs? We can help you!

Prices for a dormer

The prices for dormer windows can vary greatly depending on the specialist. The average price is between $2650-$4250. You may be wondering what you will get in return. There are different options that influence the prices for dormers. Think about accessories like shutters and mosquito nets, the dormer’s width, height, and angle of inclination.

How much does a dormer window cost?

The cost of a standard dormer window with a height of 5 feet and a width of 8 feet, which are the most common dimensions in the US, is on average:

Material Average construction costs
Wooden dormer windows From $3400
Plastic dormer From $4000
Polyester dormer From $5000


Please note that the above prices are based on the standard dimensions of 5 feet in height and 8 feet in width. If you want to install a dormer window with a width of more than 8 feet, you must take into consideration the prices below:

Prices for a flat roof:

Width Average cost
10 feet $3200-$3850
13 feet $4250-$5100
16 feet $5300-$6450
20 feet $6450-$7750


Prices for a tiled roof:

Width Average cost
10 feet $4200-$5000
13 feet $5550-$6700
16 feet $7000-$8400
20 feet $8400-$10100


Decisions that affect the price of a dormer

With the above information you probably already know a lot, but there is more. Some other decisions also have an influence on the dormer’s price. We would also like to list these options for you:

Option 1: Difference between ready-made and custom-made

The first choice you must make is the one related to the design of the dormer. Do you prefer a prefabricated dormer, or a customized design? A prefabricated dormer will always be cheaper, but it has the disadvantage that it can hardly be customized. In any case, we would be happy to give you an overview of the price difference between the two constructions.

Material Prefabricated Customized
Wooden dormer windows From $3450 From $4450
Plastic dormer From $3950 From $5000
Polyester dormer From $5050 Not applicable


Option 2: The material used

Previously on this page it became clear that there can be a significant difference, due to the materials used.

Option 3: Flat roof or tiled roof?

The type of roof construction can also have a significant effect on the price. Do you have a flat roof or a tiled roof?

Flat roof: In case of a flat roof you are lucky. Most prices that are calculated for a dormer already include a flat roof. In this situation, only a small adaptation to the existing roof construction is required, and this can usually be done without a permit.

Tiled roof: Things will be completely different if you have a tiled or pitched roof. In this situation, you no longer need to consider maintenance work (except in the case of a wooden dormer), as the dirt and rainwater run off the roof by itself. In addition, roof tiles (which are used in most cases on a tiled roof) have an excellent life span of about 80 years. Please note that if you install a dormer on a tiled roof, you will have to expect an average surcharge of about 900€ compared to the installation of a dormer on a flat roof.

Compare dormer prices

It is always wise to compare prices. Especially when it comes to large investments. Not only do you want the cheapest price, but also the best quality. You will not want your dormer to need replacing within a few years. Therefore, compare up to 6 quotes from dormer window specialists in your region and save hundreds of Dollars.